Category Archives: food

Could engineered nanoparticles be behind rise in obesity and metabolic disorders?

The researchers haven’t published a study and they have used fruit flies as their testing mechanism (animal models) so, it’s a little difficult (futile) to analyze the work at this stage but it is intriguing. A June 9, 2015 news item on Azonano announces a research collaboration  designed to examine the impact engineered nanoparticles have on the gut and the gut microbiome,

Researchers at Binghamton University believe understanding nano particles’ ability to influence our metabolic processing may be integral to mediating metabolic disorders and obesity, both of which are on the rise and have been linked to processed foods.

Anthony Fiumera, associate professor of biological sciences, and Gretchen Mahler, assistant professor of biomedical engineering, are collaborating on a research project funded by a Binghamton University Transdisciplinary Areas of Excellence (TAE) grant to discover the role ingested nanoparticles play in the physiology and function of the gut and gut microbiome.

A June 8, 2015 Binghamton University news release, which originated the news item, describes the reasoning behind the research,

The gut microbiome is the population of microbes living within the human intestine, consisting of tens of trillions of microorganisms (including at least 1,000 different species of known bacteria). Nanoparticles, which are often added to processed foods to enhance texture and color, have been linked to changes in gut function. As processed foods become more common elements of our diet, there has been a significant increase in concentrations of these particles found in the human body.

Fiumera works in vivo with fruit flies while Mahler works in vitro using a 3-D cell-culture model of the gastrointestinal (GI) tract to understand how ingesting nanoparticles influences glucose processing and the gut microbiome. By using complementary research methods, the researchers have helped advance each other’s understanding of nanoparticles.

Using fruit flies, Fiumera looks at the effects of nanoparticles on development, physiology and biochemical composition, as well as the microbial community in the GI tract of the fly. The fly model offers two advantages: 1) research can be done on a wide range of traits that might be altered by changes in metabolism and 2) the metabolic processes within the fly are similar to those in humans. Fiumera also aims to investigate which genes are associated with responses to the nanoparticles, which ultimately may help us understand why individuals react differently to nanoparticles.

For this project, Mahler expanded her GI tract model to include a commensal intestinal bacterial species and used the model to determine a more detailed mechanism of the role of nanoparticle exposure on gut bacteria and intestinal function. Early results have shown that nanoparticle ingestion alters glucose absorption, and that the presence of beneficial gut bacteria eliminates these effects.

Mahler was already investigating nanoparticles when she reached out to Fiumera and proposed they combine their respective expertise. With the help of undergraduate students Gabriella Shull and John Fountain and graduate student Jonathan Richter, Fiumera and Mahler have begun to uncover some effects of ingesting nanoparticles. Since they are using realistic, low concentrations of nanoparticles, the effects are slight, but eventually may be additive.

The most interesting aspect of this research (to me) is the notion that the impact may be additive. In short, you might be able to tolerate a few more nanoparticles in your gut but as more engineered nanoparticles become part of our food and drink (including water) and your gut receives more and more that tolerance may no longer possible.

There is increasing concern about engineered nanoparticles as they cycle through environment and the US Environmental Protection Agency (EPA) funded a programed by Arizona State University (ASU), LCnano Network (part of the EPA’s larger Life Cycle of Nanomaterials project). You can find out more about the ASU program in my April 8, 2014 post (scroll down about 50% of the way).

Getting back to Binghamton, I look forward to hearing more about the research as it progresses.

Silver nanoparticles and wormwood tackle plant-killing fungus

I’m back in Florida (US), so to speak. Last mentioned here in an April 7, 2015 post about citrus canker and zinkicide, a story about a disease which endangers citrus production in the US, this latest story concerns a possible solution to the problem of a fungus, which attacks ornamental horticultural plants in Florida. From a May 5, 2015 news item on Azonano,

Deep in the soil, underneath more than 400 plant and tree species, lurks a lethal fungus threatening Florida’s $15 billion a year ornamental horticulture industry.

But University of Florida plant pathologist G. Shad Ali has found an economical and eco-friendly way to combat the plant destroyer known as phytophthora before it attacks the leaves and roots of everything from tomato plants to oak trees.

Ali and a team of researchers with UF’s Institute of Food and Agricultural Sciences, along with the University of Central Florida and the New Jersey Institute of Technology, have found that silver nanoparticles produced with an extract of wormwood, an herb with strong antioxidant properties, can stop several strains of the deadly fungus.

A May 4, 2015 University of Florida news release, which originated the news item, describes the work in more detail,

“The silver nanoparticles are extremely effective in eliminating the fungus in all stages of its life cycle,” Ali said. “In addition, it has no adverse effects on plant growth.” [emphasis mine]

The silver nanoparticles measure 5 to 100 nanometers in diameter – about one one-thousandth the width of a human hair. Once the nanoparticles are sprayed onto a plant, they shield it from fungus. Since the nanoparticles display multiple ways of inhibiting fungus growth, the chances of pathogens developing resistance to them are minimized, Ali said. Because of that, they may be used for controlling fungicide-resistant plant pathogens more effectively.

That’s good news for the horticulture industry. Worldwide crop losses due to phytophthora fungus diseases are estimated to be in the multibillion dollar range, with $6.7 billion in losses in potato crops due to late blight – the cause of the Irish Potato Famine in the mid-1800s when more than 1 million people died – and $1 billion to $2 billion in soybean loss.

Silver nanoparticles are being investigated for applications in various industries, including medicine, diagnostics, cosmetics and food processing.  They already are used in wound dressings, food packaging and in consumer products such as textiles and footwear for fighting odor-causing microorganisms.

Other members of the UF research team were Mohammad Ali, a visiting doctoral student from the Quaid-i-Azam University, Islamabad, Pakistan; David Norman and Mary Brennan with the University of Florida’s Plant Pathology-Mid Florida Research and Education Center; Bosung Kim with the University of Central Florida’s chemistry department; Kevin Belfield with the College of Science and Liberal Arts at the New Jersey Institute of Technology and the University of Central Florida’s chemistry department.

Ali’s comment about silver nanoparticles not having any adverse effects on plant growth is in contrast to findings by Mark Wiesner and other researchers at  Duke University (North Carolina, US). From my Feb. 28, 2013 posting (which also features a Finnish-Estonia study showing no adverse effects from silver nanoparticles  in crustaceans),

… there’s a study from Duke University suggests that silver nanoparticles in wastewater which is later put to agricultural use may cause problems. From the Feb. 27, 2013 news release on EurekAlert,

In experiments mimicking a natural environment, Duke University researchers have demonstrated that the silver nanoparticles used in many consumer products can have an adverse effect on plants and microorganisms.

The main route by which these particles enter the environment is as a by-product of water and sewage treatment plants. [emphasis] The nanoparticles are too small to be filtered out, so they and other materials end up in the resulting “sludge,” which is then spread on the land surface as a fertilizer.

The researchers found that one of the plants studied, a common annual grass known as Microstegium vimeneum, had 32 percent less biomass in the mesocosms treated with the nanoparticles. Microbes were also affected by the nanoparticles, Colman [Benjamin Colman, a post-doctoral fellow in Duke’s biology department and a member of the Center for the Environmental Implications of Nanotechnology (CEINT)] said. One enzyme associated with helping microbes deal with external stresses was 52 percent less active, while another enzyme that helps regulate processes within the cell was 27 percent less active. The overall biomass of the microbes was also 35 percent lower, he said.

“Our field studies show adverse responses of plants and microorganisms following a single low dose of silver nanoparticles applied by a sewage biosolid,” Colman said. “An estimated 60 percent of the average 5.6 million tons of biosolids produced each year is applied to the land for various reasons, and this practice represents an important and understudied route of exposure of natural ecosystems to engineered nanoparticles.”

“Our results show that silver nanoparticles in the biosolids, added at concentrations that would be expected, caused ecosystem-level impacts,” Colman said. “Specifically, the nanoparticles led to an increase in nitrous oxide fluxes, changes in microbial community composition, biomass, and extracellular enzyme activity, as well as species-specific effects on the above-ground vegetation.”

Getting back to Florida, you can find Ali’s abstract here,

Inhibition of Phytophthora parasitica and P. capsici by silver nanoparticles synthesized using aqueous extract of Artemisia absinthium by Mohammad Ali, Bosung Kim, Kevin Belfield, David J. Norman, Mary Brennan, & Gul Shad Ali. Phytopathology  http://dx.doi.org/10.1094/PHYTO-01-15-0006-R Published online April 14, 2015

This paper is behind a paywall.

For anyone who recognized that wormwood is a constituent of Absinthe, a liquor that is banned in many parts of the world due to possible side effects associated with the wormwood, here’s more about it from the Wormwood overview page on WebMD (Note: Links have been removed),

Wormwood is an herb. The above-ground plant parts and oil are used for medicine.

Wormwood is used in some alcoholic beverages. Vermouth, for example, is a wine beverage flavored with extracts of wormwood. Absinthe is another well-known alcoholic beverage made with wormwood. It is an emerald-green alcoholic drink that is prepared from wormwood oil, often along with other dried herbs such as anise and fennel. Absinthe was popularized by famous artists and writers such as Toulouse-Lautrec, Degas, Manet, van Gogh, Picasso, Hemingway, and Oscar Wilde. It is now banned in many countries, including the U.S. But it is still allowed in European Union countries as long as the thujone content is less than 35 mg/kg. Thujone is a potentially poisonous chemical found in wormwood. Distilling wormwood in alcohol increases the thujone concentration.

Returning to the matter at hand, as I’ve noted previously elsewhere, research into the toxic effects associated with nanomaterials (e.g. silver nanoparticles) is a complex process.

Metal nanoparticles and gut microbiomes

What happens when you eat or drink nanoparticles, metallic or otherwise? No one really knows. Part of the problem with doing research now is there are no benchmarks for the quantity we’ve been ingesting over the centuries. Nanoparticles do occur naturally, as well, people who’ve eaten with utensils made of or coated with silver or gold have ingested silver or gold nanoparticles that were shed by those very utensils. In short, we’ve been ingesting any number of nanoparticles through our food, drink, and utensils in addition to the engineered nanoparticles that are found in consumer products. So, part of what researchers need to determine is the point at which we need to be concerned about nanoparticles. That’s trickier than it might seem since we ingest our nanoparticles and recycle them into the environment (air, water, soil) to reingest (inhale, drink, eat, etc.) them at a later date. The endeavour to understand what impact engineered nanoparticles in particular will have on us as more are used in our products is akin to assembling a puzzle.

There’s a May 5, 2015 news item on Azonano which describes research into the effects that metallic nanoparticles have on the micriobiome (bacteria) in our guts,

Exposure of a model human colon to metal oxide nanoparticles, at levels that could be present in foods, consumer goods, or treated drinking water, led to multiple, measurable differences in the normal microbial community that inhabits the human gut. The changes observed in microbial metabolism and the gut microenvironment with exposure to nanoparticles could have implications for overall human health, as discussed in an article published in Environmental Engineering Science, a peer-reviewed journal from Mary Ann Liebert, Inc., publishers. The article is available free on the Environmental Engineering Science website until June 1, 2015.

A May 4, 2015 Mary Ann Liebert publisher news release on EurekAlert, which originated the news item, describes the research in more detail (Note: A link has been removed),

Alicia Taylor, Ian Marcus, Risa Guysi, and Sharon Walker, University of California, Riverside, individually introduced three different nanoparticles–zinc oxide, cerium dioxide, and titanium dioxide–commonly used in products such as toothpastes, cosmetics, sunscreens, coatings, and paints, into a model of the human colon. The model colon mimics the normal gut environment and contains the microorganisms typically present in the human microbiome.

In the article “Metal Oxide Nanoparticles Induce Minimal Phenotypic Changes in a Model Colon Gut Microbiota” the researchers described changes in both specific characteristics of the microbial community and of the gut microenvironment after exposure to the nanoparticles.

Here’s a link to and a citation for the paper,

Metal Oxide Nanoparticles Induce Minimal Phenotypic Changes in a Model Colon Gut Microbiota by Alicia A. Taylor, Ian M. Marcus Ian, Risa L., Guysi, and Sharon L. Walker. Environmental Engineering Science. DOI:10.1089/ees.2014.0518 Online Ahead of Print: April 24, 2015

I’ve taken a quick look at the research while it’s still open access (till June 1, 2015) to highlight the bits I consider interesting. There’s this about the nanoparticle (NP) quantities used in the study (Note: Links have been removed),

Environmentally relevant NP concentrations were chosen to emulate human exposures to NPs through ingestion of both food and drinking water at 0.01 μg/L ZnO NP, 0.01 μg/L CeO2 NP, and 3 mg/L TiO2 NP (Gottschalk et al., 2009; Kiser et al., 2009, 2013; Weir et al., 2012; Keller and Lazareva, 2013). Recent work has also indicated that adults in the USA ingest 5 mg TiO2 per day, half of which is in the nano-size range (Lomer et al., 2000; Powell et al., 2010). Exposure routes and reliable dosing information of NPs that are embedded in solid matrices are difficult to predict, and this is often a limitation of analytical techniques (Nowack et al., 2012; Yang and Westerhoff, 2014). The exposure levels used in this study were predominately selected from literature values that give predictions on amount of NPs in water and food sources (Gottschalk et al., 2009; Kiser et al., 2009; Weir et al., 2012; Keller and Lazareva, 2013; Keller et al., 2013).

For anyone unfamiliar with chemical notations, ZnO NP is zinc oxide nanoparticle, 0.01 μg/L is one/one hundredth of a microgram per litre,  CeO2 is cesisum dioxide NP, and TiO2 is titanium dioxide NP while 3 mg/L, is 3 milligrams per litre.

After assuring the quantities used in the study are the same as they expect humans to be ingesting on a regular basis, the researchers describe some of the factors which may affect the interaction between the tested nanoparticles and the bacteria (Note: Links have been removed),

It is essential to note that interactions between NPs and bacteria in the intestines may be dependent on numerous factors: the surface charge of the NPs and bacteria, the chemical composition and surface charge of the digested food, and variability in diet. These factors may ultimately correlate to effects seen in humans on an individual basis. In fact, similar work has demonstrated that exposing common NPs found in food to stomach-like conditions will change their surface chemistry from negative to neutral or positive, causing the NPs to interact with negatively charged mucus proteins in the gastrointestinal tract and, in turn, affecting the transport of NPs within the intestine (McCracken et al., 2013). The purpose of this work was to measure responses of the microbial community during the NP exposures. Based on previous research, it is anticipated that the NPs altered by stomach-like conditions would also cause changes in the gut environment (McCracken et al., 2013).

Here’s some of what they discovered,

Our initial hypothesis, that NPs induce phenotypic changes in a gut microbial community, was affirmed through significant measurable effects seen in the data. Tests that supported that NPs caused changes in the phenotype included hydrophobicity, EPM, sugar content of the EPS, cell size, conductivity, and SFCA (specifically butyric acid) production. Data for cell concentration and the protein content of the EPS demonstrated no significant results. Data were inconclusive for pH. With such a complex biological system, it is very likely that the phenotypic and biochemical changes observed are combinations of responses happening in parallel. The effects seen may be attributed to both changes induced by the NPs and natural phenomena associated with microbial community activity and other metabolic processes in a multifaceted environment such as the gut. Some examples of natural processes that could also influence the phenotypic and biochemical parameters are osmolarity, active metabolites, and electrolyte concentrations (Miller and Wood, 1996; Record et al., 1998).

Here’s the concluding sentence from the abstract,

Overall, the NPs caused nonlethal, significant changes to the microbial community’s phenotype, which may be related to overall health effects. [emphasis mine]

This research like the work I featured in a June 27, 2013 posting points to some issues with researching the impact that nanoparticles may have on our bodies. There was no cause for immediate alarm in 2013 and it appears that is still the case in 2015. However, that assumes quantities being ingested don’t increase significantly.

US Dept. of Agriculture awards $3.8M for nanotechnology research grants

I wonder just how much funding the US Dept. of Agriculture (USDA) is devoting to nanotechnology this year (2015). I first came across an announcement of $23M in the body of a news item about Zinkicide (my April 7, 2015 posting),

Found in Florida orchards in 2005, a citrus canker, citrus greening, poses a serious threat to the US state’s fruit industry. An April 2, 2105 news item on phys.org describes a possible solution to the problem,

Since it was discovered in South Florida in 2005, the plague of citrus greening has spread to nearly every grove in the state, stoking fears among growers that the $10.7 billion-a-year industry may someday disappear.

Now the U.S. Department of Agriculture has awarded the University of Florida a $4.6 million grant aimed at testing a potential new weapon in the fight against citrus greening: Zinkicide, a bactericide invented by a nanoparticle researcher at the University of Central Florida.

An April 29, 2015 article by Diego Flammini for Farm.com describes the latest USDA nanotechnology funding announcement,

In an effort to increase America’s food security, nutrition, food safety and environmental protection, the United States Department of Agriculture’s (USDA) National Institute of Food and Agriculture (NIFA) announced $3.8 million in nanotechnology research grants.

Flammini lists three of the eight recipients,

University of Georgia
With $496,192, the research team will develop different sensors that are able to detect fungal pathogens in crops. The project will also develop a smartphone app for farmers to have so they can access their information whenever necessary.

Rutgers University
The school will use its $450,000 to conduct a nationwide survey about nanotechnology and gauge consumer beliefs about it and its relationship to health. Among the specifics it will touch on is the use of visuals to communicate nanotechnology.

University of Massachusetts
The researchers will concentrate their $444,200 on developing a platform to detect pathogens in food that is better than the current methods.

A full list of the recipients can be found in the April 27, 2015 USDA news release featuring the $3.8M in awards,

  • The University of Georgia, Athens, Ga., $496,192
  • University of Iowa, Iowa City, Iowa., $496,180
  • University of Kentucky Research Foundation, Lexington, Ky., $450,000
  • University of Massachusetts, Amherst, Mass., $444,200
  • North Dakota State University, Fargo, N.D., $149,714
  • Rutgers University, New Brunswick. N.J., $450,000
  • Pennsylvania State University, University Park, University Park, Pa., $447,788
  • West Virginia University, Morgantown, W. Va., $496,168
  • University of Wisconsin-Madison, Madison, Wis., $450,100

You can find more details about the awards in this leaflet featuring the USDA project descriptions for the eight recipients.

Essential oil nanoemulsions for foodborne bacteria

An April 30, 2015 news item on Azonano describes essential oil research at Wayne State University (Detroit, Michigan, US),

Nearly half of foodborne illnesses in the U.S. from 1998 through 2008 have been attributed to contaminated fresh produce. Prevention and control of bacterial contamination on fresh produce is critical to ensure food safety. The current strategy remains industrial washing of the product in water containing chlorine. However, due to sanitizer ineffectiveness there is an urgent need to identify alternative antimicrobials, particularly those of natural origin, for the produce industry.

A team of researchers at Wayne State University have been exploring natural, safe and alternative antimicrobials to reduce bacterial contamination. Plant essential oils such as those from thyme, oregano and clove are known to have a strong antimicrobial effect, but currently their use in food protection is limited due to their low solubility in water. The team, led by Yifan Zhang, Ph.D., assistant professor of nutrition and food science in the College of Liberal Arts and Sciences, explored ways to formulate oil nanoemulsions to increase the solubility and stability of essential oils, and consequently, enhance their antimicrobial activity.

An April 29, 2015 Wayne State University news release (also on EurekAlert), which originated the news item, expands on the theme,

“Much of the research on the antimicrobial efficacy of essential oils has been conducted using products made by mixing immiscible oils in water or phosphate buffered saline,” said Zhang. “However, because of the hydrophobic nature of essential oils, organic compounds from produce may interfere with reducing the sanitizing effect or duration of the effectiveness of these essential oils. Our team set out to find a new approach to inhibit these bacteria with the use of oregano oil, one of the most effective plant essential oils with antimicrobial effect.”

Zhang, and then-Ph.D. student, Kanika Bhargava, currently assistant professor of human environmental sciences at the University of Central Oklahoma, approached Sandro da Rocha, Ph.D., associate professor of chemical engineering and materials science in the College of Engineering at Wayne State, to explore options.

“In our research, we discovered that oregano oil was able to inhibit common foodborne bacteria, such as E. coli O157, Salmonella and Listeria, in artificially contaminated fresh lettuce” said Zhang. “We wanted to explore the possibility of a nanodelivery system for the oil, which is an area of expertise of Dr. da Rocha.”

The team initially considered the use of solid polymeric nanoparticles for the delivery of the oil, but da Rocha suggested the use of nanoemulsions.

“My team felt the use of nanoemulsions would improve the rate of release compared to other nanoformulations, and the ability of the food grade surfactant to wet the surface of the produce,” said da Rocha. “We were able to reduce L. monocytogenes, S. Typhimurium, and E. coli O157 on fresh lettuce. Former Ph.D. student Denise S. Conti, now at the Generics Division of the FDA, helped design the nanocarriers and characterize them.”

The team added that while there is still work to be done, their study suggests promise for the use of essential oil nanoemulsions as a natural alternative to chemicals for safety controls in produce.

“Our future research aims to investigate the antimicrobial effects of essential oil nanoemulsions in various combinations, as well as formulate the best proportions of each ingredient at the lowest possible necessary levels needed for food application, which ultimately will aid in maintaining the taste of the produce.”

Here’s a link to and a citation for the paper,

Application of an oregano oil nanoemulsion to the control of foodborne bacteria on fresh lettuce by Kanika Bhargava, Denise S. Conti, Sandro R.P. da Rocha, and Yifan Zhang. Food Microbiology Volume 47, May 2015, Pages 69–73, DOI: 10.1016/j.fm.2014.11.007

This paper is behind a paywall.

Carbon nanotubes sense spoiled food

CNT_FoodSpolage

Courtesy: MIT (Massachusetts Institute of Technology)

I love this .gif; it says a lot without a word. However for details, you need words and here’s what an April 15, 2015 news item on Nanowerk has to say about the research illustrated by the .gif,

MIT [Massachusetts Institute of Technology] chemists have devised an inexpensive, portable sensor that can detect gases emitted by rotting meat, allowing consumers to determine whether the meat in their grocery store or refrigerator is safe to eat.

The sensor, which consists of chemically modified carbon nanotubes, could be deployed in “smart packaging” that would offer much more accurate safety information than the expiration date on the package, says Timothy Swager, the John D. MacArthur Professor of Chemistry at MIT.

An April 14, 2015 MIT news release (also on EurekAlert), which originated the news item, offers more from Dr. Swager,

It could also cut down on food waste, he adds. “People are constantly throwing things out that probably aren’t bad,” says Swager, who is the senior author of a paper describing the new sensor this week in the journal Angewandte Chemie.

This latest study is builds on previous work at Swager’s lab (Note: Links have been removed),

The sensor is similar to other carbon nanotube devices that Swager’s lab has developed in recent years, including one that detects the ripeness of fruit. All of these devices work on the same principle: Carbon nanotubes can be chemically modified so that their ability to carry an electric current changes in the presence of a particular gas.

In this case, the researchers modified the carbon nanotubes with metal-containing compounds called metalloporphyrins, which contain a central metal atom bound to several nitrogen-containing rings. Hemoglobin, which carries oxygen in the blood, is a metalloporphyrin with iron as the central atom.

For this sensor, the researchers used a metalloporphyrin with cobalt at its center. Metalloporphyrins are very good at binding to nitrogen-containing compounds called amines. Of particular interest to the researchers were the so-called biogenic amines, such as putrescine and cadaverine, which are produced by decaying meat.

When the cobalt-containing porphyrin binds to any of these amines, it increases the electrical resistance of the carbon nanotube, which can be easily measured.

“We use these porphyrins to fabricate a very simple device where we apply a potential across the device and then monitor the current. When the device encounters amines, which are markers of decaying meat, the current of the device will become lower,” Liu says.

In this study, the researchers tested the sensor on four types of meat: pork, chicken, cod, and salmon. They found that when refrigerated, all four types stayed fresh over four days. Left unrefrigerated, the samples all decayed, but at varying rates.

There are other sensors that can detect the signs of decaying meat, but they are usually large and expensive instruments that require expertise to operate. “The advantage we have is these are the cheapest, smallest, easiest-to-manufacture sensors,” Swager says.

“There are several potential advantages in having an inexpensive sensor for measuring, in real time, the freshness of meat and fish products, including preventing foodborne illness, increasing overall customer satisfaction, and reducing food waste at grocery stores and in consumers’ homes,” says Roberto Forloni, a senior science fellow at Sealed Air, a major supplier of food packaging, who was not part of the research team.

The new device also requires very little power and could be incorporated into a wireless platform Swager’s lab recently developed that allows a regular smartphone to read output from carbon nanotube sensors such as this one.

The funding sources are interesting, as I am appreciating with increasing frequency these days (from the news release),

The researchers have filed for a patent on the technology and hope to license it for commercial development. The research was funded by the National Science Foundation and the Army Research Office through MIT’s Institute for Soldier Nanotechnologies.

Here’s a link to and a citation for the paper,

Single-Walled Carbon Nanotube/Metalloporphyrin Composites for the Chemiresistive Detection of Amines and Meat Spoilage by Sophie F. Liu, Alexander R. Petty, Dr. Graham T. Sazama, and Timothy M. Swager. Angewandte Chemie International Edition DOI: 10.1002/anie.201501434 Article first published online: 13 APR 2015

© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This article is behind a paywall.

There are other posts here about the quest to create food sensors including this Sept. 26, 2013 piece which features a critique (by another blogger) about trying to create food sensors that may be more expensive than the item they are protecting, a problem Swager claims to have overcome in an April 17, 2015 article by Ben Schiller for Fast Company (Note: Links have been removed),

Swager has set up a company to commercialize the technology and he expects to do the first demonstrations to interested clients this summer. The first applications are likely to be for food workers working with meat and fish, but there’s no reason why consumers shouldn’t get their own devices in due time.

There are efforts to create visual clues for food status. But Swager says his method is better because it doesn’t rely on perception: it produces hard data that can be logged and tracked. And it also has potential to be very cheap.

“The resistance method is a game-changer because it’s two to three orders of magnitude cheaper than other technology. It’s hard to imagine doing this cheaper,” he says.

A city of science in Japan: Kawasaki (Kanagawa)

Happily, I’m getting more nanotechnology (for the most part) information from Japan. Given Japan’s prominence in this field of endeavour I’ve long felt FrogHeart has not adequately represented Japanese contributions. Now that I’m receiving English language translations, I hope to better address the situation.

This morning (March 26, 2015), there were two news releases from Kawasaki INnovation Gateway at SKYFRONT (KING SKYFRONT), Coastal Area International Strategy Office, Kawasaki City, Japan in my mailbox. Before getting on to the news releases, here’s a little about  the city of Kawasaki and about its innovation gateway. From the Kawasaki, Kanagawa entry in Wikipedia (Note: Links have been removed),

Kawasaki (川崎市 Kawasaki-shi?) is a city in Kanagawa Prefecture, Japan, located between Tokyo and Yokohama. It is the 9th most populated city in Japan and one of the main cities forming the Greater Tokyo Area and Keihin Industrial Area.

Kawasaki occupies a belt of land stretching about 30 kilometres (19 mi) along the south bank of the Tama River, which divides it from Tokyo. The eastern end of the belt, centered on JR Kawasaki Station, is flat and largely consists of industrial zones and densely built working-class housing, the Western end mountainous and more suburban. The coastline of Tokyo Bay is occupied by vast heavy industrial complexes built on reclaimed land.

There is a 2014 video about Kawasaki’s innovation gateway, which despite its 14 mins. 39 secs. running time I am embedding here. (Caution: They highlight their animal testing facility at some length.)

Now on to the two news releases. The first concerns research on gold nanoparticles that was published in 2014. From a March 26, 2015 Kawasaki INnovation Gateway news release,

Gold nanoparticles size up to cancer treatment

Incorporating gold nanoparticles helps optimise treatment carrier size and stability to improve delivery of cancer treatment to cells.

Treatments that attack cancer cells through the targeted silencing of cancer genes could be developed using small interfering RNA molecules (siRNA). However delivering the siRNA into the cells intact is a challenge as it is readily degraded by enzymes in the blood and small enough to be eliminated from the blood stream by kidney filtration.  Now Kazunori Kataoka at the University of Tokyo and colleagues at Tokyo Institute of Technology have designed a protective treatment delivery vehicle with optimum stability and size for delivering siRNA to cells.

The researchers formed a polymer complex with a single siRNA molecule. The siRNA-loaded complex was then bonded to a 20 nm gold nanoparticle, which thanks to advances in synthesis techniques can be produced with a reliably low size distribution. The resulting nanoarchitecture had the optimum overall size – small enough to infiltrate cells while large enough to accumulate.

In an assay containing heparin – a biological anti-coagulant with a high negative charge density – the complex was found to release the siRNA due to electrostatic interactions. However when the gold nanoparticle was incorporated the complex remained stable. Instead, release of the siRNA from the complex with the gold nanoparticle could be triggered once inside the cell by the presence of glutathione, which is present in high concentrations in intracellular fluid. The glutathione bonded with the gold nanoparticles and the complex, detaching them from each other and leaving the siRNA prone to release.

The researchers further tested their carrier in a subcutaneous tumour model. The authors concluded that the complex bonded to the gold nanoparticle “enabled the efficient tumor accumulation of siRNA and significant in vivo gene silencing effect in the tumor, demonstrating the potential for siRNA-based cancer therapies.”

The news release provides links to the March 2015 newsletter which highlights this research and to the specific article and video,

March 2015 Issue of Kawasaki SkyFront iNewsletter: http://inewsletter-king-skyfront.jp/en/

Contents

Feature video on Professor Kataoka’s research : http://inewsletter-king-skyfront.jp/en/video_feature/vol_3/feature01/

Research highlights: http://inewsletter-king-skyfront.jp/en/research_highlights/vol_3/research01/

Here’s a link to and a citation for the paper,

Precise Engineering of siRNA Delivery Vehicles to Tumors Using Polyion Complexes and Gold Nanoparticles by Hyun Jin Kim, Hiroyasu Takemoto, Yu Yi, Meng Zheng, Yoshinori Maeda, Hiroyuki Chaya, Kotaro Hayashi, Peng Mi, Frederico Pittella, R. James Christie, Kazuko Toh, Yu Matsumoto, Nobuhiro Nishiyama, Kanjiro Miyata, and Kazunori Kataoka. ACS Nano, 2014, 8 (9), pp 8979–8991 DOI: 10.1021/nn502125h Publication Date (Web): August 18, 2014
Copyright © 2014 American Chemical Society

This article is behind a paywall.

The second March 26, 2015 Kawasaki INnovation Gateway news release concerns a DNA chip and food-borne pathogens,

Rapid and efficient DNA chip technology for testing 14 major types of food borne pathogens

Conventional methods for testing food-borne pathogens is based on the cultivation of pathogens, a process that is complicated and time consuming. So there is demand for alternative methods to test for food-borne pathogens that are simpler, quick and applicable to a wide range of potential applications.

Now Toshiba Ltd and Kawasaki City Institute for Public Health have collaborated in the development of a rapid and efficient automatic abbreviated DNA detection technology that can test for 14 major types of food borne pathogens. The so called ‘DNA chip card’ employs electrochemical DNA chips and overcomes the complicated procedures associated with genetic testing of conventional methods. The ‘DNA chip card’ is expected to find applications in hygiene management in food manufacture, pharmaceuticals, and cosmetics.

Details

The so-called automatic abbreviated DNA detection technology ‘DNA chip card’ was developed by Toshiba Ltd and in a collaboration with Kawasaki City Institute for Public Health, used to simultaneously detect 14 different types of food-borne pathogens in less than 90 minutes. The detection sensitivity depends on the target pathogen and has a range of 1E+01~05 cfu/mL.

Notably, such tests would usually take 4-5 days using conventional methods based on pathogen cultivation. Furthermore, in contrast to conventional DNA protocols that require high levels of skill and expertise, the ‘DNA chip card’ only requires the operator to inject nucleic acid, thereby making the procedure easier to use and without specialized operating skills.

Examples of pathogens associated with food poisoning that were tested with the “DNA chip card”

Enterohemorrhagic Escherichia coli

Salmonella

Campylobacter

Vibrio parahaemolyticus

Shigella

Staphylococcus aureus

Enterotoxigenic Escherichia coli

Enteroaggregative Escherichia coli

Enteropathogenic Escherichia coli

Clostridium perfringens

Bacillus cereus

Yersinia

Listeria

Vibrio cholerae

I think 14 is the highest number of tests I’ve seen for one of these chips. This chip is quite an achievement.

One final bit from the news release about the DNA chip provides a brief description of the gateway and something they call King SkyFront,

About KING SKYFRONT

The Kawasaki INnovation Gateway (KING) SKYFRONT is the flagship science and technology innovation hub of Kawasaki City. KING SKYFRONT is a 40 hectare area located in the Tonomachi area of the Keihin Industrial Region that spans Tokyo and Kanagawa Prefecture and Tokyo International Airport (also often referred to as Haneda Airport).

KING SKYFRONT was launched in 2013 as a base for scholars, industrialists and government administrators to work together to devise real life solutions to global issues in the life sciences and environment.

I find this emphasis on the city interesting. It seems that cities are becoming increasingly important and active where science research and development are concerned. Europe seems to have adopted a biannual event wherein a city is declared a European City of Science in conjunction with the EuroScience Open Forum (ESOF) conferences. The first such city was Dublin in 2012 (I believe the Irish came up with the concept themselves) and was later adopted by Copenhagen for 2014. The latest city to embrace the banner will be Manchester in 2016.

Disinfectants without chemicals for the food industry

Michael Berger in his March 16, 2015 Nanowerk Spotlight article profiles some very interesting research into replacing chemicals with water nanostructures,

The burden of foodborne diseases worldwide is huge, with serious economic and public health consequences. The CDC [US Centers for Disease Control] estimates that each year in the USA approximately 48 million people get sick, 128,000 get hospitalized and 3,000 die from the consumption of food contaminated with pathogenic microorganisms. The food industry is in search of effective intervention methods that can be applied from ‘farm to fork’ to ensure the safety of the food chain and be consumer and environment friendly at the same time.

In the food industry, chemicals are routinely used to clean and disinfect product contact surfaces as well as the outer surface of the food itself. These chemicals provide a necessary and required step to ensure that the foods produced and consumed are as free as possible from microorganisms that can cause foodborne illness.

Food activists are concerned that some of the chemicals used by the food industry for disinfection can cause health issues for consumers. A prime example is the current discussion in Europe about ‘American chlorine chicken’. …

Berger goes on to highlight the research being conducted at the Harvard T. Chan School of Public Health (Harvard University). The team announced a new technique called Engineered Water Nanostructures (EWNS), which is generated by electrospraying water. The team published this paper in 2014,

A chemical free, nanotechnology-based method for airborne bacterial inactivation using engineered water nanostructures by Georgios Pyrgiotakis, James McDevitt, Andre Bordini, Edgar Diaz, Ramon Molina, Christa Watson, Glen Deloid, Steve Lenard, Natalie Fix, Yosuke Mizuyama, Toshiyuki Yamauchi, Joseph Brain and Philip Demokritou. Environ. Sci.: Nano, 2014,1, 15-26 DOI: 10.1039/C3EN00007A

First published online 28 Nov 2013

This paper is open access.

More recently, the team has proved the efficacy of this technique on stainless steel surfaces and tomatoes. A Feb. 25, 2015 Harvard T. Chan School of Public Health news release provides information about the costs of foodborne diseases and goes on to describe the technique and the latest experiments,

The burden of foodborne diseases worldwide is huge, with serious economic and public health consequences. The U.S. Department of Agriculture’s (USDA’s) Economic Research Service reported in 2014 that foodborne illnesses are costing the economy more than $15.6 billion and about 53,245 Americans visit the hospital annually due to foodborne illnesses. The food industry is in search of effective intervention methods that can be applied form “farm to fork” to ensure the safety of the food chain and be consumer and environment friendly at the same time.

Researchers at the Center for Nanotechnology and Nanotoxicology of the Harvard T. Chan School of Public Health are currently exploring the effectiveness of a nanotechnology based, chemical free, intervention method for the inactivation of foodborne and spoilage microorganisms on fresh produce and on food production surfaces. This method utilizes Engineered Water Nanostructures (EWNS) generated by electrospraying of water. EWNS possess unique properties; they are 25 nm in diameter, remain airborne in indoor conditions for hours, contain Reactive Oxygen Species (ROS), have very strong surface charge (on average 10e/structure) and have the ability to interact and inactivate pathogens by destroying their membrane.

In a study funded by the USDA and just published this week in the premier Environmental Science and Technology journal, the efficacy of these tiny water nanodroplets, in inactivating representative foodborne pathogens such as Escherichia coli, Salmonella enterica and Listeria innocua, on stainless steel surfaces and on tomatoes, was assessed showing significant log reductions in inactivation of select food pathogens. These promising results could open up the gateway for further exploration into the dynamics of this method in the battle against foodborne disease. More importantly this novel, chemical-free, cost effective and environmentally friendly intervention method holds great potential for development and application in the food industry, as a ‘green’ alternative to existing inactivation methods.

Here’s a link to and a citation for the latest paper,

Inactivation of Foodborne Microorganisms Using Engineered Water Nanostructures (EWNS) by Georgios Pyrgiotakis, Archana Vasanthakumar, Ya Gao, Mary Eleftheriadou, Eduardo Toledo, Alice DeAraujo, James McDevitt, Taewon Han, Gediminas Mainelis, Ralph Mitchell, and Philip Demokritou. Environ. Sci. Technol., Article ASAP DOI: 10.1021/es505868a Publication Date (Web): February 19, 2015

Copyright © 2015 American Chemical Society

This paper is behind a paywall. The researchers have made this image illustrating a ‘water shell’s’ effect on a bacterium located on a tomato,

Courtesy: Researchers and the American Chemical Society

Courtesy: Researchers and the American Chemical Society

I’m not sure how chemical companies are going to feel but this is very exciting news. Still, one has to wonder just how much water this technique would require for full scale adoption and would it be reusable?

Dunkin’ Donuts and nano titanium dioxide

It’s been a busy few days for titanium dioxide, nano and otherwise, as the news about its removal from powdered sugar in Dunkin’ Donuts products ripples through the nano blogosphere. A March 6, 2015 news item on Azonano kicks off the discussion with an announcement,

Dunkin’ Brands, the parent company of the Dunkin’ Donuts chain, has agreed to remove titanium dioxide, a whitening agent that is commonly a source of nanomaterials, from all powdered sugar used to make the company’s donuts. As a result of this progress, the advocacy group As You Sow has withdrawn a shareholder proposal asking Dunkin’ to assess and reduce the risks of using nanomaterials in its food products.

Here’s a brief recent history of Dunkin’ Donuts and nano titanium dioxide from my Aug. 21, 2014 posting titled, FOE, nano, and food: part two of three (the problem with research),

Returning to the ‘debate’, a July 11, 2014 article by Sarah Shemkus for a sponsored section in the UK’s Guardian newspaper highlights an initiative taken by an environmental organization, As You Sow, concerning titanium dioxide in Dunkin’ Donuts’ products (Note: A link has been removed),

The activists at environmental nonprofit As You Sow want you to take another look at your breakfast doughnut. The organization recently filed a shareholder resolution asking Dunkin’ Brands, the parent company of Dunkin’ Donuts, to identify products that may contain nanomaterials and to prepare a report assessing the risks of using these substances in foods.

Their resolution received a fair amount of support: at the company’s annual general meeting in May, 18.7% of shareholders, representing $547m in investment, voted for it. Danielle Fugere, As You Sow’s president, claims that it was the first such resolution to ever receive a vote. Though it did not pass, she says that she is encouraged by the support it received.

“That’s a substantial number of votes in favor, especially for a first-time resolution,” she says.

The measure was driven by recent testing sponsored by As You Sow, which found nanoparticles of titanium dioxide in the powdered sugar that coats some of the donut chain’s products. [emphasis mine] An additive widely used to boost whiteness in products from toothpaste to plastic, microscopic titanium dioxide has not been conclusively proven unsafe for human consumption. Then again, As You Sow contends, there also isn’t proof that it is harmless.

“Until a company can demonstrate the use of nanomaterials is safe, we’re asking companies either to not use them or to provide labels,” says Fugere. “It would make more sense to understand these materials before putting them in our food.”

As I understand it, Dunkin’ Donuts will be removing all titanium dioxide, nano-sized or other, from powdered sugar used in its products. It seems As You Sow’s promise to withdraw its July 2104 shareholder resolution is the main reason for Dunkin’ Donuts’ decision. While I was and am critical of Dunkin’ Donuts’ handling of the situation with As You Sow, I am somewhat distressed that the company seems to have acquiesced on the basis of research which is, at best, inconclusive.

Dr. Andrew Maynard, director of the University of Michigan Risk Science Centre, has written a substantive analysis of the current situation regarding nano titanium dioxide in a March 12, 2015 post on his 2020 Science blog (Note: Links have been removed),

Titanium dioxide (which isn’t the same thing as the metal titanium) is an inert, insoluble material that’s used as a whitener in everything from paper and paint to plastics. It’s the active ingredient in many mineral-based sunscreens. And as a pigment, is also used to make food products look more appealing.

Part of the appeal to food producers is that titanium dioxide is a pretty dull chemical. It doesn’t dissolve in water. It isn’t particularly reactive. It isn’t easily absorbed into the body from food. And it doesn’t seem to cause adverse health problems. It just seems to do what manufacturers want it to do – make food look better. It’s what makes the powdered sugar coating on donuts appear so dense and snow white. Titanium dioxide gives it a boost.

And you’ve probably been consuming it for years without knowing. In the US, the Food and Drug Administration allows food products to contain up to 1% food-grade titanium dioxide without the need to include it on the ingredient label. Help yourself to a slice of bread, a bar of chocolate, a spoonful of mayonnaise or a donut, and chances are you’ll be eating a small amount of the substance.

Andrew goes on to describe the concerns that groups such as You As Sow have (Note: Links have been removed),

For some years now, researchers have recognized that some powders become more toxic the smaller the individual particles are, and titanium dioxide is no exception. Pigment grade titanium dioxide – the stuff typically used in consumer products and food – contains particles around 200 nanometers in diameter, or around one five hundredth the width of a human hair. Inhale large quantities of these titanium dioxide particles (I’m thinking “can’t see your hand in front of your face” quantities), and your lungs would begin to feel it.

If the particles are smaller though, it takes much less material to cause the same effect.

But you’d still need to inhale very large quantities of the material for it to be harmful. And while eating a powdered donut can certainly be messy, it’s highly unlikely that you’re going to end up stuck in a cloud of titanium dioxide-tinted powdered sugar coating!

… Depending on what they are made of and what shape they are, research has shown that some nanoparticles are capable of getting to parts of the body that are inaccessible to larger particles. And some particles are more chemically reactive because of their small size. Some may cause unexpected harm simply because they are small enough to throw a nano-wrench into the nano-workings of your cells.

This body of research is why organizations like As You Sow have been advocating caution in using nanoparticles in products without appropriate testing – especially in food. But the science about nanoparticles isn’t as straightforward as it seems.

As Andrew notes,

First of all, particles of the same size but made of different materials can behave in radically different ways. Assuming one type of nanoparticle is potentially harmful because of what another type does is the equivalent of avoiding apples because you’re allergic to oysters.

He describes some of the research on nano titanium dioxide (Note: Links have been removed),

… In 2004 the European Food Safety Agency carried out a comprehensive safety review of the material. After considering the available evidence on the same materials that are currently being used in products like Dunkin’ Donuts, the review panel concluded that there no evidence for safety concerns.

Most research on titanium dioxide nanoparticles has been carried out on ones that are inhaled, not ones we eat. Yet nanoparticles in the gut are a very different proposition to those that are breathed in.

Studies into the impacts of ingested nanoparticles are still in their infancy, and more research is definitely needed. Early indications are that the gastrointestinal tract is pretty good at handling small quantities of these fine particles. This stands to reason given the naturally occurring nanoparticles we inadvertently eat every day, from charred foods and soil residue on veggies and salad, to more esoteric products such as clay-baked potatoes. There’s even evidence that nanoparticles occur naturally inside the gastrointestinal tract.

He also probes the issue’s, nanoparticles, be they titanium dioxide or otherwise, and toxicity, complexity (Note: Links have been removed),

There’s a small possibility that we haven’t been looking in the right places when it comes to possible health issues. Maybe – just maybe – there could be long term health problems from this seemingly ubiquitous diet of small, insoluble particles that we just haven’t spotted yet. It’s the sort of question that scientists love to ask, because it opens up new avenues of research. It doesn’t mean that there is an issue, just that there is sufficient wiggle room in what we don’t know to ask interesting questions.

… While there is no evidence of a causal association between titanium dioxide in food and ill health, some studies – but not all by any means – suggest that large quantities of titanium dioxide nanoparticles can cause harm if they get to specific parts of the body.

For instance, there are a growing number of published studies that indicate nanometer sized titanium dioxide particles may cause DNA damage at high concentrations if it can get into cells. But while these studies demonstrate the potential for harm to occur, they lack information on how much material is needed, and under what conditions, for significant harm. And they tend to be associated with much larger quantities of material than anyone is likely to be ingesting on a regular basis.

They are also counterbalanced by studies that show no effects, indicating that there is still considerable uncertainty over the toxicity or otherwise of the material. It’s as if we’ve just discovered that paper can cause cuts, but we’re not sure yet whether this is a minor inconvenience or potentially life threatening. In the case of nanoscale titanium dioxide, it’s the classic case of “more research is needed.”

I strongly suggest reading Andrew’s post in its entirety either here on the University of Michigan website or here on The Conversation website.

Dexter Johnson in a March 11, 2015 post on his Nanoclast blog also weighs in on the discussion. He provides a very neat summary of the issues along with these observations (Note Links have been removed),

With decades of TiO2 being in our food supply and no reports of toxic reactions, it would seem that the threshold for proof is extremely high, especially when you combine the term “nano” with “asbestos”.

As You Sow makes sure to point out that asbestos is a nanoparticle. While the average diameter of an asbestos fiber is around 20 to 90 nm, their lengths varied between 200 nm and 200 micrometers.

The toxic aspect of asbestos was not its diameter, but its length. …

In addition to his summary Dexter highlights As You Sows attempt to link titanium dioxide nanoparticles to asbestos. I suggest reading his post for an informed description of what made asbestos so toxic (here) and why the linkage seems specious at this time.

For anyone interested in how As You Sow managed to introduce asbestos toxicity issues into a discussion about nano titanium dioxide and food products, there’s this from As You Sow’s FAQs (frequently asked questions) about nanomaterials in food page,

Why are nanomaterials in food important to investors?

When technology is used before ensuring that it is safe for humans and the environment, and before regulatory standards exist, companies can be exposed to significant financial, legal, and reputational risk. The limited studies that exist on nanomaterials, including nanoscale titanium dioxide*, have indicated that ingestion of these particles may pose health hazards.

The inaction of regulators does not protect companies, especially when the regulators themselves warn of the dangers of nanoparticles’ largely unknown risks. Draft guidance issued by the U.S. Food and Drug Administration raises questions about the safety of nanoparticles and demonstrates the general lack of knowledge about the technology and its effects. (1)

Asbestos litigation is a good example of the risks that can arise from using an emerging technology before it is proven safe. Use of asbestos (a nanomaterial) has created the longest, most expensive mass tort in national history with total U.S. costs now standing at over $250 billion. (2) If companies been asked to investigate and minimize or avoid risks prior to adopting asbestos technology, a sad and expensive chapter in worker harm could have been avoided.

* Titanium dioxide is a common pigment and FDA-approved food additive. It is used as a whitener, a dispersant, and a thickener.

While I don’t particularly appreciate fear-mongering as a tactic, the strategy of targeting investors and their concerns, seems to have helped As You Sow win its way.

2014 food and nanotechnologies report from the European Food Safety Authority

A Feb. 27, 2015 news item on Nanowerk announced the latest annual report on food and nanotechnologies from the European Food Safety Authority (EFSA),

In accordance with European Food Safety Authority (EFSA)’s strategy for cooperation and networking with Member States, a Network for Risk Assessment of Nanotechnologies in Food and Feed was established in 2010. The overall goals of this Network are to facilitate harmonisation of assessment practices and methodologies; to enhance exchange of information and data between EFSA and MS; and to achieve synergies in risk assessment activities. The Annual reports of the Network inform the public and the EFSA Advisory Forum about its specific activities and achievements.

The summary for the EFSA Scientific Network of Risk Assessment of Nanotechnologies in Food and Feed1 for 2014 Technical Report offers more details (Note: A link has been removed),

The Network is composed of representatives from 21 Member States and Norway. In addition, observers to this Network represent the Former Yugoslav Republic of Macedonia, Turkey and Montenegro. There is also representation from the European Commission (DGSANTE and JRC), from the EFSA Scientific Committee and the relevant Units/Panels.

During 2014, the Network followed-up on its priority areas and contributed to the making of inventory lists of applications of Nanomaterials already present in the food/feed chain.

At its 2014 meeting the Network focussed again on updates of research results from toxicological studies relevant for the oral route of exposure. Member States representatives presented relevant studies. The type of nanomaterials that are now occurring in the food/feed chain are mainly Titanium dioxide (TiO2) and Synthetic Amorphous Silica (SAS). The evidence bases for oral toxicity and for conducting comprehensive risk assessments of these two materials is building up, but more research remains needed. Challenges to draw firm risk assessment conclusions reside in (1) the intake estimation (2) the possible worst-case absorption and the dose-dependence of absorption (3) the potential irrelevance of high dose oral toxicity studies for risk assessment (4) the extrapolation of kinetic data from rat to man (5) the nanoparticle determination in tissues, and (6) the many differences between the types of nanoforms of one nanomaterial (e.g. in kinetics and toxicity). Some differences in behaviour of different nanoforms have been observed, but there is no clear overview. A new issue of concern is that absorption is not linear with dose: high dose studies are often used for tox testing for estimation of safe dose, while the high dose may result in aggregation, agglomeration, gelation and as a consequence dose-dependent absorption.

Challenges also remain to exist regarding the technical aspects for considering a material as a nanomaterial (NM) for the regulatory purpose of food labelling. The NanoDefine project (FP7) is expected to deliver by 2017 an implementable test-scheme for regulatory purposes to distinguish nano from non-nano.

The Network agreed that regardless the current challenges and regardless the % of nanoforms in the bulk material (particle size% or mass%), EFSA should assess the nano-fraction, no matter how small. Food law, as being implemented by the EFSA Panels is covering nanomaterials. Nanomaterials are addressed mainly by cross-referring to the Guidance on the risk assessment of the application of nanoscience and nanotechnologies in the food and feed chain (EFSA Scientific Committee, 2011 http://www.efsa.europa.eu/en/efsajournal/doc/2140.pdf). (p. 2 print & PDF versions)

For anyone curious about the European Food and Safety Authority, you can go here.