Food and feed can be a source of pathogenic and opportunistic pathogenic bacteria that can subsequently colonize the host's digestive tract and cause health complications. The way of storing and processing food and feed has a significant impact on the frequency of these bacteria, but also on the production of their toxins and the ability to virulence. One of the objectives of microbiological analysis is to monitor the occurrence and activity of opportunistic pathogens such as Sarcina ventriculi and Sarcina maxima, Lactococcus garviae and Streptococcus agalactiae in the host microbiota, food and feed, at different stages of processing. The genotypic and phenotypic analyzes performed will help to clarify their pathogenicity and interaction with other microorganisms and the host itself.
Furthermore, the occurrence of pathogenic sporulating bacteria in foodstuffs of plant and animal origin is studied. In particular, these are bacteria of the Bacillus cereus and Clostridium perfringens groups. The susceptibility of these species and Listeria monocytogenes to the bacteriocin-producing Bacillus sp. PT89 is also tested. The conditions under which bacteriocin PT89 is expressed and its properties are also studied: effect on tissue cultures, haemolytic and lecithinase activity, resistance to digestive enzymes, various pH values, bile salts, temperatures, etc. Moreover, the effect of PT89 on Listeria monocytogenes survival and growth will be tested in silage. Silage will be experimentally inoculated with this bacterium and its counts will be monitored with and without addition.
Distribution of genes encoding virulence factors in Aeromonas spp., Isolated from breeding ponds, drinking water sources, and recreational areas is studied. The risk of breeding fish disease, fish product contamination and human food infections will be evaluated.
We carry out the determination of inhibitory activity (MIC) of plant extracts against pathogenic bacteria, such as salmonella, campylobacter, streptococci, staphylococci, etc. Further, interactions of the above-mentioned substances (antagonism, synergy, additive effect) with antibiotics by FIC determination are monitored.
Effects of microwave treatment on mould growth inhibition are tested on plant materials contaminated with moulds. The activity of alternarious mycotoxins on in vitro cell lines will be studied, their cytotoxicity and effect on lactobacilli adhesion will be studied. It will be tested whether probiotic bacteria are able to balance or otherwise interact with mycotoxins in order to use them as a protective culture to reduce mycotoxin content in food.
