Listeria monocytogenes formadoras de biofilmes em presuntos fatiados e sua sensibilidade aos sanitizantes

Abstract

Listeria monocytogenes is a relevant pathogen in contaminations of foods ready-to-eat, as it is the etiological agent responsible for listeriosis. The objective of this study was to investigate L. monocytogenes in sliced hams and to evaluate the sensitivity to sanitizers. 40 samples of sliced hams were purchased in supermarkets in the city of Recife - PE, nine from large supermarkets and 31 from medium sized supermarkets. In isolation, 25g of each sample was enriched in Fraser Demi Broth and Fraser Broth and seeded in Listeria Selective Agar according to Ottaviani and Agosti. The evaluation of the biofilm formation capacity and the evaluation of the disinfectants on the biofilms of L. monocytogenes in formation and consolidated in vitro was carried out in microdilution plates of polystyrene. Chlorine at 5% concentration and 10% quaternary ammonia were used. The presence of L. monocytogenes in 22.22% (02/09) of the samples collected in large supermarkets in the city and 25.8% (08/31) in medium-sized supermarkets was identified. When submitted to the in vitro biofilm formation test, two isolates were able to form biofilm, both classified as strong formers. In the biofilms in formation, treated with the sanitizers, the two bacteria presented moderate adherence to chlorine and already in relation to the quaternary ammonia the isolate coming from the large supermarket had poor adherence and the one belonging to the medium-sized supermarket had no adhesion. The consolidated biofilms presented a reduction in adhesion to both disinfectants, with a reduction of 75.44% and 79.76% in the idolates of large and medium-sized supermarkets, respectively. The action of quaternary ammonia compared to them represented a decrease of 64.84% and 66.13% of biofilms. The presence of L. monocytogenes, especially of strains capable of forming biofilms, in sliced hams is a relevant factor in single health. A more rigorous inspection is required in establishments regarding the use of adequate sanitizers in the hygiene process, as well as the correct application of them and the constant education of food handlers.