Nanoscale Particles in Food and Food Packaging

Abstract

In a letter to the editor in the last issue, Card and Magnuson (2009) proposed that the Journal of Food Science (JFS) consider, “a set of minimum parameters be determined and reported for nanomaterials that are used in experiments assessing various biological activities, including toxicity.” This proposal is welcomed because Nanoscale Food Science, Engineering, and Technology are evolving fields and there are concerns regarding nanoscale particles in food. While we should acknowledge those concerns, we emphasize that our responses to them can only be based on either new experimental evidence or known regulatory practices. In the field of nanoscale technology, the predominant activity is with non-food engineered particles, which may be classified, as per the U.S. National Academies, under: metal oxides, nanoclays, nanotubes, and quantum dots (Sandoval 2009). It is noted that the Food and Drug Administration (FDA) has not proposed a classification system. Because engineered nanoscale particles can exhibit fundamentally different properties than the same material in bulk form, often they are treated as being different; specifically, while the small particle size contributes unique material properties, it is also the main reason for health concerns (Sandoval 2009). JFS publishes results of research work. To assure transparency, appropriateness and accuracy of the research work reported, each manuscript is peer-reviewed to assure that anyone can independently perform the research and try to reproduce the results. However, reviewers are not expected to have regulatory knowledge. The known and projected applications of nanoscale technology for the food sector may be divided into 4 categories (Chaudhry and others 2008): (1) food ingredients that are processed or created to form nanostructures, (2) additives of encapsulated or engineered nanoscale particles used in food, (3) nanoscale materials that have been incorporated to develop new food packaging, and (4) nanoscale technology-based devices and materials used in applications such as, filtration (‘nanofiltration’), water treatment, and sensors for food safety and traceability. We note that many food components exist naturally as nanoscale structures; proteins (for example, bovine serum albumin, β-lactoglobulin) have dimensions of a few nanometers. Indeed, human milk is full of nanoscale particles and this alone would suggest that “just being small” is not a reason to view a food material as being suspect. Also, many carbohydrates and lipids are linear polymers that are one-dimensional nanoscale structures with less than one nm thickness (IFST 2006). In addition, the nanoscale particles in categories 1 and 2 are likely to have been prepared either from foods currently being consumed that are, in the parlance of the FDA, “whole foods,” or from substances generally recognized as safe (GRAS) (see for example, Weiss and others 2006). However, as Sandoval (2009) noted, FDA's GRAS listings do not mention particle size, and the listings were likely to have been made without nanoscale safety evaluations. One exception to the whole foods-derived and GRAS substances criteria is that nanoscale silver particles have been shown to have strong antimicrobial characteristics. As Chaudhry and others (2008) noted, the main health risk to consumers is exposure, especially by ingestion, to nanoscale non-food particles, such as metal oxides, likely due to migration of the particles from food packaging into foods and drinks. They also noted that nanoscale technology-derived food packaging materials are the largest category of current nanoscale technology applications in the food sector. The same concerns may be attributed to using filters and sensors made from non-food nanoscale structures in the food sector. While a number of possible consumer health implications may be imagined from the consumption of foods and drinks containing non-food nanoscale particles, there do not seem to be research studies to verify them. The potential effects, especially toxicological, of many non-food nanoscale particles as they pass through the gastrointestinal route are largely unknown. Unless required by the FDA, it is unlikely that toxicological tests would be performed on nanoscale particles prepared from whole foods and GRAS substances. However, they are likely to be performed on the non-food nanoscale particles contained in packaging, filters, and sensors, and the parameters suggested by Card and Magnuson would be applicable in these studies. In addition to toxicological studies, in order to gain public acceptance of nanoscale technology-based products, ethical, legal, and social issues of the technology may need to be addressed (Mody 2008). I thank Allen Foegeding and Jochen Weiss for helpful comments.