We would like to propose a valuable research project that would be straightforward and inexpensive to perform and to analyze, and would provide far-reaching useful information for both organic and conventional farmers.
Accusations of microbiological contamination of organic food surfaced this winter, not based on any actual data, but based on incorrect assumptions about manure use on organic farms. It is true that most organic standards prohibit the application of raw manure to crops destined for human food, but few consumers (or biotech/biochemical industry spokespeople) understand the complexity of manure management requirements on organic farms.
Most bacteria commonly found in food are totally harmless. The majority of food borne illness cases are caused by just a few bacterial species, particularly E. coli, salmonella, and listeria. Research done by James Russell at Cornell University in 1998 showed that cows fed hay for only 5 days before slaughter were far less likely to harbor the highly pathogenic E. coli bacteria strain 0157:H7. The apparent reason for this finding is that most conventionally raised cows are fed a grain-based ration which acidifies their digestive tract. Pathogenic strains of E.coli thrive in such an acid environment. The addition of hay to the cow¹s diet not only reduced the acid level of the digestive tract, it also dramatically reduced the number of acid resistant bacteria in the manure.
Since pasture is a requirement for organic dairy and livestock, organically raised animals spend much of their lives eating primarily forage. In the Cornell study, cattle fed primarily hay had only acid-sensitive strains of E.coli that would be readily destroyed in a human stomach. It would therefore be logical to assume that pathogenic acid resistant-bacteria counts would be much lower or non-existent in the manure of organically raised animals.
An interesting followup to this Cornell study would involve testing manure samples for E. coli 0157:H7 from a large number of cows raised under 4 main conditions:
1. Large scale conventional feed lot and confinement dairy operations (CAFO operations)
2. Smaller scale conventional family dairy and beef farms using pasture
3. Small scale organic dairy and beef farms using pasture
4. Large scale confinement organic dairy farms (we believe there is one in Colorado and another in Maryland)
A project such as this would far more effective than looking downstream at the microbiological contamination on fruits and vegetables, partly because of the high potential for contamination after the produce is harvested. This project would look upstream to the source of the contamination, and could help farmers develop management approaches that would prevent contamination from occurring.
We personally do not have the means to do such a research project, however are there any researchers or grant money out there that would be interested in picking up on this idea? We hope so, for this could be extremely valuable information to improve good organic management, for certifiers and the USDA to better develop effective organic standards, for agricultural consultants/advisors to development improved management criteria, and for the media and consumers to better understand the real risks of E coli 0157:H7. If the results come out as the Cornell research would predict, this could also be a useful marketing tool for organic producers.
Mary-Howell and Klaas Martens
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