Suspicious food items can also be tested. During the months of October and November 2000, there were seven recalls, five of which referred to products contaminated with Listeria monocytogenes . Listeria monocytogenes is ubiquitous in soil and water, but is readily killed by pasteurization. Animals may be silent carriers. The consumption of contaminated milk and meat, particularly unpasteurized or raw products, is often the source of infection.
Animals contaminate vegetables indirectly by the use of manure-based fertilizers.
Post-processing contamination may also occur with improper food handling, particularly with soft cheeses and cold cuts at the deli counter. Animals may be silent carriers. The consumption of contaminated milk and meat, particularly unpasteurized or raw products, is often the source of infection. Animals contaminate vegetables indirectly by the use of manure-based fertilizers. Post-processing contamination may also occur with improper food handling, particularly with soft cheeses and cold cuts at the deli counter.