Outbreaks are, however, only the most visible aspect of a much broader, more persistent problem, as there are large numbers of sporadic cases and smaller outbreaks that are not reported, even in the U.S. where an excellent surveillance system is in place.
• The continual evolution of consumer eating patterns, including a preference for fresh and minimally processed ready-to-eat foods, and new types of prepared convenience products being marketed and consumed.
• Changing farm practices, particularly related to the disposal of manure from large-scale animal production facilities, which have an indirect impact on food contamination. Uncomposted or untreated manure frequently contains pathogens that can contaminate nearby agricultural operations via water, wind or direct contact. This issue is exacerbated by progressive urbanization that is occurring in developed countries, including the U.S., resulting in increasing proximity of crops to animal husbandry operations and the potential for cross-contamination.
• Inadequate or improper refrigeration during the "field to the fork" continuum in which a single break in the cold chain can create conditions under which any existing bacterial pathogens may flourish. The potential links in the cold chain include raw material harvesting and distribution, manufacturing plant packaging and storage conditions, loading docks, trucks, distribution depots, retail and foodservice holding coolers, store merchandisers, transportation by the consumer between the store and home and home refrigerators.
• An aging population that is more susceptible to foodborne illness.