Nuts and Grains: Microbiology and Preharvest Contamination Risks

ABSTRACTLow-water-activity foods have been involved in recalls and foodborne disease outbreaks. Increased consumption; better detection methods and reporting systems; improved surveillance, trace-back, and ability to connect sporadic foodborne illnesses; and inadequate implementation of food safety programs are some of the likely reasons for the increase in frequency of recalls and outbreaks linked to dry foods. Nuts and grains can be contaminated with foodborne pathogens at any stage during production, processing, storage, and distribution. Focusing on preharvest contamination, the various potential sources of contamination include soil, animal intrusion, contaminated harvesting equipment, harvest and preharvest handling, storage conditions, and others. The low water activity of nuts and grains prevents the growth of most foodborne pathogens on their surfaces. The long-term survival of bacterial foodborne pathogens (Salmonella,Escherichia coliO157:H7, andListeria monocytogenes) on dry foods has been documented in the literature for different nut types. Preventing contamination is the key to avoiding foodborne disease risks linked to dry foods. The implementation of good agricultur