Category Archives: food

Inhibiting pathogens in meat with edible antimicrobial films

Food poisoning is, at best, unpleasant and, at worst, lethal, so anything which helps people and other animals to avoid that condition is to be lauded, assuming there are no significant shortcomings with the solution to avoiding bad meat. According to a May 4, 2014 news item on Nanowerk a team at Penn (Pennsylvania) State University has developed an antimicrobial, edible film which may help solve the problem,

Antimicrobial agents incorporated into edible films applied to foods to seal in flavor, freshness and color can improve the microbiological safety of meats, according to researchers in Penn State’s College of Agricultural Sciences.

Using films made of pullulan — an edible, mostly tasteless, transparent polymer produced by the fungus Aureobasidium pulluns — researchers evaluated the effectiveness of films containing essential oils derived from rosemary, oregano and nanoparticles against foodborne pathogens associated with meat and poultry.

A May 1, 2014 Penn State University news release by Jeff Mulhollem, which originated the news item, describes the research in further detail,

In the study, which was published online in the April issue of the Journal of Food Science, researchers determined survivability of bacterial pathogens after treatment with 2 percent oregano essential oil, 2 percent rosemary essential oil, zinc oxide nanoparticles or silver nanoparticles.

The compounds then were incorporated into edible films made from pullulan, and the researchers determined the antimicrobial activity of these films against bacterial pathogens inoculated onto petri dishes.

Finally, the researchers experimentally inoculated fresh and ready-to-eat meat and poultry products with bacterial pathogens, treated them with the pullulan films containing the essential oils and nanoparticles, vacuum packaged, and then evaluated for bacterial growth following refrigerated storage for up to three weeks.

“The results from this study demonstrated that edible films made frompullulan and incorporated with essential oils or nanoparticles have the potential to improve the safety of refrigerated, fresh or further-processed meat and poultry products,” said Cutter. “The research shows that we can apply these food-grade films and have them do double duty — releasing antimicrobials and imparting characteristics to protect and improve food we eat.”

The edible films are a novelbut effective way to deliver antimicrobial agents to meats, Cutter explained, because the bacteria-killing action is longer lasting. Liquid applications run off the surface, are not absorbed and are less effective. The pullulan films adhere to the meat, allowing the incorporated antimicrobials to slowly dissolve, providing immediate and sustained kill of bacteria. In addition, the microorganisms do not have the opportunity to regrow.

There’s at least one problem with the pullulan films and its not, as far as the researcher is concerned, the silver or zinc oxide nanoparticles (from the news release),

Cutter conceded that pullulan films are not as oxygen-impermeable as plastic packaging now used to package meats, so the edible films are not likely to replace that material.

“The meat industry likes the properties of the polyethylene vacuum packaging materials that they are using now,” she said. “However, the one thing I really want to be able to do in the next few years is to figure out a way to co-extrude antimicrobial, edible films with the polyethylene so we have the true oxygen barrier properties of the plastic with the antimicrobial properties of the edible film.”

Knowing that edible films can release antimicrobials slowly over time and keep bacteria in meat at bay, further research will be aimed at creating what Cutter referred to as “active packaging” — polyethylene film with antimicrobial properties.

“Right now, we have two different packaging materials that are not necessarily compatible, leading to a two-step process. I keep thinking there’s a way to extrude edible, antimicrobial film in one layer with polyethylene, creating all-in-one packaging.

“The chemistry of binding the two together is the challenge, but we need to find a way to do it because marrying the two materials together in packaging would make foods — especially meat and poultry — safer to eat.”

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

Incorporation of Essential Oils and Nanoparticles in Pullulan Films to Control Foodborne Pathogens on Meat and Poultry Products by Mohamed K. Morsy, Hassan H. Khalaf, Ashraf M. Sharoba, Hassan H. El-Tanahi and Catherine N. Cutter. Journal of Food Science, April 2014, Volume 79, Issue 4, pages M675–M684. DOI: 10.1111/1750-3841.12400 Article first published online: 12 MAR 2014

© 2014 Institute of Food Technologists®

This is behind a paywall.

Nanocellulose from sugarcane?

Iran adds to this blog’s growing catalogue of plant materials from which nanocellulose can be derived. From an April 27, 2014 news item on Nanowerk,

Researchers from University of Tehran utilized sugarcane waste to produce nanocomposite film (“All-cellulose nanocomposite film made from bagasse cellulose nanofibers for food packaging application”).

The product has unique physical and mechanical properties and has many applications in packaging, glue making, medicine and electronic industries.

An April 28, 2014 Iran Nanotechnology Initiative Council (INIC) news release, which originated the news item, describes the advantages of this potential product and the research that led to it,

These nanofibers have simpler, faster and more cost-effective production method in comparison with other production methods. The size of the produced cellulose nanofiber has been reported about 39±13 nm while tension resistant of the nanocomposite produced from the nanofibers has been reported about 140 MPa. The produced nanocomposite has higher strength in comparison with the majority of biodegradable and non-biodegradable films. It seems that the produced nanocomposite can be considered an appropriate option for the elimination of artificial polymers and oil derivatives from packaging materials.

In order to produce the product, cellulose fibers were produced through mechanical milling method after separation and purification of cellulose from sugarcane bagasse, and then nanopapers were produced. Next, full cellulose nanocomposite was produced through partial dissolving method, and its characteristics were evaluated.

Results showed that as the time of partial dissolving increases, the diffusivity of the nanocomposite into vapor decreases due to the increase in glassy part (amorphous) to crystalline part. However, thermal resistant decreases as the time of partial dissolving increases because a decrease is observed in the crystalline part.

In addition, when cellulose microfibers turn into nanofibers, resistance against the tension of the produced films increases. The researchers believe that the reason for the increase is the reduction in fault points (points that lead to the fracture in cellulose fibers), increase in specific area, and integrity of nanofibers. Transparency of samples significantly increases as the size of particles decreases to nanometric scale.

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

All-cellulose nanocomposite film made from bagasse cellulose nanofibers for food packaging application by Moein Ghaderi, Mohammad Mousavi, Hossein Yousefi, & Mohsen Labbafi. Carbohydrate Polymers, vol. 104, issue 1, January 2014, pp. 59-65 http://dx.doi.org/10.1016/j.carbpol.2014.01.013

This paper is behind a paywall.

How do you know that’s extra virgin olive oil?

Who guarantees that expensive olive oil isn’t counterfeit or adulterated? An invisible label, developed by ETH researchers, could perform this task. The tag consists of tiny magnetic DNA particles encapsulated in a silica casing and mixed with the oil.

So starts Barbara Vonarburg’s April 24, 2014 ETH Zurich (Swiss Federal Institute of Technology or Eidgenössische Technische Hochschule Zürich) news release (also on EurekAlert). She goes on to describe the scope of the situation regarding counterfeit foods,

The worldwide need for anti-counterfeiting labels for food is substantial. In a joint operation in December 2013 and January 2014, Interpol and Europol confiscated more than 1,200 tonnes of counterfeit or substandard food and almost 430,000 litres of counterfeit beverages. The illegal trade is run by organised criminal groups that generate millions in profits, say the authorities. The confiscated goods also included more than 131,000 litres of oil and vinegar.

Jon Henley’s Jan. 4, 2012 article for the UK’s Guardian provides more insight into the specifics of counterfeit olive oil (Note: A link has been removed),

Last month [December 2011], the Olive Oil Times reported that two Spanish businessmen had been sentenced to two years in prison in Cordoba for selling hundreds of thousands of litres of supposedly extra virgin olive oil that was, in fact, a mixture of 70-80% sunflower oil and 20-30% olive.

… So with a litre of supermarket extra virgin costing up to £4, and connoisseurs willing to pay 10 times that sum for a far smaller bottle of seasonal, first cold stone pressed, single estate, artisan-milled oil from Italy or Greece, can we be sure of getting what we’re paying for?

The answer, according to Tom Mueller in a book out this month [January 2012], is very often not. In Extra Virginity: the Sublime and Scandalous World of Olive Oil, Mueller, an American who lives in Italy, lays bare the workings of an industry prey, he argues, to hi-tech, industrial-scale fraud. The problem, he says, is that good olive oil is difficult, time-consuming and expensive to make, but easy, quick and cheap to doctor.

Most commonly, it seems, extra virgin oil is mixed with a lower grade olive oil, often not from the same country. Sometimes, another vegetable oil such as colza or canola is used. The resulting blend is then chemically coloured, flavoured and deodorised, and sold as extra-virgin to a producer. Almost any brand can, in theory, be susceptible: major names such as Bertolli (then owned by Unilever [see Henley's article for details about the 2008 Italian olive oil scandal]) have found themselves in court having to argue, successfully in this instance, that they had themselves been defrauded by their supplier.

Meanwhile, the chemical tests that should by law be performed by exporters of extra virgin oil before it can be labelled and sold as such can often fail to detect adulterated oil, particularly when it has been mixed with products such as deodorised, lower-grade olive oil in a sophisticated modern refinery.

Given the benefits claimed for olive oil, I imagine lower grade olive oil which is more highly processed or, worse yet, a completely different kind of oil would diminish or, possibly, eliminate any potential health benefit.

Getting back to the ETH Zurich news release, here’s more about the anti-counterfeiting ‘label’,

Just a few grams of the new substance are enough to tag [label] the entire olive oil production of Italy. If counterfeiting were suspected, the particles added at the place of origin could be extracted from the oil and analysed, enabling a definitive identification of the producer. “The method is equivalent to a label that cannot be removed,” says Robert Grass, lecturer in the Department of Chemistry and Applied Biosciences at ETH Zurich.

A forgery-proof label should not only be invisible but also safe, robust, cheap and easy to detect. To fulfil these criteria ETH researchers used nanotechnology and nature’s information storehouse, DNA. A piece of artificial genetic material is the heart of the mini-label. “With DNA, there are millions of options that can be used as codes,” says Grass. Moreover, the material has an extremely low detection limit, so tiny amounts are sufficient for labelling purposes.

However, DNA also has some disadvantages. If the material is used as an information carrier outside a living organism, it cannot repair itself and is susceptible to light, temperature fluctuations and chemicals. Thus, the researchers used a silica coating to protect the DNA, creating a kind of synthetic fossil. The casing represents a physical barrier that protects the DNA against chemical attacks and completely isolates it from the external environment – a situation that mimics that of natural fossils, write the researchers in their paper, which has been published in the journal ACS Nano. To ensure that the particles can be fished out of the oil as quickly and simply as possible, Grass and his team employed another trick: they magnetised the tag by attaching iron oxide nanoparticles.

Experiments in the lab showed that the tiny tags dispersed well in the oil and did not result in any visual changes. They also remained stable when heated and weathered an ageing trial unscathed. The magnetic iron oxide, meanwhile, made it easy to extract the particles from the oil. The DNA was recovered using a fluoride-based solution and analysed by PCR, a standard method that can be carried out today by any medical lab at minimal expense. “Unbelievably small quantities of particles down to a millionth of a gram per litre and a tiny volume of a thousandth of a litre were enough to carry out the authenticity tests for the oil products,” write the researchers. The method also made it possible to detect adulteration: if the concentration of nanoparticles does not match the original value, other oil – presumably substandard – must have been added. The cost of label manufacture should be approximately 0.02 cents per litre.

The researchers have plans for other products that could benefit from this technology and answers to questions about whether or not people would be willing to ingest a label/tag along with their olive oil,

Petrol could also be tagged using this method and the technology could be used in the cosmetics industry as well. In trials the researchers also successfully tagged expensive Bergamot essential oil, which is used as a raw material in perfumes. Nevertheless, Grass sees the greatest potential for the use of invisible labels in the food industry. But will consumers buy expensive ‘extra-virgin’ olive oil when synthetic DNA nanoparticles are floating around in it? “These are things that we already ingest today,” says Grass. Silica particles are present in ketchup and orange juice, among other products, and iron oxide is permitted as a food additive E172.

To promote acceptance, natural genetic material could be used in place of synthetic DNA; for instance, from exotic tomatoes or pineapples, of which there are a great variety – but also from any other fruit or vegetable that is a part of our diet. Of course, the new technology must yield benefits that far outweigh any risks, says Grass. He concedes that as the inventor of the method, he might not be entirely impartial. “But I need to know where food comes from and how pure it is.” In the case of adulterated goods, there is no way of knowing what’s inside. “So I prefer to know which particles have been intentionally added.”

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

Magnetically Recoverable, Thermostable, Hydrophobic DNA/Silica Encapsulates and Their Application as Invisible Oil Tags by Michela Puddu , Daniela Paunescu , Wendelin J. Stark , and Robert N. Grass. ACS Nano, 2014, 8 (3), pp 2677–2685 DOI: 10.1021/nn4063853 Publication Date (Web): February 25, 2014

Copyright © 2014 American Chemical Society

This article is behind a paywall.

The Swiss aren’t the only ones interested in tagging petrol (gas), they’re already tagging petrol with nanoparticles in Malaysia with as per my Oct. 7, 2011 posting on the topic.

Food and nanotechnology (as per Popular Mechanics) and zinc oxide nanoparticles in soil (as per North Dakota State University)

I wouldn’t expect to find an article about food in a magazine titled Popular Mechanics but there it is, a Feb. 19,2014 article by Christina Ortiz (Note: A link has been removed),

For a little more than a decade, the food industry has been using nanotechnology to change the way we grow and maintain our food. The grocery chain Albertsons currently has a list of nanotech-touched foods in its home brand, ranging from cookies to cheese blends.

Nanotechnology use in food has real advantages: The technology gives producers the power to control how food looks, tastes, and even how long it lasts.

Looks Good and Good for You?

The most commonly used nanoparticle in foods is titanium dioxide. It’s used to make foods such as yogurt and coconut flakes look as white as possible, provide opacity to other food colorings, and prevent ingredients from caking up. Nanotech isn’t just about aesthetics, however. The biggest potential use for this method involves improving the nutritional value of foods.

Nano additives can enhance or prevent the absorption of certain nutrients. In an email interview with Popular Mechanics, Jonathan Brown, a research fellow at the University of Minnesota, says this method could be used to make mayonnaise less fattening by replacing fat molecules with water droplets.

I did check out US grocer, Albertson’s list of ‘nanofoods’, which they provide and discovered that it’s an undated listing on the Project of Emerging Nanotechnologies’ Consumer Products Inventory (CPI). The inventory has been revived recently after lying moribund for a few years (my Oct. 28, 2013 posting describes the fall and rise) and I believe that this 2013 CPI incarnation includes some oversight and analysis of the claims made, which the earlier version did not include. Given that the Albertson’s list is undated it’s difficult to assess the accuracy of the claims regarding the foodstuffs.

If you haven’t read about nanotechnology and food before, the Ortiz article provides a relatively even-handed primer although it does end on a cautionary note. In any event, it was interesting to get a bit of information about the process of ‘nanofood’ regulation in the US and other jurisdictions (from the Ortiz article),

Aside from requiring manufacturers to provide proof that nanotechnology foods are safe, the FDA has yet to implement specific testing of its own. But many countries are researching ways to balance innovation and regulation in this market. In 2012 the European Food Safety Authority (EFSA) released an annual risk assessment report outlining how the European Union is addressing the issue of nanotech in food. In Canada the Food Directorate “is taking a case-by-case approach to the safety assessment of food products containing or using nanomaterials.”

I featured the FDA’s efforts regarding regulation and ‘nanofood’ in an April 23, 2012 posting,

It looks to me like this [FDA's draft guidance for 'nanofoods'] is an attempt to develop a relationship where the industry players in the food industry to police their nanotechnology initiatives with the onus being on industry to communicate with the regulators in a continuous process, if not at the research stage certainly at the production stage.

At least one of the primary issues with any emerging technology revolves around the question of risk. Do we stop all manufacturing and development of nanotechnology-enabled food products until we’ve done the research? That question assumes that taking any risks is not worth the currently perceived benefits. The corresponding question, do we move forward and hope for the best? does get expressed perhaps not quite so baldly; I have seen material which suggests that research into risks needlessly hampers progress.

After reading on this topic for five or so years, my sense is that most people are prepared to combine the two approaches, i.e., move forward while researching possible risks. The actual conflicts seem to centre around these questions, how quickly do we move forward; how much research do we need; and what is an acceptable level of risk?

On the topic of researching the impact that nanoparticles might have on plants (food or otherwise), a January 24, 2013 North Dakota State University (NDSU) news release highlights a student researcher’s work on soil, plants, and zinc oxide nanoparticles,

NDSU senior Hannah Passolt is working on a project that is venturing into a very young field of research. The study about how crops’ roots absorb a microscopic nutrient might be described as being ahead of the cutting-edge.

In a laboratory of NDSU’s Wet Ecosystem Research Group, in collaboration with plant sciences, Passolt is exploring how two varieties of wheat take up extremely tiny pieces of zinc, called nanoparticles, from the soil.

As a point of reference, the particles Passolt is examining are measured at below 30 nanometers. A nanometer is 1 billionth of a meter.

“It’s the mystery of nanoparticles that is fascinating to me,” explained the zoology major from Fargo. “The behavior of nanoparticles in the environment is largely unknown as it is a very new, exciting science. This type of project has never been done before.”

In Passolt’s research project, plants supplied by NDSU wheat breeders are grown in a hydroponic solution, with different amounts of zinc oxide nanoparticles introduced into the solution.

Compared to naturally occurring zinc, engineered zinc nanoparticles can have very different properties. They can be highly reactive, meaning they can injure cells and tissues, and may cause genetic damage. The plants are carefully observed for any changes in growth rate and appearance. When the plants are harvested, researchers will analyze them for actual zinc content.

“Zinc is essential for a plant’s development. However, in excess, it can be harmful,” Passolt said. “In one of my experiments, we are using low and high levels of zinc, and the high concentrations are showing detrimental effects. However, we will have to analyze the plants for zinc concentrations to see if there have been any effects from the zinc nanoparticles.”

Passolt has conducted undergraduate research with the Wet Ecosystem Research Group for the past two years. She said working side-by-side with Donna Jacob, research assistant professor of biological sciences; Marinus Otte; professor of biological sciences; and Mohamed Mergoum, professor of plant sciences, has proven to be challenging, invigorating and rewarding.

“I’ve gained an incredible skill set – my research experience has built upon itself. I’ve gotten to the point where I have a pretty big role in an important study. To me, that is invaluable,” Passolt said. “To put effort into something that goes for the greater good of science is a very important lesson to learn.”

According to Jacob, Passolt volunteered two years ago, and she has since become an important member of the group. She has assisted graduate students and worked on her own small project, the results of which she presented at regional and international scientific conferences. “We offered her this large, complex experiment, and she’s really taken charge,” Jacob said, noting Passolt assisted with the project’s design, handled care of the plants and applied the treatments. When the project is completed, Passolt will publish a peer-reviewed scientific article.

“There is nothing like working on your own experiment to fully understand science,” Jacob said. “Since coming to NDSU in 2006, the Wet Ecosystem Research Group has worked with more than 50 undergraduates, possible only because of significant support from the North Dakota IDeA Networks of Biomedical Research Excellence program, known as INBRE, of the NIH National Center for Research Resources.”

Jacob said seven undergraduate students from the lab have worked on their own research projects and presented their work at conferences. Two articles, so far, have been published by undergraduate co-authors. “I believe the students gain valuable experience and an understanding of what scientists really do during fieldwork and in the laboratory,” Jacob said. “They see it is vastly different from book learning, and that scientists use creativity and ingenuity daily. I hope they come away from their experience with some excitement about research, in addition to a better resume.”

Passolt anticipates the results of her work could be used in a broader view of our ecosystem. She notes zinc nanoparticles are an often-used ingredient in such products as lotions, sunscreens and certain drug delivery systems. “Zinc nanoparticles are being introduced into the environment,” she said. “It gets to plants at some point, so we want to see if zinc nanoparticles have a positive or negative effect, or no effect at all.”

Researching nanoparticles the effects they might have on the environment and on health is a complex process as there are many types of nanoparticles some of which have been engineered and some of which occur naturally, silver nanoparticles being a prime example of both engineered and naturally occurring nanoparticles. (As well, the risks may lie more with interactions between nanomaterials.) For an example of research, which seems similar to the NDSU effort, there’s this open access research article,

Low Concentrations of Silver Nanoparticles in Biosolids Cause Adverse Ecosystem Responses under Realistic Field Scenario by Benjamin P. Colman, Christina L. Arnaout, Sarah Anciaux, Claudia K. Gunsch, Michael F. Hochella Jr, Bojeong Kim, Gregory V. Lowry,  Bonnie M. McGill, Brian C. Reinsch, Curtis J. Richardson, Jason M. Unrine, Justin P. Wright, Liyan Yin, and Emily S. Bernhardt. PLoS ONE 2013; 8 (2): e57189 DOI: 10.1371/journal.pone.0057189

One last comment, the Wet Ecosystem Research Group (WERG) mentioned in the news release about Passolt has an interesting history (from the homepage; Note: Links have been removed),

Marinus Otte and Donna Jacob brought WERG to the Department of Biological Sciences in the Fall of 2006.  Prior to that, the research group had been going strong at University College Dublin, Ireland, since 1992.

The aims for the research group are to train graduate and undergraduate students in scientific research, particularly wetlands, plants, biogeochemistry, watershed ecology and metals in the environment.  WERG research  covers a wide range of scales, from microscopic (e.g. biogeochemical processes in the rhizosphere of plants) to landscape (e.g. chemical and ecological connectivity between prairie potholes across North Dakota).  Regardless of the scale, the central theme is biogeochemistry and the interactions between multiple elements in wet environments.

The group works to collaborate with a variety of researchers, including soil scientists, geologists, environmental engineers, microbiologists, as well as with groups underpinning management of natural resources, such the Minnesota Department of Natural Resources, the Department of Natural Resources of Red Lake Indian Reservation, and the North Dakota Department of Health, Division of Water Quality.

Currently, WERG has several projects, mostly in North Dakota and Minnesota.  Otte and Jacob are also Co-directors of the North Dakota INBRE Metal Analysis Core, providing laboratory facilities and mentoring for researchers in undergraduate colleges throughout the state. Otte and Jacob are also members of the Upper Midwest Aerospace Consortium.

Beer drinkers weep into their pints on hearing news of electronic tongue

First, it was the wine drinkers (my July 28, 2011 posting titled: Bio-inspired electronic tongue replaces sommelier? about research performed by Spanish researches at the UAB (Universitat Autònoma de Barcelona) now, these researchers have turned their attention to beer.  From a Jan. 30, 2014 news release on EurekAlert,

Beer is the oldest and most widely consumed alcoholic drink in the world. Now, scientists at the Autonomous University of Barcelona have led a study which analysed several brands of beer by applying a new concept in analysis systems, known as an electronic tongue, the idea for which is based on the human sense of taste.

As Manel del Valle, the main author of the study, explains to SINC [Spain's state public agency specialising in science, technology and innovation information]: “The concept of the electronic tongue consists in using a generic array of sensors, in other words with generic response to the various chemical compounds involved, which generate a varied spectrum of information with advanced tools for processing, pattern recognition and even artificial neural networks.”

In this case, the array of sensors was formed of 21 ion-selective electrodes, including some with response to cations (ammonium, sodium), others with response to anions (nitrate, chloride, etc.), as well as electrodes with generic (unspecified) response to the varieties considered.

The authors recorded the multidimensional response generated by the array of sensors and how this was influenced by the type of beer considered. An initial analysis enabled them to change coordinates to view the grouping better, although it was not effective for classifying the beers.

“Using more powerful tools – supervised learning – and linear discriminant analysis did enable us to distinguish between the main categories of beer we studied: Schwarzbier, lager, double malt, Pilsen, Alsatian and low-alcohol,” Del Valle continues, “and with a success rate of 81.9%.”

It seems the electronic tongue does have one drawback,

Furthermore, it is worth noting that varieties of beers that the tongue is not trained to recognise, such as beer/soft drink mixes or foreign makes, were not identified (discrepant samples), which, according to the experts, validates the system as it does not recognise brands for which it was not trained.

Future plans, according to the news release, include,

In view of the ordering of the varieties, which followed their declared alcohol content, the scientists estimated this content with a numerical model developed with an artificial neural network.

“This application could be considered a sensor by software, as the ethanol present does not respond directly to the sensors used, which only respond to the ions present in the solution,” outlines the researcher.

The study concludes that these tools could one day give robots a sense of taste, and even supplant panels of tasters in the food industry to improve the quality and reliability of products for consumption.

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

Beer classification by means of a potentiometric electronic tongue by Xavier Cetó, Manuel Gutiérrez-Capitán, Daniel Calvo , and Manel del Vall. Food Chemistry Volume 141, Issue 3, 1 December 2013, Pages 2533–2540 DOI: 10.1016/j.foodchem.2013.05.091

I’d imagine that anyone who has dreams of becoming a beer taster might want to consider some future alternatives. As for folks like Canadian Kevin Brauch, “host of The Thirsty Traveler [on the Cooking Channel], …  about the world’s greatest beer, wine and cocktails,” he will no doubt claim that a robot is not likely to express like/dislikes or more nuanced opinions, should he become aware of his competitor. Besides, Brauch does have the cocktail to rely on; there’s no word of cocktails being test on an electronic tongue, not yer.

Historically, Canada has been a beer drinkers nation. According to data collected in 2010, we rank fifth in the world (following the Czech Republic, Germany, Austria, and Ireland, in that order)  found in the Wikipedia essay: List of countries by beer consumption per capita.  For anyone who’s curious about Canadian beer drinkers’ perspectives, I found this blog, The Great Canadian Beer Snob (as of 2012 the blog owner, Matt Williams lived in Victoria, BC), which I suspect was a name chosen with tongue-in-cheek.

Biochemical fate of nanoemulsion-based food delivery systems in the gastrointestinal tract

This is a story about nutraceuticals or, more specifically, about nanotechnology and food according to a Jan. 20, 2014 news item on Azonano,

Food scientist Hang Xiao of the University of Massachusetts Amherst recently received a four-year, $491,220 grant to study the biochemical fate of nanoemulsion-based food delivery systems in the gastrointestinal (GI) tract, hoping to re-shape them and enhance the absorption of beneficial food components encapsulated in delivery systems.

Food biochemists like Xiao believe that if taken up in appropriate amounts and forms, certain food components known as nutraceuticals might benefit human health by providing anti-inflammatory or anti-cancer effects. Nutraceuticals include flavonoids and carotenoids in fruits and vegetables, for example.

This project, supported by the U.S. Department of Agriculture’s National Institute of Food and Agriculture, will focus on manipulating the structure and composition of nano-emulsion delivery systems to modify the fate of encapsulated nutraceuticals in the GI tract to enhance their bioavailability.

A Jan. 17, 2014 news release on EurekAlert, which originated the news item, explains further,

“In the last decade, knowledge has been advancing about how to effectively deliver beneficial components in food. This research will allow us to direct the assembly of nano-emulsion droplets to create characteristics that will dictate how they are digested and absorbed,” Xiao explains. “This would be a model for nutraceutical delivery in a wide range of food products. Someday prepared foods may help lower our risk of cancer, for example.”

Specifically, using both cell culture and animal models, Xiao and colleagues will design lipid nanoparticles at three stages: From nano-emulsion droplets containing nutraceuticals, to mixed micelles and finally to chylomicrons. To start this process, digestion physiochemically disassembles nano-emulsion droplets. The resulting chemical components are then assembled into mixed micelles in the small intestine, where epithelial cells called enterocytes take them up. There they are reassembled into chylomicrons and absorbed into blood circulation through the lymph system.

The scientists want to influence the size and composition of chylomicrons, because these characteristics dictate the fate of nutraceuticals encapsulated in the chylomicrons. Certain sizes and compositions are better able to deliver nutraceuticals to the lymph system, which protects nutraceuticals from being cleared by the liver. This will enhance bioavailability of flavonoids and other beneficial compounds to the body, potentially offering health benefits.

“We’re basically utilizing what already happens in our bodies all the time, but introducing food-grade nano-emulsion systems that can influence the nature of mixed micelles as well as chylomicrons,” says Xiao. “It’s safe, it’s all digested and simply delivers beneficial food components to a greater extent than if the system was left alone.”

Given that this falls under my nanotechnology and food classification, I was reminded of a recent panel discussion on the topic held by the UK’s Guardian newspaper, from my Oct. 29, 2013 posting,

There’s no indication as to what the 25 audience members thought about the session although Hilary Sutcliffe of Matter was quoted,

Audience member Hilary Sutcliffe, director of the Matter think tank on responsible innovation, was keen to emphasise the limits of nanotechnology in food. “If we’re really lucky, we might get nanosalt and a couple of nano-encapsulated vitamins that go in products,” she told the panel, describing her disappointment in the progress of nanotechnology in food to date.

Sutcliffe explained that these limited applications are expensive and not that useful: manufacturers would rather just reduce salt content than pay for nanosalt, and vitamins and flavourings do not need to be nano-encapsulated because they can be added to foods at the microscale, rather than at the nano-level, which is one thousand times smaller.

She also suggested that, so far, the possible uses of nanotechnology have only been in Western diets and that people should be realistic about its use for tackling the impending global food crisis. “Nothing about nanotechnology is in relation to anything except Western, expensive foods that are slightly gratuitous and not particularly necessary,” she said, before adding that it is not currently helping to feed the world. “If you are going to talk about feeding the world, be brave, take on GM, let’s have that discussion.”

I was not able to find notice of any US public engagement sessions on the topic of ‘nano and food’. If you know of any such sessions, please do share in the comments section.

Nano info on food labels wanted by public in the US?

There’s some social science research about nanotechnology and food labeling in the US making its rounds on the internet. From an Oct. 28, 2013 news item on Nanowerk (Note: A link has been removed),

New research from North Carolina State University and the University of Minnesota finds that people in the United States want labels on food products that use nanotechnology – whether the nanotechnology is in the food or is used in food packaging. The research (“Hungry for Information: Public Attitudes Toward Food Nanotechnology and Labeling”) also shows that many people are willing to pay more for the labeling.

Study participants were particularly supportive of labeling for products in which nanotechnology had been added to the food itself, though they were also in favor of labeling products in which nanotechnology had only been incorporated into the food packaging.

The Oct. 28, 2013 North Carolina State University (NCSU) news release (also on EurekAlert), which originated the news item, has a title that can be viewed as misleading  especially in light of how other news media have interpreted it,

Public wants labels for food nanotech — and they’re willing to pay for it

Yes but it’s not exactly ‘the public’ (from the news release),

“We wanted to know whether people want nanotechnology in food to be labeled, and the vast majority of the participants in our study do,” says Dr. Jennifer Kuzma, senior author of a paper on the research and Goodnight-Glaxo Wellcome Distinguished Professor of Public Administration at NC State. “Our study is the first research in the U.S. to take an in-depth, focus group approach to understanding the public perception of nanotechnology in foods.” [emphasis mine]

The researchers convened six focus groups – three in Minnesota and three in North Carolina – and gave study participants some basic information about nanotechnology and its use in food products. Participants were then asked a series of questions addressing whether food nanotechnology should be labeled. Participants were also sent a follow-up survey within a week of their focus group meeting. [emphasis mine]

Since ‘focus group’ isn’t likely to grab attention in a headline whoever wrote the news release decided on a more dramatic approach citing the ‘public’ which resulted in this still more dramatic headline for an Oct. 29, 2013 news item on Red Orbit (Note: Links have been removed),

Most Americans Want To See Labels On Their Nanofoods

Americans overwhelmingly want to know when they are eating food products that use nanotechnology, and are happy to pay the additional labeling costs, according to a new study published this month in the journal Review of Policy Research.

“Our study is the first research in the United States to take an in-depth, focus group approach to understanding the public perception of nanotechnology in foods,” said Dr. Jennifer Kuzma of North Carolina State University, the study’ s senior author. [emphasis mine] “We wanted to know whether people want nanotechnology in food to be labeled, and the vast majority of the participants in our study do.”

Curious, I read the paper (which is open access),

Hungry for Information: Public Attitudes Toward Food Nanotechnology and Labeling by Jonathan Brown, University of Minnesota; Jennifer Kuzma, North Carolina State University. Published: Online Oct. 7 [2013] in Review of Policy Research DOI: 10.1111/ropr.12035

First off, this study is, by my standards, a well written piece of research. The writers have grounded their work in the literature,  explained their approach and methodology, and provided many appendices including one with the script used by the focus group moderators. Surprisingly, I’ve read more than one piece of ‘social science research’ which did not provide one or more of the previously mentioned aspects essential to a basic, solid research paper. In other words, there are a lot of sloppy social science research papers out there. Thankfully, this is not one of them. That said, I do have a comment about the paper’s title and a nit to pick regarding the methodology.

The paper’s title has a ‘look at me’ quality which has found its way into the news release and ultimately some of the headlines in various online publications (including this post). The paper’s title in the context of a publication called Review of Policy Research is less problematic due to its audience, i.e., policy wonks who are likely to discount the title as simply an attempt to get attention. The point is that the audience for Review of Policy Research is not likely to take that title at face value, i.e., uncritically. However, as this ‘look at me’ title is rewritten and makes its way through various media outlets, the audience changes to one that is much more likely to take it at face value.

Researchers are in a bind. They want attention for their work but can risk media coverage which distorts their findings. As for the level of distortion to be found, here’s information about the methodology and sample (participants), from the research paper,

Seven focus groups, 90 minutes in length and ranging in size from seven to ten participants, were conducted between September 2010 and January 2011 in the Minnesota cities of Minneapolis, Richfield, and Bloomington, and the North Carolina cities of Raleigh, Garner, and Cary. [emphasis mine' Cities were selected based on the main city location, the largest suburb, and finally a randomly selected city between 30,000 and 60,000 residents, all within the counties of Hennepin, Minnesota, and Wake, North Carolina.

Participants were recruited using a stratified random sample, with the goal of having equal female and male numbers in each group, while matching a demographic county profile. Those who had a prior background in or extensive knowledge of nanotechnology were excluded from participation. The profiles were based on age, sex, race, education, family household income, and ideology (liberal, moderate, and conservative) criteria and generated by means of census data in conjunction with information supplied from select city community centers. Telephone and cell phone samples for each city were acquired and used to recruit 12 participants for each focus group, with the expectation of 75 percent attendance per group. Participants were given light dinner refreshments and $100 cash for their participation.

A total of 56 participants partook in one of the seven focus groups (n1 = 8, n2 = 10, n3 = 8, n4 = 7, n5 = 8, n6 = 7, and n7  = 8). The overall demographic distribution contained more males (64 percent, n = 36) versus females (36 percent, n = 20); whites/Caucasians (84 percent, n = 47) versus blacks/African Americans (11 percent, n = 6) and Asians/Pacific Islanders (4 percent, n = 2); and those with a postgraduate or professional degree (27 percent, n = 15) versus college graduate (23 percent, n = 13), some college (16 percent, n = 9), high school graduate (14 percent, n = 8), technical college graduate (7 percent, n = 4), some high school (5 percent, n = 3), some technical college (2 percent, n = 1), and “Other” education (2 percent, n = 1). Race/ethnicity and education had n = 1 and n = 2 “No Answer” responses, respectively. The most common age bracket was 50–60 (36 percent, n = 20) compared with “Over 60” (23 percent, n = 13), 41–49 (23 percent, n = 13), 31–39 (7 percent, n = 4), and “Under 30” (7 percent, n = 4). Additionally, two provided “No Answer” for their ages.

So, 56 people, at the most. from two different states are representing Americans. Under Study Limitations subhead, the researchers outline some of their own concerns regarding this research (from the paper),

Several limitations of our focus group study are worth noting. The small sample size (n = 56 for focus groups and worksheet responses; n = 34 for postsurvey) reduces inferential power for the quantitative worksheet and postsurvey results.  Additionally, a small sample size coupled with underrepresentation for multiple demographics (e.g., non-Caucasians, females, those under age 40, and so on) restricts generalizability of results, whether quantitative or qualitative. For focus groups, however, this is to be expected as the goal is in-depth and quality discussions that explore issues heretofore under-investigated. [all emphases mine]

The nature of focus group execution presents further challenges. For example, introverted individuals may not participate as readily, and this potential imbalance skews the discussion toward the extraverted participants’ ideas. A technique to mitigate this bias, which was employed by our moderators, is to directly ask quieter participants questions once a topic is generated. Although directed calling is effective at ensuring all views on a specific topic are eventually heard, more talkative participants nonetheless exert essential control as their initial contributions determine the topics to be covered. Extraverts will thus be overrepresented in the conversation flow.

Another challenge with employing focus groups relates to moderator-controlled variations. While one discussion guide (i.e., set of specific guiding questions) was used for all focus groups (see Appendix A), the moderator frequently had to ask various follow-up questions to maintain substantive dialog. Consequently, several impromptu questions stimulating important exchanges were not raised uniformly in all groups. Fortunately, such variability was not widely problematic, as all focus groups consisted of the same six phases with the same preliminary prompts. Below we present the results from our study that relate to food and nanotechnology products and their labeling.

The results from the research are suggestive but this work does not offer proof that Americans want nano information on their food labels and are will to pay more. However this research lays the groundwork for future queries as the researchers themselves note in their Discussion at the end of the paper,

This study is the first, to our knowledge, to concentrate on public attitudes toward nanofood labeling in the United States. As such, we took an exploratory and grounded theory approach to reveal insights that could be important for developing policies and programs. Focus group discussions, in-group response worksheets, and postsurvey results from this study begin to form a picture of what people view as important for nanofood governance and labeling more specifically. Future studies will be needed to further explore these results, as there were several limitations to this study including the small sample sizes for the postsurvey (n = 34) and focus groups (n = 56) in the context of applying inferential statistics, sample underrepresentation for some demographic variables, potential overrepresentation of extroverted opinions in focus group conversations, and intergroup moderator consistency (see also the “Study Limitations” section above). These limitations are often associated with focus group research.

The researchers also describe the various themes that emerged from the focus group discussions,

Labeling discussions activated numerous topics directly and indirectly related to nanofood product labeling. Skepticism and the influence of historical experiences were two themes that emerged in this study that have not been extensively covered in previous literature on public perception of nanotechnology. Participants were skeptical concerning actions, intentions, and promised outcomes, often without reference to particular organizations or their trust of them. In part, skepticism stemmed from historical experiences with other product domains like pesticides, nutritional and allergenicity labels, and prior food safety claims. Participants relied heavily on previous experiences related to nanofood labeling in order to form opinions on this new domain.

I encourage you to read the research yourself. As these things go, this study is quite readable. However, I do have one final nit to pick, household income. While the researchers used the data to develop their stratified, random sample, they don’t seem to have taken income into account when analyzing the results or considering problems in the methodology. It seems to me that household income might be a factor in how people feel about paying more for food labels that include nano information.

This is the second nanofood-themed post I’ve published recently, see my Oct. 23, 2013 posting for a report of a food and nano panel held at the Guardian’s (newspaper) offices in London, UK>

Carbon nanotubes one way: gas and other flexible sensors

A Sept. 24, 2013 Technische Universitaet Muenchen (TUM) press release (also on EurekAlert) promises that flexible sensors are on the horizon,

Carbon nanotube-based gas sensors created at TUM offer a unique combination of characteristics that can’t be matched by any of the alternative technologies. They rapidly detect and continuously respond to extremely small changes in the concentrations of gases including ammonia, carbon dioxide, and nitrogen oxide. They operate at room temperature and consume very little power. Furthermore, as the TUM researchers report in their latest papers, such devices can be fabricated on flexible backing materials through large-area, low-cost processes.

Thus it becomes realistic to envision plastic food wrap that incorporates flexible, disposable gas sensors, providing a more meaningful indicator of food freshness than the sell-by date. Measuring carbon dioxide, for example, can help predict the shelf life of meat. “Smart packaging” – assuming consumers find it acceptable and the devices’ non-toxic nature can be demonstrated – could enhance food safety and might also vastly reduce the amount of food that is wasted. Used in a different setting, the same sort of gas sensor could make it less expensive and more practical to monitor indoor air quality in real time.

Dexter Johnson in a Sept. 26, 2013 posting on Nanoclast (an IEEE [Institute of Electrical and Electronics Engineers] blog) warns (Note: Links have been removed),

While this sounds great, the obstacle preventing this from becoming a reality has always been cost. Thin-film sensory packaging may make sense for a high-cost item, but for an inexpensive grocery store product, it’s hard to justify an additional cost that may be as much as the product itself. I made this point nearly a decade ago in report I authored titled, “The Future of Nanotechnology in Printing and Packaging”.

This doesn’t even take into account the often biased opinion people have about nanotechnology in relation to food.

Dexter recommends the researchers focus their commercialization efforts on robotic skins and other high ticket applications.

In reading the description of how the researchers created these flexible sensors, Dexter’s concerns are brought int high relief,

The most basic building block for this technology is a single cylindrical molecule, a rolled-up sheet of carbon atoms that are linked in a honeycomb pattern. This so-called carbon nanotube could be likened to an unimaginably long garden hose: a hollow tube just a nanometer or so in diameter but perhaps millions of times as long as it is wide. Individual carbon nanotubes exhibit amazing and useful properties, but in this case the researchers are more interested in what can be done with them en masse.

Laid down in thin films, randomly oriented carbon nanotubes form conductive networks that can serve as electrodes; patterned and layered films can function as sensors or transistors. “In fact,” Prof. Lugli [Prof. Paolo Lugli, director of TUM's Nanoelectronics Institute] explains, “the electrical resistivity of such films can be modulated by either an applied voltage (to provide a transistor action) or by the adsorption of gas molecules, which in turn is a signature of the gas concentration for sensor applications.” And as a basis for gas sensors in particular, carbon nanotubes combine advantages (and avoid shortcomings) of more established materials, such as polymer-based organic electronics and solid-state metal-oxide semiconductors. What has been lacking until now is a reliable, reproducible, low-cost fabrication method.

Spray deposition, supplemented if necessary by transfer printing, meets that need. An aqueous solution of carbon nanotubes looks like a bottle of black ink and can be handled in similar ways. Thus devices can be sprayed – from a computer-controlled robotic nozzle – onto virtually any kind of substrate, including large-area sheets of flexible plastic. There is no need for expensive clean-room facilities.

“To us it was important to develop an easily scalable technology platform for manufacturing large-area printed and flexible electronics based on organic semiconductors and nanomaterials,” Abdellah says. “To that end, spray deposition forms the core of our processing technology.”

Remaining technical challenges arise largely from application-specific requirements, such as the need for gas sensors to be selective as well as sensitive.

Here are citations for and links to three of the researchers’ papers,

Fabrication of carbon nanotube thin films on flexible substrates by spray deposition and transfer printing. Ahmed Abdelhalim, Alaa Abdellah, Giuseppe Scarpa, Paolo Lugli. Carbon, Vol. 61, September 2013, 72-79. DOI: 10.1016/j.carbon.2013.04.069

Flexible carbon nanotube-based gas sensors fabricated by large-scale spray deposition.
Alaa Abdellah, Zubair Ahmad, Philipp Köhler, Florin Loghin, Alexander Weise, Giuseppe Scarpa, Paolo Lugli. IEEE Sensors Journal, Vol. 13 Issue 10, October 2013, 4014-4021. DOI: 10.1109/JSEN.2013.2265775

Scalable spray deposition process for high performance carbon nanotube gas sensors. Alaa Abdellah, Ahmed Abdelhalim, Markus Horn, Giuseppe Scarpa, and Paolo Lugli. IEEE Transactions on Nanotechnology 12, 174-181, 2013. DOI: 10.1109/TNANO.2013.2238248

All three papers are behind paywalls.

In one of those coincidences that take place from time to time, I wrote about an upcoming event taking place in the Guardian’s London offices, a panel discussion on nanotechnology and food,in a Sept.  26, 2013 posting.

UK’s Guardian newspaper hosts panel discussion: Should we use nanotechnology to feed ourselves?

This can be a short one. Should you happen to be in London, UK on Wednesday, Oct. 9, 2012, you can join in a panel discussion to be held in the Guardian’s offices (registration required). Here’s more from a Sept. 22, 2013 news item on Nanowerk,

Global society faces a number of stark choices regarding how we produce and consume food. Quite simply, current practices are not sustainable for the growing global population and trends observed in emerging economies of adopting a consumer-heavy Western lifestyle. We need to change.

This panel discussion, on Wednesday, October 9, 2013 at 6 pm, chaired by The Guardian’s Science and Environment Correspondent, Alok Jha, will discuss the contribution nanotechnologies can make to this, and the potential benefits and risks that go hand-in-hand.

Full details can be found here on the event registration page on the Guardian website,

The Guardian, in association with the Nanopinion Project, are delighted to offer readers the chance to attend an evening seminar on Wednesday 9 October, held at the Guardian offices in London.

There will be a panel discussion, chaired by the Guardian’s Science and Environment Correspondent, Alok Jha, to consider the contribution nanotechnologies can make to food production and security, and the potential benefits and risks that go hand-in-hand.

The discussion will reflect on the societal impacts that new technology solutions may have and will include representatives from industry, academia, NGOs and government agencies.

We will be discussing:

• Where are nanotechnologies are being used in the food chain?

• What can we expect in the future?

• What scenarios are likely from using or not using nanotechnologies?

• What are the alternatives?

• How are things different around the globe?

• What are the impacts of different nanomaterials on the environment?

• What about consumer confidence – who has looked at this?

The discussion will then be followed by a Q&A where delegates will have the opportunity to gain further insight from our panel of experts. The seminar will be reported through the Guardian’s online channels to encourage continued discussion and awareness of the key issues among the broader public.

Simply register your details below and you could win one of 20 places to this stimulating event.

Good luck and for those who can’t be bothered to scroll up,  here’s the registration page again. One final thought, it would be nice to know who their experts will be.