Anytime there is a massive outbreak involving produce, those of us tasked with produce safety should be asking the difficult questions about our prevention methods and why they failed.
There are emerging trends apparent with pathogens in produce: a trend away from Salmonella and E. coli and toward more novel pathogens such as Listeria monocytogenes and Cyclospora cayetanesis. The reduction in E. coli and Salmonella outbreaks involving produce may be attributed to better controls at the packing and processor level, but most of the recent contamination issues have a direct link to the farm. There is also a trend apparent with the vehicles for produce-borne infection.
We have not seen a large-scale tomato-borne outbreak in quite a while. The success with tomatoes in particular is a good example of a successful industry-led intervention. Major achievements have been made by the industry, especially in Florida where Tomato-GAP requirements are in place and enforced. Fresh-cut bagged salad items (with the exception of the problematic cilantro) are indicated less as vehicles, and, in spite of the problems with cantaloupe and Listeria, Salmonella outbreaks involving this commodity show a decline.
Cyclospora and Listeria have come to the fore as pathogens as a result of their unique abilities to survive the typical steps that show promise in controlling other produce-borne infectious agents. Once Listeria adheres to a surface and colonizes it, this bacterium is capable of withstanding almost any treatment with surface sanitizers. Other factors increasing virulence include the ability to multiply at temperatures that would otherwise halt the propagation of harmful mesophilic bacteria and a relatively low infectious dose (in the immune-compromised, around 500).
Cyclospora is a protozoan parasite that forms an oocyst. These hardy survival forms of this parasite allow it to remain infective for an extended period of time and protect it from treatments with sanitizers. The current outbreak in imported cilantro supplied by Mexico’s Pueblo region could not have been prevented anywhere else than on the farm. FDA reports that operations in this region of Mexico lack safe water supplies and have grossly inadequate sanitary facilities. Undoubtedly, these areas have had third-party oversight. We don’t have a clear picture of what types of controls were in place and why they failed, but it again raises some very serious questions about the competency and capacity of our current supplier control and food safety auditing efforts.
While progress has been made in the facilities that handle produce, more needs to be done at the farm level. Growers are faced with formidable challenges when implementing GAP programs. Farms are non-sterile environments subject to all sorts of foodborne illness hazards, mainly from animals, domestic and wild, contaminated irrigation sources, and, as recently revealed in the FDA investigation of the current Cyclospora outbreak, chronically poor or non-existent hygienic standards.
Policing vast expanses of crops is quite challenging. It is very easy to lose control over harvesting operations when hundreds of workers are spread out over large territories. In addition to the logistical problem of locating and maintaining sanitary portable hygiene facilities in these remote areas, farmers must cope with poorly educated workers, language barriers and cultural issues. However, there can be no tolerance for fecal matter in a human food crop.
Once again we see operations that are failing to provide the most basic of all sanitation practices. We may never know all of the facts surrounding the current Cyclospora problem, but after all the industry has done to improve sanitation, it is disheartening and frustrating to all of us trying to make a difference to see a complete breakdown of basic sanitation in a major foreign supplier. It is also pathetic that buyers in the U.S. would purchase products grown under these conditions. The people responsible need to provide some answers, but, as history has shown, the produce industry does not have all the answers.
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