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

Simone Wartha; Stefanie Huber; Iris Kraemer; Thomas Alter; Ute Messelhäußer

doi:10.1016/j.jfp.2022.11.007

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

J Food Prot. 2023 Jan;86(1):100015. doi: 10.1016/j.jfp.2022.11.007. Epub 2022 Dec 16.

Authors

Simone Wartha¹, Stefanie Huber², Iris Kraemer², Thomas Alter³, Ute Messelhäußer²

Affiliations

¹ Bavarian Health and Food Safety Authority, Department Erlangen and Oberschleißheim, Veterinärstraße 2, 85764 Oberschleißheim, Germany. Electronic address: Simone.Wartha@lgl.bayern.de.
² Bavarian Health and Food Safety Authority, Department Erlangen and Oberschleißheim, Veterinärstraße 2, 85764 Oberschleißheim, Germany.
³ Institute of Food Safety and Food Hygiene, Freie Universitaet Berlin, Berlin, Germany.

PMID: 36916596
DOI: 10.1016/j.jfp.2022.11.007

Abstract

Several foodborne outbreaks associated with food of non-animal origin (FNAO) were reported within the last years. In recent years, Listeriamonocytogenes 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 Listeriaspp., 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 ISO11290-1:2017. Furthermore, the samples of irrigation and processing water were also quantitatively tested for the number of Escherichiacoli (ISO9308-2:2014-06), enterococci (ISO7899-2:2000-11), and Pseudomonasaeruginosa (ISO16266:2008-05). No contamination with E.coli, enterococci, and P.aeruginosa could be detected in most of the samples. Overall, in 12.53% of the samples, Listeriaspp. 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 Listeriaspp.

Keywords: FNAO; Irrigation system; Listeria; Processing facilities; Soft fruit; Vegetables.

MeSH terms

Escherichia coli
Food Contamination / analysis
Food Microbiology
Fruit
Listeria monocytogenes*
Listeria*
Vegetables