Possible enhanced pesticide absorption from fresh food via nanoemulsions

University of Massachusetts Amherst food scientist David Julian McClements will lead a team that has received a three-year, $444,550 grant from the U.S. Department of Agriculture's National Institute of Food and Agriculture to study the possibility that eating food nanoemulsions found in dressings, dips or sauces might increase the amount of pesticides absorbed from co-ingested fruits and vegetables, thus increasing risk of adverse health effects.

Previously, McClements, who is recognized as one of the world's leading experts in using food nanoemulsions to deliver nutrients and nutraceuticals, and his colleagues have shown that food nanoemulsions increase the bioavailability of beneficial nutrients, vitamins and nutraceuticals. These bioactive molecules may be encapsulated within the nanoemulsions or they may be present in foods eaten along with the nanoemulsions.

However, an unintended consequence could be that the food nanoemulsions also enhance the absorption of undesirable compounds in foods such as pesticides, which may increase their toxicity.

"At present there is little information on the potential for food-grade nanoemulsions to increase the absorption of pesticides from foods, which means that it is not possible to carry out a proper risk assessment of their potential deleterious effects on human health and well-being," they note.

McClements adds, "The purpose of this project is to quantify the ability of food nanoemulsions to increase the bioavailability of pesticides from fresh fruits and vegetables, and therefore to provide information about their potential risks as well as benefits."

In addition to McClements, whose expertise is in nanoemulsion design and in vitro gastrointestinal testing, the UMass Amherst research team includes food scientists Hang Xiao, an expert in bioactives and pharmacology, and Yeonhwa Park, with expertise in pesticides and toxicity. John Clark, director of the campus's pesticide analysis laboratory, is also a co-investigator on the team.

Using in vitro gastrointestinal tract cell culture and animal models, the researchers plan to conduct experiments with nanoemulsions containing particles with differing compositions, sizes, interfacial chemistries and charge, to systematically examine the impact of the composition and structure of nanoemulsions on their ability to increase the bioavailability of common pesticides on treated fruits and vegetables. Further, they intend to establish the underlying physicochemical mechanisms involved.

McClements and colleagues point out that according to a recent USDA report, almost 60 percent of the 10,619 samples tested had detectable levels of pesticides, but in most cases the levels were below the tolerance levels established by the Environmental Protection Agency. However, a significant number of samples had levels close to or above these tolerance levels in both domestic and imported produce, and consumers are exposed to a mixture of pesticides whose health effects may be additive.

They add, "Consequently, there is some concern that long-term consumption of pesticide-treated fresh produce could cause health problems. Hence, there is a critical need for information on the types and amounts of pesticides that are actually absorbed by humans that the EPA can use in the re-registration of pesticides in the USA that is currently been carried out under the Food Quality Protection Act."

Provided by University of Massachusetts Amherst