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Listeria monocytogenes is a foodborne pathogen of concern in dairy processing facilities, with the potential to cause human illness and trigger regulatory actions if found in the product. Monitoring for Listeria spp. through environmental sampling is recommended to prevent establishment of these microorganisms in dairy processing environments, thereby reducing the risk of product contamination. To inform on L. monocytogenes diversity and transmission, we analyzed genome sequences of L. monocytogenes strains (n = 88) obtained through the British Columbia Dairy Inspection Program. Strains were recovered from five different dairy processing facilities over a 10 year period (2007-2017). Analysis of whole genome sequences (WGS) grouped the isolates into nine sequence types and 11 cgMLST types (CT). The majority of isolates (93%) belonged to lineage II. Within each CT, single nucleotide polymorphism (SNP) differences ranged from 0 to 237 between isolates. A highly similar (0-16 SNPs) cluster of over 60 isolates, collected over 9 years within one facility (#71), was identified suggesting a possible persistent population. Analyses of genome content revealed a low frequency of genes associated with stress tolerance, with the exception of widely disseminated cadmium resistance genes cadA1 and cadA2. The distribution of virulence genes and mutations within internalin genes varied across the isolates and facilities. Further studies are needed to elucidate their phenotypic effect on pathogenicity and stress response. These findings demonstrate the diversity of L. monocytogenes isolates across dairy facilities in the same region. Findings also showed the utility of using WGS to discern potential persistence events within a single facility over time. [ABSTRACT FROM AUTHOR]

Inspections of fresh produce operations for compliance with the Produce Safety Rule (PSR) have identified cleaning and sanitizing (C/S) as a significant challenge. To better understand C/S practices in the produce industry a national survey was administered over a 3-week period in summer 2020 to fresh produce operations in U.S. Survey responses (n = 162) represented 135 produce operations from 18 different states. The most common materials reported for harvesting containers (n = 50 responses) were plastic (80%), wood (30%), cardboard (16%), and canvas (12%), while stainless steel (81%) and plastic (71%) were most commonly used for post-harvest equipment (n = 42 responses). Bleach (40/63), quaternary ammonium compounds (32/63), and peracetic acid (26/63) were the most commonly reported sanitizers. Respondents indicated there is a need for resources on principles and practical implementation of C/S, identification of hazards and prioritizing C/S activities, establishing a C/S program, and verification of C/S effectiveness, in English, Spanish and other languages. High turnover and seasonal workforce (37/65) and no time to C/S (19/65) were indicated as major barriers for improving C/S in a facility. The results of the survey helped guide a virtual C/S workshop in 2021, and an in-person workshop currently in development. [ABSTRACT FROM AUTHOR]

The Produce Safety Alliance (PSA) created the first standardized and U.S. Food and Drug Administration-recognized Grower Training curriculum focused on the Produce Safety Rule. The standard PSA Grower Training is an 8-h, lecture-based training with limited opportunities for participant engagement. The objectives of this study were to increase PSA Grower Training participant engagement and assess immediate knowledge gain. We developed and incorporated supplemental learning activities into the existing training curriculum (PSA+). The two objectives were assessed using pre- and posttraining tests and evaluation comments, respectively, from 12 trainings (2019 to 2020; 6 PSA and 6 PSA+). Participant knowledge gain was significant (t = -16.72, P < 0.01) for each training and comparable between formats. Three questions with identical training content between PSA and PSA+ had significantly higher posttraining scores in PSA+. A question on what should guide risk management actions had less participants choosing the intended correct answer between pre- and posttest. Participants reported improved engagement in PSA+ and highlighted the need for more diversity and cultural sensitivity in PSA slides and verbal delivery of information. These findings identified additional resources that would be useful to participants and helped inform future training and trainer improvements. [ABSTRACT FROM AUTHOR]