The burden of foodborne illness and the number of food recalls associated with microbial hazard contamination of low water activity foods (LA_wF) has been on the rise in recent years.  These foods are naturally low in moisture or are produced from higher moisture foods through dehydration and other processes. LA_wF are generally perceived as safe by consumers, and many LAwF are consumed as ready-to-eat products with no consumer-level pathogen reduction step such as cooking.  While LAwF are susceptible to contamination from a wide range of microbial hazards, Salmonella has emerged as the pathogen of concern in many of these products, and most control efforts have been directed at this pathogen.  Other relevant microbiological hazards of concern may include: Cronobacter sakazaki; Listeria monocytogenes; shiga toxin producing Escherichia coli; Pseudomonas spp.; the spore formers Clostridium perfringens; Staphylococcus aureus; and Bacillus cereus; and toxigenic molds. Although pathogens cannot grow in LA_wF due to the low A_w, many pathogens can survive and remain viable for extended periods.  Pathogen populations may increases after reconstitution and/or during preparation of food products prior to consumption.  Traditionally effective processing interventions achieving >5 log reduction used for high moisture level foods, are generally not as efficacious when applied to LAwF.  The combination of low A_w with the high solute and/or fat content may contribute to enhanced survival and thermal resistance of pathogens in these foods.  The most important control measures for LA_wF involve preventing cross-contamination, good manufacturing practices, and hazard analysis critical control point (HACCP) programs that vary depending on the microbiological hazard and LAwF. Audits and microbial monitoring of LAwF products and food processing environments are also important strategies for industry to monitor food safety and will vary based on microbiological hazards.

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