Design Elements of Listeria Environmental Monitoring Programs in Food Processing Facilities: A Scoping Review of Research and Guidance Materials

Abstract

Occurrence of Listeria monocytogenes (Lm), the causative agent of listeriosis, in food processing facilities presents considerable challenges to food producers and food safety authorities. Design of an effective, risk-based environmental monitoring (EM) program is essential for finding and eliminating Lm from the processing environment to prevent product contamination. A scoping review was conducted to collate and synthesize available research and guidance materials on Listeria EM in food processing facilities. An exhaustive search was performed to identify all available research, industry and regulatory documents, and search results were screened for relevance based on eligibility criteria. After screening, 198 references were subjected to an in-depth review and categorized according to objectives for conducting Listeria sampling in food processing facilities and food sector. Mapping of the literature revealed research and guidance gaps by food sector, as fresh produce was the focus in only 10 references, compared to 72 on meat, 52 on fish and seafood, and 50 on dairy. Review of reported practices and guidance highlighted key design elements of EM, including the number, location, timing and frequency of sampling, as well as methods of detection and confirmation, and record-keeping. While utilization of molecular subtyping methods is a trend that will continue to advance understanding of Listeria contamination risks, improved study design and reporting standards by researchers will be essential to assist the food industry optimize their EM design and decision-making. The comprehensive collection of documents identified and synthesized in this review aids continued efforts to minimize the risk of Lm contaminated foods.

Listeria monocytogenes environmental sampling program in ready‐to‐eat processing facilities: A practical approach

“…The EMP consists of the collection of samples from food contact and nonfood contact surfaces of a food processing facility to detect Listeria contamination and verify the adequacy of control measures (Zoellner et al., 2018). As such, an EMP should be validated to assess its efficacy.…”

“…As a general rule, regulatory agencies guide the design of an EMP on a risk‐based approach using factors such as the ability of the RTE food to support the growth of L. monocytogenes , the methods used to control postlethality step contamination, the likelihood of contamination, and the risk of being linked to human listeriosis (Zoellner, Ceres, Ghezzi‐Kopel, Wiedmann, & Ivanek, 2018). However, many international food safety authorities have different approaches with regard to EMPs for Listeria spp.…”

“…A wide variety of documents have been published to provide the food industry with recommendations for designing an effective Listeria EMP. These include regulatory documents (policy or compliance documents issued by the food safety authority such as a Government agency or body) and guidance documents (not mandatory instructions that provide practical expectations or compliance recommendations issued by Government agencies and supply chain or buyer agencies), all aimed at supporting the FBO and competent authorities to comply with regulatory requirements (Murugesan, Kucerova, Knabel, & LaBorde, 2015; Zoellner et al., 2018). Overall, the abovementioned documents cover all aspects of a Listeria EMP: sampling location, time of sampling, frequency and number of sampling, sampling procedure, method of analysis, data reporting and interpretation, corrective action, and food disposition.…”

Detection and Prevalence of Listeria in U.S. Produce Packinghouses and Fresh-Cut Facilities

“…Therefore, the validation sampling results demonstrate the importance of sampling by an outside party, which can increase confidence in results and also identify potentially problematic sampling schemes. It can also serve to periodically validate the efficacy of a routine Listeria environmental monitoring program (1,28). However, a single validation sampling may not necessarily be appropriate to assess routine sampling conducted over a preceding year; discrepancies between routine and validation sampling should be followed up by a more comprehensive sampling process review and, if deemed appropriate, a root cause analysis investigation (e.g., of the routine sampling procedures if the validation sampling provides considerably larger proportion of positive samples).…”

“…However, there is still a lack of research to support these guidance documents, as compared with other food sectors. A 2018 scoping review of research and guidance materials related to Listeria PEM programs revealed that, of 74 references relating to environmental monitoring, only four were related to the fresh produce sector, compared with 20 and 19 in the meat and dairy sectors, respectively (28).…”