Presence of Listeria at primary production and processing of food of nonanimal origin (FNAO) in Bavaria, Germany

Abstract

Several foodborne outbreaks associated with food of non‐animal origin (FNAO) were reported within the last years. In recent years, Listeria monocytogenes has been associated with such outbreaks. For this reason, different producers of FNAO at the primary production and processing level in Bavaria, Germany, were inspected from July 2020 to June 2021. Environmental and food sampling as well as the sampling of irrigation and processing water was performed to investigate the prevalence of Listeria spp., including L. monocytogenes at facilities that produce ready‐to‐eat FNAO. Altogether, 39 producers of soft fruit, vegetables, ready‐to‐eat raw fruits, and vegetables/fresh cut were inspected. In addition to the on‐spot inspections, 407 samples were taken in total, among them, 229 were swab samples from food contact material and the environment, 59 food samples (including soft fruit, vegetables and ready‐to‐eat vegetables), and 119 samples of irrigation and processing water. Samples were analyzed using methods according to ISO 11290‐1:2017. Furthermore, the samples of irrigation and processing water were also quantitatively tested for the number of Escherichia coli (ISO 9308‐2:2014‐06), enterococci (ISO 7899‐2:2000‐11), and Pseudomonas aeruginosa (ISO 16266:2008‐05). No contamination with E. coli, enterococci, and P. aeruginosa could be detected in most of the samples. Overall, in 12.53% of the samples, Listeria spp. were detected. L. monocytogenes was identified in 1.72% of the environmental and processing water samples, whereas L. monocytogenes was not detected in food samples. In addition to water sources and quality, this study demonstrates that irrigation regime, cultivation, hygienic handling, and maintenance protocols are highly important to reduce the potential contamination of ready‐to-eat soft fruits and vegetables with Listeria spp.