Both organic and conventionally produced foods present consumers with trade-offs in terms of food safety and nutritional content, a UC Davis food toxicologist says.

"While there is a growing body of research demonstrating the qualitative differences between organic and conventional foods, it is premature to conclude that either system of food production is superior to the other," said Carl Winter, director of the university's FoodSafe Program. His peer-reviewed findings were published in the December issue of the Journal of Food Science.

Surveys indicate that many consumers think organically produced foods are more nutritious and healthful. One survey found that consumers also are choosing organic foods to avoid pesticide residues and genetically modified foods.

Winter notes that while organic fruits and vegetables carry fewer pesticide residues, the produce does not necessarily come with less health risk. Research has shown that in some cases organic foods contain higher levels of naturally occurring chemical compounds -- including both health-promoting antioxidants and naturally occurring toxins that might be of concern for human health.

Winter points out that animal manure fertilizer -- used frequently in organic farming and, to a lesser extent, in conventional farming -- can pose an increased threat of microbiological contamination. He notes that certified organic production requires the composting of animal manure in a manner aimed at preventing microbial contamination, while conventional food production has no such standard.

One comprehensive study indicated that certified organic produce did not pose a higher microbiological risk than conventionally produced food crops.

Winter notes mixed findings in the area of microbial safety and animal-based foods. However, he notes that the prohibition of antibiotic use in organic animal production seems to result in a lower incidence of resistance to antimicrobial drugs among organically raised animals than among animals raised conventionally.