Why? Despite progress improving the quality and safety of foods, the CAST report explains, any raw agricultural product can be contaminated. Bacteria may survive despite aggressive controls at the processing level, or the food may become contaminated somewhere along the way during transport, preparation, cooking, serving, and storage.

Further, the CAST report stresses what food safety and public health officials have all recognized: Everyone in the food system, from producers to preparers, must be vigilant in controlling microbiological hazards.  The following factors make controlling foodborne pathogens particularly challenging:

• Emerging pathogens demand even greater food safety vigilance than what was required in previous generations because as pathogens are evolving and becoming more widespread, bacteria are becoming more resistant to treatments.
• The food supply has become global, with many different countries supplying food products to the United States.
• More food is prepared and consumed away from home. The U.S. Department of Agriculture (USDA) estimates that consumers spend 48 cents of every food dollar eating out. Also, an increasing amount of food prepared away from the home is then taken home for consumption, thus creating more opportunities for contamination.
• Consumers may not always be consistent with handwashing and safe thawing habits.

Adding to the challenge, microorganisms continue to adapt and evolve, often increasing their degree of virulence. For example, E. coli O157:H7 was first identified in 1982, but the bacterium has already been indicated as a cause for severe vomiting, bloody diarrhea, and even hemolytic uremic syndrome, which leads to kidney failure (CDC).

Foodborne pathogens emerge for many reasons including: the globalization of our food supply; introduction of pathogens in different geographic areas as in the case of Vibrio cholerae introduced in the southern U.S. by ballast water; international travelers are often introduced to foodborne pathogens that are uncommon in the U.S.; and changes in microorganisms leading to antibiotic resistance and ability to thrive in different environmental conditions (WHO, 2002).

At the same time, bacteria already recognized as sources of foodborne illness have found new modes of transmission. While many illnesses from E. coli O157:H7 occur from eating undercooked ground beef, the bacterium has also been traced to other foods, including salami, raw milk, lettuce, and unpasteurized apple cider.