Food Safety: An Overview

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

2. 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.

3. 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.

4. 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

5. 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

6. 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

7. 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

8. 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 • Case of conventionally bred Lenape potato, which had to be withdrawn due to unusually high glycoalkaloid content.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.

9. 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)

10. 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.

11. 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.

12. 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).

13. 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.

14. 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.

15. 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.

16. 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.