Food Safety: An Overview Dallas G. Hoover University of Delaware

Food safety: Traditional foods Traditional foods viewed as “safe” based on a history of use. Traditional foods can contain naturally occurring toxins present in concentrations that are not hazardous to consumers ingesting typical quantities of the food. Some traditional foods are allergenic to some consumers. Newly introduced foods produced through conventional breeding are not required to undergo safety assessment.

Foods derived from rDNA technology No evidence that hazards peculiar to the use of rDNA techniques have arisen; broad consensus among biologists that rDNA methods are safe. The same physical and biological laws govern the response of organisms modified by modern methods as those produced by classical methods. Use of rDNA methods does not result in food which is inherently less safe than that produced by conventional ones.

Safety evaluation Concern should be on properties of the food, not the method by which it was produced. Substantial equivalence: Comparison of rDNA-derived food with its traditional counterpart Used to structure safety assessment Includes evaluation of phenotypic and compositional characteristics Considers intentional and unintentional effects

Safety of introduced genetic material Characterization of genetic construct source of genetic materials size of genetic construct number of copies inserted location of insertion base sequence

Safety of gene product Composition and structure of gene product Amount expressed in food Comparison to known toxins and antinutritional factors, allergens & other functional proteins Determination of thermal and digestive stability

Unintended effects Observed infrequently in conventional breeding Expected to occur less frequently with use of rDNA techniques No scientific evidence of the occurrence of such unintended effects in foods derived from rDNA technology

Lenape and Atlantic potatoes Although infrequently observed in crosses involving conventional plant breeding, source of a toxic constituent can typically be traced back to a related species. Case of conventionally bred Lenape potato, which had to be withdrawn due to unusually high glycoalkaloid content. Attributed to use of wild, nontuber-bearing Solanum chacoense in its parentage, even though Lenape is a parent of Atlantic, a currently edible commercial potato variety.

Allergenicity FDA assessment based on source of gene(s) amino acid sequence homology of newly introduced protein(s) to known allergens immunochemical reactivity of protein(s) physicochemical properties of introduced protein (e.g., digestive stability)

rDNA soybeans & Brazil nut protein A high-methionine protein from Brazil nut was introduced into soybeans to correct the inherent methionine deficiency in soybeans. Protein shown to bind to IgE from sera of Brazil nut-allergic individuals and to elicit positive skin-prick tests. Protein identified as a major allergen; this variety of soybean never commercialized.

Factors affecting food safety perceptions of genetically engineered foods Fear of the unknown; apprehension of what is not understood; educational issues. Lack of visible effects. Effectiveness of anti-biotech and anti-globalization websites. In Europe: Mad Cow Disease Monsanto remarks Distrust leading to a “brain drain” and concern towards other technologies.

What is genetic modification? Genetic methods are a dynamic blend of “old” and “new”, ever changing. Modern agriculture is 10,000-years old. Selection, hybridization, Mendelian genetics, quantitative genetics, induced mutation, broad crosses, cell & tissue culture (fusion & somoclonal variation), embryo rescue, computerized data management, gene transformation and molecular genetics (rDNA technology).

L-tryptophan poisonings In 1989, 37 people died of eosinophilia-myalgia syndrome from consumption of L- tryptophan. Japanese manufacturer had made changes to fermentative production process (purification steps were altered, reverse osmosis removed, and activated charcoal usage reduced) resulting in toxic chemical contaminants in the nutrient. On occasion, has been incorrectly attributed to rDNA-engineered Bacillus amyloliquefacians.

Bt toxin and Starlink Bt toxin from Bacillus thuringiensis. Different Bt toxins available with different insect target spectra. Cry protein in animal feed-approved corn but not approved for human consumption. Accidentally included in taco shells, etc. A regulatory issue, not a safety issue.

Safe products on the market Food enzymes: chymosin (cheese-making), lactase (lactose hydrolysis in dairy products), α-amylase and amyloglucosidase (HFCS in soft drinks, etc.), and maltogenic α-amylase (in bread-making). Bt corn and other Bt applications. Pesticide-resistant crops. BST milk.

In closing rDNA techniques represent an important advance in food technology. rDNA technology will not solve all the world’s problems concerning hunger and disease, but it will help. For this technology to be properly used, it must be accepted; there is a clear need for increased understanding of the science and the regulations governing the science.