Filth Flies And Cultural Research
Jim Prevor’s Perishable Pundit, September 18, 2008
We wrote a bit about the Fresh Express Fresh Produce Safety Research Conference here, but one of the research presentations — that about filth flies — has occupied many hours of thought as holding the key to food safety.
Oh, it is not the actual research, which is quite preliminary. A hat tip to Michele Jay-Russell, DVM, MPVM, Dipl. ACVPM of the Western Institute for Food Safety and Security, for pointing out to the Pundit that the researchers summarized their report this way:
The high number of filth flies and the species composition on mature lettuce in some Salinas Valley vegetable farms in 2007 were unexpected. Several flies were PCR positive for E. coli O157:H7 and may have been capable of transmission to plants. Our inability to culture E. coli O157 from live flies collected in the same area in 2008 may indicate an ephemeral presence of this pathogen in certain settings. More intriguing questions were generated than answered, prompting us to continue examination of the filth fly E. coli ecological relationship in commercial greens.”
What has consumed us about this particular research is that it was so obvious that there was a problem in the fields. Simple visual observation allowed the researchers to find unusual numbers of flies all over the field. An equally simple technique — sticking some flypaper on small stakes in the field — showed high levels of filth flies.
Now we don’t know that these flies actually constitute a food safety risk — though we also don’t know that they do not.
Maybe that is not the right question though. Even if it won’t lead to E. coli 0157:H7, is there one consumer who would be enthusiastic about eating produce from a field that for some unexplained reason was attracting enormous numbers of filth flies?
After the spinach crisis, we wrote a piece entitled Tale of Two Buyers — the gist of which was that our food safety problem is, at root, a cultural problem caused by the failure of buying organizations to reward buyers who elect to exceed corporate minimums for food safety in procurement.
In other words, if a retailer requires a GAP audit and the buyer can buy GAP-audited product for $10, there is no upside for that buyer to decide that he personally will constrain the supply chain and only consider vendors who are also, say, GlobalGAP-certified and approved to sell to Darden and Tesco. In fact, if he does do this and so pays $12 for the product, he may lose his job or not get the raise, bonus, etc.
When the Leafy Greens Metrics were being articulated, one of our concerns was that our food safety systems depended too much on farmers doing things that they had no direct financial incentive to do and a lot of financial incentive not to do. So, if a farmer sees an animal encroach on a field, that portion of the field is supposed to be marked off as not harvestable — but, of course, then the farmer doesn’t get paid so exactly how likely is this to happen?
It is easy for us to write a speech about a food safety culture in which the end game is that a farmer with flies in the field tells everyone about it so that research can be conducted, and you want the farmer to decline to harvest until both safety is confirmed and product quality isn’t sullied by a disproportionate numbers of flies.
Yet it seems both unrealistic and unfair to simply say that the farmer should be courageous and take a hit for all of us and die some kind of economic Samurai death as he falls on the sword of food safety and product quality.
Supporting a particular culture is about doing real things that make it both likely and possible for people to behave a certain way.
So though scientific research is important, the importance of cultural research should not be overlooked. How do we change things so that the retail buyer has an incentive to exceed his employers’ minimally acceptable food safety standards and pay up for the best product? How do we buy fresh produce so that the farmer, the one on the scene and closest to the crop, has an incentive to say, “I’m suspicious about all these flies, so I’m not selling this crop.”
We have a sense that the answer to our food safety dilemmas may lie in some intersection between a sphere of scientific knowledge and capability and another sphere of cultural reinforcement of personal integrity.