Studies point to deficiencies in food safety in leafy greens
Foodborne illnesses resulting from leafy green products have increased more than consumption over the past 35 years, according to the Centers for Disease Control and Prevention (CDC).
Consumption of leafy greens has increased over the years, but it does not completely explain the increase in the proportion of foodborne outbreaks due to leafy green consumption, said Michael Lynch, a CDC researcher who presented his research findings at the International Conference on Emerging Infectious Diseases in Atlanta, in March.
Lynch and others from CDC looked at more than 10,000 foodborne illness reports from 1973 to 2006. During that time, 5 percent of illnesses were attributed to leafy greens, with 60 percent of those cases caused by norovirus, 10 percent by salmonella and 5 percent by E. coli. However, the per capita data showed the rate of foodborne illness was increasing more than the rate of consumption.
During the 1986-1995 period U.S. leafy green consumption increased 17 percent from the previous decade. During the same period, the proportion of all foodborne disease outbreaks due to leafy greens increased 60 percent. Likewise during 1996-2005 leafy green consumption increased 9 percent and leafy green-associated outbreaks increased 39 percent, Lynch said in a statement.
While the study did not look at the factors that caused the contamination in the first place, the widespread distribution of related illnesses points to contamination in the processing facility or the field.
The proportion of outbreaks due to leafy greens has increased beyond what can be explained by increased consumption. Contamination can occur anywhere along the chain from the farm to the table. Efforts by local, state and federal agencies to control leafy green outbreaks should span from the point of harvest to the point of preparation, Lynch said.
A second study also released in March looked at the FDA plant inspection process of spinach and leafy greens processors.
The report by the U.S. House of Representatives Oversight Committee claims FDA did a poor job of inspecting spinach processing facilities. The report, FDA and Fresh Spinach Safety, is an investigation into the September 2006 outbreak of E. coli in bagged spinach. Representatives Henry Waxman (D-Calif.) and Rosa DeLauro (D-Conn.) requested the study, which looked at all spinach inspection reports from 2001 through 2007.
Over the seven year period, 67 fresh-cut spinach facilities were inspected 199 times, which works out to one inspection per plant every 2.4 years. FDAs stated goal is to inspect high-risk facilities once every year. According to the research, a number of plants were inspected annually, which means some facilities had fewer than one inspection every 2.4 years.
Of those 199 inspection reports, 47 percent reported objectionable conditions at the processing facility, most often related to plant and worker sanitation and plant construction. More than half of the objectionable conditions noted were for facility sanitation, including unclean restrooms and an accumulation of litter, according to the report.
One inspection of a California plant noted salad residue on equipment as well as an unidentified scrapable brown residue on at least four chutes and two conveyor lines. That inspector also found a tear in a conveyor belt, rust and condensation on exposed beams over the processing line and loose and cracked ceiling tiles over the production area.
FDA did not follow up with any of the reports of objectionable conditions with its enforcement powers. The agency referred only one case to the state for follow-up actions. The report also states that FDA overlooked repeat violations in 38 of the inspection reports, instead requesting voluntary compliance for the same violations.
The oversight committees report noted one Arizona processing facility that had been inspected five times between 2001 and 2006 and was cited for the same violations repeatedly, but FDA took no enforcement action. Those violations included ineffective measures to prevent foreign materials from getting into the food, failing to clean and maintain processing equipment, failure to prevent condensation from getting into products and failure to maintain plant sanitation records.
The report criticizes FDA for not conducting microbial testing, even when a problem was known to exist. One-fifth of the FDA inspection reports included laboratory testing, but only three referenced the tests in follow-up inspections. One California processing facility reported to a listeria finding in a drain swab test to an FDA inspector, but no other tests by the plant staff came back positive. The inspector did not take samples at that inspection, or at the next inspection. It wasnt until more than a year after the plant reported the finding finding that FDA inspectors swabbed the facility, and the test came back positive for a more dangerous form of listeria that can cause meningitis, the report states.
Leafy greens growers and handlers took the first step last year to self-regulate the industry, which was seen as a necessity before regulators without knowledge of the industry began passing laws. The resulting Leafy Greens Marketing Agreement (LGMA) preemptively addressed many of the issues in the oversight committees report and provides clear, scientific measures for leafy greens processors. LGMAs first audit report indicates that the level of compliance is high and processors are spending more time and money on ensuring food safety.