Large, renowned outbreaks associated with low-moisture foods (LMFs) bring to light some of the potential, inherent risks that accompany foods with long shelf lives if pathogen contamination occurs. Subsequently, in 2013, Beuchat et al. (2013) noted the increased concern regarding these foods, specifically noting examples of persistence and resistance of pathogens in low-water activity foods (LWAFs), prevalence of pathogens in LWAF processing environments, and sources of and preventive measures for contamination of LWAFs. For the last decade, the body of knowledge related to LMF safety has exponentially expanded. This growing field and interest in LMF safety have led researchers to delve into survival and persistence studies, revealing that some foodborne pathogens can survive in LWAFs for months to years. Research has also uncovered many complications of working with foodborne pathogens in desiccated states, such as inoculation methods and molecular mechanisms that can impact pathogen survival and persistence. Moreover, outbreaks, recalls, and developments in LMF safety research have created a cascading feedback loop of pushing the field forward, which has also led to increased attention on how industry can improve LMF safety and raise safety standards. Scientists across academia, government agencies, and industry have partnered to develop and evaluate innovate thermal and nonthermal technologies to use on LMFs, which are described in the presented review. The objective of this review was to describe aspects of the extensive progress made by researchers and industry members in LMF safety, including lessons-learned about outbreaks and recalls, expansion of knowledge base about pathogens that contaminate LMFs, and mitigation strategies currently employed or in development to reduce food safety risks associated with LMFs.

Sous-videcooking is a growing trend among retailers and consumers. Foodborne pathogens may survive the cooking if nonvalidated parameters are used or if pathogens have enhanced thermalresistance. Pathogen inactivation from sous-vide cooking was determined when introduced directly to beef products or via contaminated spices, and with or without a finishing step. Beef products (ground beef, tenderized, and nontenderized steaks) were inoculated with pathogens (Salmonella Montevideo and Escherichia coli O157:NM) in three ways: 1) directly onto the meat 2) ground black pepper incorporated into the recipe 3) ground pepper equilibrated at 30% RH (4 d) prior to incorporation. Beef samples were vacuum-packaged and submerged in a 62.5°C water bath for 120 min. Samples were sampled at 5, 10, 20, and 120 min (recommended from a partner quality study), and a duplicate was grilled to a specific internal temperature (74°C for ground beef, 57°C for steaks) and sampled. Sous-vide cooking reduced pathogen populations by >5 log CFU/g after most treatment times, but less than grilled counterparts (ca. 1-2 log CFU/g difference; p < 0.05).There were no statistically significant differences between inoculation methods, but the tenderization of steaks resulted in significantly lower reductions of pathogens from sous-vide cooking (p < 0.05). Thisresearch challenged sous-vide cooking parameters (120 min, 62.5°C). It showed sous-vide alone lowered pathogens by >4 log CFU/g after most 20-min treatments, but 120-min sous-vide treatments or grilling would be needed for >5-log reductions.Contaminated pepper led to less consistent reductions during the cooking process, yet 2-h sous-vide still achieved a 5-log reduction. Sous-vide cooking instructions must be validated as more products and recipes are marketed.

Summary: This study demonstrates the importance of water activity in predicting milk powder characteristics. Moisture content is easier to measure but is limited in overall application. The combination of the 2 measurements through moisture sorption isotherms offers useful insights. Using the dynamic dewpoint isotherm (DDI) method, moisture adsorption and desorption isotherms for nonfat dry milk (NFDM) and milk protein concentrate (MPC-85) at different temperatures were examined. The NFDM showed sigmoidal (type II) adsorption isotherms, whereas NFDM desorption and MPC-85 isotherms displayed J-shaped (type III) isotherms. Temperature significantly impacted isotherms, and hysteresis was more pronounced in MPC-85. Models like Oswin and Chung-Pfost effectively described these moisture interactions and could be used for predictive estimations of shelf life and other quality changes. The findings demonstrate how composition and temperature influence the quality of milk powders, aiding manufacturers in handling, processing, and storage.

Pathogen contamination and harborage in low-moisture food (LMF) processing environments have resulted in outbreaks and recalls, but researchers are limited in their abilities to investigate solutions. Methods used in most laboratory studies do not accurately reflect the route of contamination or harborage of pathogens in LMF environments, which complicates studying of sanitation methods. Inoculation methods were compared to establish low-moisture food persistent bacterial populations (LMF PBPs) that realistically reflect populations found in LMF environments. Culture-preparation techniques, food matrices, and ratios of nutrient to moisture were compared for their impacts on Salmonella Tennessee survival. A slurry method with 0.5 mL of culture to 0.4 g (NFDM) was easiest to form, inoculate, and process for further investigation, as was more consistent than other methods. With the chosen technique, LMF PBPs of Salmonella Tennessee (0.5: 0.4 [mL Salmonella Tennessee to g Powder]) with different powders (NFDM, peanut butter powder [PB], chicken powder [CP] and silicon dioxide [SiO₂]) were made using lawn-based and broth-based cultures and distributed evenly on sterilized stainless-steel coupons to compare the impacts of preparation and food matrix on survival. Coupons stored at 22-25°C and 50% relative humidity (RH) were assessed on 0, 1, 3, 5, and 7 days. Matrices and culture preparation showed significant differences (p≤ 0.05). Salmonella LMF PBP derived from bacterial lawns demonstrated higher initial populations (10.1 ± 0.0 log CFU/cm²) compared to the broth cultures (8.2 ± 0.2 log CFU/cm²). Salmonella LMF PBP reductions were lower for the lawn-prepared cultures (0.3-2.7 log CFU/cm²) compared to broth-based cultures (1.0-5.1 log CFU/cm²) for all food matrices. Salmonella in LMF PBP with SiO₂ (2.7-5.1 log CFU/cm²) reduced significantly more than in other food matrices (0.7-2.2 log CFU/cm²) and Sal without a matrix (0.3-1.5 log CFU/cm²) for both culturing methods.