Salmonella from the spice rack!
Continuing with the running series on things that can make you sick when you eat them, Salon.com published a post today detailing how many imported spices are contaminated with Salmonella. The article links back to a New York Times report, describing how FDA officials examined 20,000 shipments of imported spices, finding significant levels of Salmonella contamination in 7% of the samples. Over 10% of samples of coriander, oregano, and basil were contaminated, and high levels of bacteria were also found in curry powder and black pepper. The presence of in these foods should come as no surprise, given the large number of reservoirs that put people at risk for infection. The dried environment on spices will have a bacteriostatic effect on the growth of microorganisms, however drying will not typically kill microorganisms. Fortunately, most of these spices are traditionally used during cooking, and the high heat of cooking will kill introduced bacteria. It is only when seasoning is added after cooking that a significant risk exists.
The report is the result of a 3 year study by the FDA, and recently published in the primary research journal, Food Microbiology. Although the researchers found Salmonella isolates widely distributed geographically between 2007 and 2009, spice preparations from India and Mexico showed the greatest prevalence for being positive for Salmonella. Additionally, several samples were contaminated, even after being treated to reduce the presence of pathogens by a variety of processing methods. Researchers also found that around 7% of the samples positive for Salmonella were contaminated with isolates that were resistant to a variety of first line antimicrobials, including tetracycline, streptomycin, and nalidixic acid.
The report has resulted in some negative and positive responses. The chief of food safety inspections in Mexico maintains that the Mexican food supply remains safe and is checked daily. In contrast, Indian food officials have begun to institute measure to help prevent Salmonella introduction from bird droppings, and also to promote methods to eliminate bacterial contamination during the processing stages.
Outbreaks attributable to contamination of spices have been identified previously. As the NYT article states, outbreaks in 2009 and 2010 of Salmonella sickened hundreds in the majority of states in the country, and one spice processing facility in California was found to be extensively colonized with an infectious isolate of the organism. It is particularly difficult to track outbreaks attributable to contaminated spices, as the long shelf life of these products may mean that an infection may occur months to years after the microorganism entered the food supply. The best recommendations as is generally the case with food-borne illnesses is awareness of of their presence, and to ensure adequate food preparation (washing) and cooking to eliminate potentially pathogenic microorganisms.
Next up on BIO230: Why you shouldn’t wash the chicken prior to cooking!!