The aim of this study was to determine the prevalence of Listeria sp. and Listeria monocytogenes in soil samples with reference to type of fertilizers (natural and artificial) and distance from places intensively exploited by men, as well as to determine the relationship between the presence of L. monocytogenes in the soil and in fruits and vegetables. The examined 1,000 soil samples originated from 15 different areas, whilst 140 samples of fruits and 210 samples of vegetables were collected from those areas. L. monocytogenes was isolated only from 5.5 % of all soil samples coming exclusively from meadows intensively grazed by cattle (27.8 %) and areas near food processing plants (25 %) and wild animal forests (24 %). Listeria sp. and L. monocytogenes were not present on artificially fertilized areas and wastelands. L. monocytogenes was detected in 10 % of samples of strawberry, 15 % of potato samples, and 5 % of parsley samples. Our data indicate that Listeria spp. and particularly L. monocytogenes were found in the soil from (1) arable lands fertilized with manure, (2) pasture (the land fertilized with feces of domestic animals), and (3) forests (again, the land fertilized with feces of animals, not domestic but wild). The bacteria were not detected in the soil samples collected at (1) artificially fertilized arable lands and (2) wastelands (the lands that were not fertilized with manure or animal feces). Moreover, a correlation was determined in the presence of L. monocytogenes between soil samples and samples of the examined fruits and vegetables.
Brines after herring marinating pose a serious financial problem to the industry and natural environment. Paradoxically, the brine waste containing biological active compounds like proteases and peptides being responsible for marinade quality is discarded with sewage. Results show that the reuse of brine without filtration is not possible because of increase in the bacterial count and lipid oxidation in marinated herring. The desired parameters of marinades were achieved using brine permeate-50 µm free of the suspension and lipids. The best quality and sensory parameters of marinated herring meat were obtained using permeate-0.22 brine, which not contain microorganisms and lipids, and also a high activity of proteases. Reuse of brine allows reducing by half the losses of protein hydrolysis products (PHP) from meat to brine and for reverse diffusion of PHP and peptidases to meat. The marinades produced with the newly-developed method had up to 25% more PHP, up to 20% lower hardness, 10–20% higher activity of proteases, 40–97% lower indices of lipid oxidation, and 5% higher scores in sensory assessment, compared to the marinades produced with fresh brine. The inexpensive and easy to perform microfiltration of brine affords the possibility of increasing the quality and nutritional value of marinades and minimizing both waste volume and production costs.
Effects of vinegar, oil, and sour cream brines on meat quality of 4 popular cold marinades from herring were investigated in the study. Cover brine type affected the composition and nutritive value of meat as well as the sensory and microbiological quality of marinated herring. Qualitative differences resulted from cover brine penetration into meat, and from diffusion of components from meat to vinegar brine. Compared to oil and sour cream, vinegar brine contributed to increased concentrations of salt and acetic acid, hardness, color brightness of marinades meat and to increased microbial contamination of meat. Furthermore, vinegar caused nitrogen losses to 15%, including valuable products of protein hydrolysis, enzymes, and total volatile bases. The rolling up of fillets reduced diffusion even by 50%. In turn, oil and sour cream were causing mainly a higher fat content and overall sensory evaluation of the marinades.
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