ORGANIC VS. CONVENTIONAL FOODS: A Look at Food Safety Risks

1. ORGANIC VS. CONVENTIONAL FOODS: A Look at Food Safety Risks Dr. Carl K. Winter Department of Food Science and Technology University of California, Davis ckwinter@ucdavis.edu

2. OUTLINE Growth of organic food industry Organic food regulations and standards Comparisons of organic and conventional foods: Pesticide residues Nutritional composition Natural toxins Microbiological contamination Summary and conclusions

3. ORGANIC FOOD INDUSTRY GROWING RAPIDLY

4. Why do consumers choose organic foods? Perceived health and nutrition benefits Avoidance of pesticides (70%) Freshness (68%) Health and nutrition (67%) Avoidance of genetically modified foods (55%) Willing to pay typical 10% to 40% price premiums

5. ORGANIC FOODS: Not just fresh fruits and vegetables anymore

6. ORGANIC REGULATIONS AND PRACTICES Systems based on minimal use of off-farm inputs and on management practices that restore, maintain, and enhance ecological harmony. Ecological production systems that promote and enhance biodiversity, biological cycles, and soil biological activity.

7. ORGANIC REGULATIONS AND PRACTICES Prohibited in organic production: Synthetic pesticides Growth hormones Antibiotics Genetically modified crops Irradiation Chemical fertilizers Sewage sludge

8. ORGANIC REGULATIONS AND PRACTICES Synthetic materials only allowed if they are on the National List of Allowed and Approved Substances Typically naturally-occurring Some EPA-approved pesticides are allowed in organic production (i.e. sulfur, chrysanthemum extracts)

9. ORGANIC REGULATIONS AND PRACTICES Conversion from conventional to organic agriculture takes time Fields cannot be certified for organic production until 3 years have elapsed since last use of prohibited substances Animal herds - must be fed 80% organic feeds for 9 months and then 100% organic feeds for another 3 months

10. REGULATORY TIMELINE 1990 - Organic Foods Production Act (OPFA) introduced by USDA 2000 - National Organic Program Standards announced 2002 - National Organic Program Standards fully implemented USDA Secretary Glickman: �organic certification expresses a production philosophy and organic labeling did not imply a superior, safer, or healthier product than food not labeled as organic�

11. ORGANIC SEAL

12. ORGANIC SEAL USES Products containing only organically produced ingredients may use seal and be labeled �100% organic� Products containing at least 95% organically produced ingredients may use seal and be labeled �organic� Products that contain at least 70% organic ingredients can be labeled �made with organic ingredients� but cannot use USDA seal

14. PESTICIDE RESIDUES FROM ORGANICS ARE LOWER, BUT NOT ZERO Pesticides, typically naturally-occurring, are permitted for use in organics if approved by National Organic Standards Board Some pesticides may inadvertently contaminate organic foods Some �organic� growers may use pesticides not allowed by organic rules

15. Baker, et al, 2002 Organic foods: 127 samples, 23% positive for pesticide residues 10% of positives due to persistent chlorinated hydrocarbon insecticides Remaining 13% showed detectable residues of pesticides not approved for organic use Foods with no market claim: 26,571 samples, 73% positive for pesticide residues

17. WHAT ARE THE RISKS FROM PESTICIDE RESIDUES IN FOODS?

22. NO ADVERSE EFFECTS ARE OBSERVED

24. NUTRITION DIFFERENCES Very little research directly comparing nutritional value of organic vs. conventional foods There is some limited evidence suggesting that organic foods have higher nutrient levels than conventional foods Worthington (2001) analyzed results from 41 comparative studies

25. WORTHINGTON CONCLUSIONS Organic foods had higher levels of vitamin C, iron, calcium, phosphorus, sodium, potassium, magnesium and beta-carotene than conventional foods Nitrate levels were lower in organics relative to conventional foods

26. OTHER REVIEWS Woese, et al (1997) 150 comparative studies between 1926 and 1994 No major differences between organics and conventional, or contradictory findings, with the exception of nitrates, which were lower in organics Bourn and Prescott (2002) Looked at differences from organic vs. conventional fertilizers Study designs and results too variable to provide definitive conclusions

27. INTERESTING STUDY Davis, et al (2004) Compared USDA nutrient content for 43 crops between 1950 and 1999 Statistically reliable declines for protein, calcium, potassium, iron, riboflavin, and ascorbic acid

28. DAVIS CONCLUSIONS Differences primarily due to cultivars (plant varieties) used Selection of cultivars primarily made for resource-using functions such as growth rate, yield, and pest resistance Tradeoffs that limit cultivars� abilities to incorporate soil minerals, transport them within the plant, or synthesize nutrients such as proteins and vitamins

29. SPECIFIC STUDIES Large number of comparative studies reported in the past ten years Frequently look at plant polyphenolics Suggestive that plant polyphenolic levels are increased in organic production

31. REASONS FOR INCREASED PLANT POLYPHENOLICS Use of synthetic fertilizers promotes plant growth at the expense of synthesis of plant secondary metabolites Plant stress due to insect, weeds, or plant pathogens may increase synthesis of plant secondary metabolites; more likely with organics if other pest management tools are not available

33. Naturally-occurring toxins Many chemicals produced by plants themselves show signs of toxicity in animal testing Examples Potatoes � glycoalkaloids Celery � furanocoumarins Many plants � alkaloids May be produced as a means for the plant to defend itself

34. MYCOTOXINS Toxins produced naturally by fungi that live on food plants Examples � aflatoxins, fumonisins Frequently found in crops like corn and nuts that are stored in humid environments Epidemiological correlations between eating mycotoxin-contaminated foods and human cancers Best method of control often is to control insects

35. EFFECT OF PRODUCTION PRACTICES ON LEVELS OF NATURAL TOXINS Very little direct research comparing plant toxins in organic vs. conventional foods Logical that natural toxin levels could be elevated in organics Some evidence suggests mycotoxin levels could be lower in conventional produce

37. MICROBIOLOGICAL RISKS US Estimates - 76 million cases of foodborne illnesses annually, including 320,000 cases of hospitalization and 5,000 deaths Is organic food more or less safe than conventional food in terms of microbiological safety? More manure use in organics, but more stringent regulation of manure in organic agriculture

38. MICROBIOLOGICAL RISKS Mukherjee et al (2004) Compared 476 organic food samples and 129 conventional food samples for various microorganism contamination levels

39. MUKHERJEE FINDINGS (generic E. coli contamination) Conventional produce - 1.6% of samples positive Certified organic produce - 4.3% of samples positive Noncertified �organic� produce - 11.4% of samples positive Statistically, certified organic and conventional had no significant difference; contamination of noncertified organic produce was significantly higher than on conventional or certified organic

40. SUMMARY Organic foods have lower pesticide residue and nitrate levels than convention foods Polyphenolics are higher in organics in some cases Naturally occurring toxins may be higher in organics in some cases There is concern about the microbiological safety of organic produce if it is not handled properly TRADEOFFS!

41. HEALTH SIGNIFICANCE? Differences in chemical/microbiological compositions of foods do not necessarily imply health differences Need to know the magnitude of the differences and whether the magnitude is of significance