Utilizing whole-genome sequencing to characterize Listeria spp. persistence and transmission patterns in a farmstead dairy processing facility and its associated farm environment.

Farmstead dairy processing facilities may be particularly susceptible to Listeria spp. contamination due to the close physical proximity of their processing environments (PE) to associated dairy farm environments (FE). In this case study, we supported the implementation of interventions focused on improving (1) cleaning and sanitation efficacy, (2) hygienic zoning, and (3) sanitary equipment and facility design and maintenance in a farmstead dairy processing facility, and evaluated their effect on Listeria spp.

Intensive Environmental Sampling and Whole Genome Sequence-based Characterization of Listeria in Small- and Medium-sized Dairy Facilities Reveal Opportunities for Simplified and Size-appropriate Environmental Monitoring Strategies.

Small- and medium-sized dairy processing facilities (SMDFs) may face unique challenges with respect to controlling Listeria in their processing environments, e.g., due to limited resources.

Gram-negative postpasteurization contamination patterns of single-serve fluid milk produced in 4 different processing facilities.

An analysis of historic data on high temperature, short time (HTST) fluid milk quality showed higher total bacterial counts and lower sensory defect judging scores at d 14 postprocessing for milk packaged in single-serve containers as compared with milk packaged in half-gallon containers from the same processing facilities. As postpasteurization contamination with gram-negative bacteria is likely a major contributor to an increased spoilage risk associated with milk packaged in single-serve containers, we performed a comprehensive assessment of the microbial quality and shelf life of 265 commingled single-serve HTST fluid milk samples (including white [unflavored] skim, white [unflavored] 1%, chocolate skim, and chocolate 1%) collected over 2 visits to 4 commercial fluid milk processing facilities. Over 2 initial sampling visits, the frequency of gram-negative spoilage ranged from 14 to 79% of the product collected from the 4 facilities, with significant differences of gram-negative spoilage frequency between sampling visits, facilities (sampling visit 1, sampling visit 2, and both sampling visits combined), milk types (sampling visit 2), and filler lanes (sampling visit 2).

Microbacterium represents an emerging microorganism of concern in microfiltered extended shelf-life milk products.

Growing interest in the manufacture of extended shelf-life (ESL) milk, which is typically achieved by a high-temperature treatment called ultra-pasteurization (UP), is driven by distribution challenges, efforts to reduce food waste, and more. Even though high-temperature, short-time (HTST) pasteurized milk has a substantially shorter shelf life than UP milk, HTST milk is preferred in the United States because consumers tend to perceive UP milk as less desirable due to the "cooked" flavor associated with high-temperature processing. While ESL beyond 21 d may be possible for HTST, the survival and outgrowth of psychrotolerant aerobic spore-forming bacteria can still be a limitation to extending shelf life of HTST milk.

Development and deployment of a supply-chain digital tool to predict fluid-milk spoilage due to psychrotolerant sporeformers.

Psychrotolerant sporeformers pose a challenge to maintaining fluid milk quality. Dynamic temperature changes along the supply chain can favor the germination and growth of these bacteria and lead to fluid milk spoilage. In this study, we aim to expand on our previous work on predicting milk spoilage due to psychrotolerant sporeformers.