Genetic Diversity and Potential Virulence of Listeria monocytogenes Isolates Originating from Polish Artisanal Cheeses.

Artisanal cheeses can be sources of Listeria monocytogenes and cause disease in humans. This bacterial pathogen is a species of diverse genotypic and phenotypic characteristics. The aim of the study was to characterize 32 isolates of L. monocytogenes isolated in 2014-2018 from artisanal cheeses. The isolates were characterized using whole genome sequencing and bioinformatics analysis. The artisanal cheese isolates resolved to four molecular groups: 46.9% of them to IIa (1/2a-3a), 31.2% to IVb (4ab-4b-4d-4e), 12.5% to IIc (1/2c-3c), and 9.4% to IIb (1/2b-3b-7). Two evolutionary lineages emerged: lineage II having 59.4% of the isolates and lineage I having 40.6%. The sequence types (ST) totaled 18: ST6 (15.6% of the isolates), ST2, ST20, ST26, and ST199 (each 9.4%), ST7 and ST9 (each 6.3%), and ST1, ST3, ST8, ST16, ST87, ST91, ST121, ST122, ST195, ST217, and ST580 (each 3.1%). There were 15 detected clonal complexes (CC): CC6 (15.6% of isolates), CC9 (12.5%), CC2, CC20, CC26, and CC199 (each 9.4%), CC7 and CC8 (each 6.3%), and CC1, CC3, CC14, CC87, CC121, CC195, and CC217 (each 3.1%). The isolates were varied in their virulence genes and the differences concerned: inl, actA, LIPI-3, ami, gtcA, aut, vip, and lntA.

Insight into Trichinella britovi Infection in Pigs: Effect of Various Infectious Doses on Larvae Density and Spatial Larvae Distribution in Carcasses and Comparison of the Detection of Anti-T. britovi IgG of Three Different Commercial ELISA Tests and Immunoblot Assay.

There is limited information available on the Trichinella britovi (T. britovi) muscle larvae (ML) distribution in pig muscle and the humoral immune response of pigs infected with moderate doses of this parasite; therefore, this study investigated the infectivity of a Polish strain of T. britovi for pigs, the antibody response of this host to various doses of T. britovi, and the efficiency of three different commercial ELISA kits and an immunoblot assay at detecting anti-T. britovi IgG. No significant differences in terms of the infection level of particular muscles or of whole carcasses between pigs infected with 3000 and those infected with 5000 ML of T. britovi were observed. The highest intensity of T. britovi infection was reported in the diaphragm pillars. The larvae of T. britovi showed homogeneous distribution with respect to the muscle side. Statistically, specific IgG antibodies against excretory-secretory (ES) antigens of Trichinella ML were first detected by all ELISA protocols on day 36 post infection; however, individual pig results showed some differences between the three tests applied. A significant increase in the level of anti-T. britovi IgG was observed between days 36 and 41 post infection, and from day 45 until day 62 after T. britovi infection, production of these antibodies reached its plateau phase. No positive correlation was found between the anti-T. britovi IgG level and the larvae density in 15 different muscles. Sera of T. britovi-infected pigs showed reactivity with T. britovi ML ES antigens of 62, 55, and 52 kDa. The results provide novel information on spatial larvae distribution in muscles and the humoral immune response of pigs exposed to two different doses of a Polish strain of T. britovi, extend knowledge on serological diagnostic tools which may be introduced in veterinary practice for the detection of T. britovi infections in pig production, and offer practical solutions for meat hygiene inspectors in the field at sampling sites when examining pig carcasses for Trichinella.

Content and Solubility of Collagen and Their Relation to Proximate Composition and Shear Force of Meat from Different Anatomical Location in Carcass of European Beaver (Castor fiber).

The content and solubility of collagen in the muscle tissue and cooked meat from three anatomical locations (loin, hind leg and shoulder) in carcasses of adult male European beavers and relationships of collagen fractions with proximate composition and shear force were studied. Shoulder muscle tissue contained the highest amount of intramuscular fat, collagen/protein ratio, total and insoluble collagen, and the lowest percentage of soluble collagen. The cooked meat from hind leg contained the lowest amount of total, soluble and insoluble collagen. The percentage of collagen fractions in cooked meat was comparable in all cuts (p > 0.05). The toughest meat was from the shoulder, followed by the hind leg, and the tenderest meat was from the loin (p < 0.01). Shear force of cooked meat was correlated positively with the amount of total collagen, insoluble collagen and its percentage in muscle tissue (0.597, 0.594 and 0.499, p < 0.01), as well as negatively with percentage of soluble collagen (−0.594, p < 0.001). No correlations between the shear force and the content of total collagen and its fractions in cooked meat were found. In conclusion, our results indicate that the amount of total collagen and its fractions in raw muscle tissue of beaver is a better tenderness predictor for cooked meat than their values in heat-treated meat.

A Food-Safety Risk Assessment of Mercury, Lead and Cadmium in Fish Recreationally Caught from Three Lakes in Poland.

Heavy metals are introduced into water due to anthropogenic activities and can significantly affect an entire ecosystem. Due to their close integration with the water environment, fish are a sensitive indicator of contamination. In addition, fish is an important element in human diets, therefore, monitoring the concentrations of metallic contaminants in their meat is particularly important for food safety. This study aimed to assess the pollution of water ecosystems with selected toxic heavy metals in lakes Dratów, Czarne Sosnowickie, and Syczynskie. The concentration of Pb, Cd, and Hg in water, sediment, and freshwater fish muscle tissue was determined, and a food safety assessment was performed. The analysis of water and sediments showed that the sediments were characterised by a significantly higher concentration of heavy metals. Presumably, this ecosystem element plays an important role in the uptake of heavy metal contaminants by fish whose levels were higher in planktonophagous and benthophagous fish species as compared to predatory fish. The food safety assessment showed that amounts of heavy metals in the muscle tissue posed no threat to the health of consumers ingesting that fish species, neither individually (THQ) nor collectively (TTHQ).

The Effect of L-Glutamine on Basal Albumen and Yolk Indices, and Albumen Amino Acids Composition.

The current study tested the hypothesis that 1.0% dietary inclusion of L-glutamine (Gln), an non-essential amino acid that influences protein synthesis, can improve internal egg quality, including amino acids profile. Thirty-week-old Bovans Brown laying hens in their middle laying period were assigned to one of the two experimental groups (12 replicate cages, 2 hens/cage) with Gln in the form of alpha-ketoglutarate (10 g/kg) or without Gln inclusion. The experimental period lasted for 30 wks, from the 31st to the 60th week of age of hens, when eggs were collected and selected egg quality indices were determined. Gln supplementation had no effect on albumen and egg yolk share, albumen and yolk basal indices and composition, including yolk cholesterol content. However, Gln decreased the lipid content of the egg albumen (p < 0.001), and influenced albumen amino acid profile, increasing content of asparagine (p < 0.05), phenylalanine (p < 0.05), proline (p < 0.001), tryptophan (p < 0.01), and tyrosine (p < 0.05). In conclusion, the study shows a potential role of Gln supplementation for enhancing nutritional values of eggs by lower lipid content and higher amino acid profile.

Distribution of Trichinella spiralis, Trichinella britovi, and Trichinella pseudospiralis in the Diaphragms and T. spiralis and T. britovi in the Tongues of Experimentally Infected Pigs.

There is little or even no data in the global literature on the distribution of different species of Trichinella in the individual parts of the diaphragms and tongues in infected pigs. This is of particular importance from the food safety point of view and for the conduct of routine testing of pig carcasses for Trichinella as well as epidemiological surveys. Therefore, the aim of the present study was to evaluate the distribution of Trichinella spiralis (T. spiralis), Trichinella britovi (T. britovi), and Trichinella pseudospiralis (T. pseudospiralis) ML in various parts of the diaphragm (the pillars, costal, and sternal part) and the distribution of encapsulated species of Trichinella (T. spiralis and T. britovi) in various parts of the tongues (the tip, body, and root) of experimentally infected pigs. The diaphragm pillars were the most heavily parasitized part of the diaphragm both in groups of pigs infected with particular species of Trichinella and in groups of pigs presenting different levels of infection; however, statistical differences were observed only in the group of pigs with moderate (21-35 larvae per gram-lpg) or moderately high (35-55 lpg) intensity of Trichinella spp. infection in the entire diaphragm. In all groups of pigs, regardless of the infecting Trichinella species or infection level, larvae showed a homogeneous distribution on both sides of the diaphragm and excluding those of T. pseudospiralis, also in all three parts of the tongue. Histological examination showed features of a differential inflammatory response around larvae of the different Trichinella species. This study confirmed that for mandatory examination of pig carcasses using a pooled-sample digestion assay in which each pig is intended to be represented by a 1 gram sample taken from the diaphragm pillars, if that tissue is not available, the mass of the sample taken from the remaining diaphragm parts (costal or sternal) should be at least double that from the pillars. Histological findings confirmed that the inflammatory pattern of pig muscles varies depending on the Trichinella species triggering the infection and is less intense in the case of infections with T. pseudospiralis than in infections with encapsulated species of Trichinella (T. spiralis and T. britovi).

Microbiological Changes in Meat and Minced Meat from Beavers (Castor fiber L.) during Refrigerated and Frozen Storage.

This study aims to evaluate the microbiological status, pH, and water activity of European beaver meat to establish its shelf-life and microbiological safety. In this study, the microbiological profiles of meat and minced meat obtained from the carcasses of beavers were investigated. Microbial evaluation of the chilled meat was performed within 24 h after hunting, on the 7th day and 14th day, and the evaluation of the frozen meat was made during the 11th week of storage. Meat samples were analysed for total viable count (TVC), psychrotrophic bacteria count (PBC), Enterobacteriaceae count (EBC), Escherichiacoli count (EC), total staphylococcal count (TSC), lactic acid bacteria count (LABC) and total yeast and mould counts (TYMC). Tests for the presence of pathogenic bacteria from the genus Salmonella and Listeria were also performed. Additionally, the pH and water activity were determined. The initial amount of TVC was 4.94 log CFU/g in meat samples and 4.80 log CFU/g in minced meat. After 14 days of storage, the TVC increased to 8.33 in meat samples and 8.08 log CFU/g in minced meat. Pathogenic bacteria such as Listeria and Salmonella were not found in the beaver meat tested. The microbiological state of meat stored frozen for 11 weeks was comparable to the state found in meat stored refrigerated for seven days regarding the number of microorganisms.

Occurrence of Listeria monocytogenes in Artisanal Cheeses from Poland and Its Identification by MALDI-TOF MS.

Listeria monocytogenes is a foodborne pathogen. A source of infection can be artisanal cheeses. Identification of the Listeria species is important for the protection of public health and the food industry. This study aimed to examine artisanal cheeses for the presence of L. monocytogenes and the effectiveness of the MALDI-TOF MS method in the identification of the L. monocytogenes isolates. A total of 370 samples of artisanal cheeses were examined. L. monocytogenes was found in 23 cheese samples (6.2%). The reliability of L. monocytogenes identification achieved by MALDI-TOF MS was varied, and the vast majority of the isolates (27/32) were identified only to the secure genus, probable species level. This study showed that (i) the occurrence of L. monocytogenes in the artisanal cheeses was at a higher level than that in the other EU countries, (ii) the standard of species identification of L. monocytogenes isolates from artisanal cheeses achieved by MALDI-TOF MS was not satisfactory and (iii) the presence of L. monocytogenes in artisanal cheeses remains a problem with regard to the food safety criterion and a potential public health risk.

Cholesterol Content, Fatty Acid Profile and Health Lipid Indices in the Egg Yolk of Eggs from Hens at the End of the Laying Cycle, Following Alpha-Ketoglutarate Supplementation.

The current study aimed to assess the effects of dietary alpha-ketoglutarate (AKG) supplementation to laying hens on the fatty acid (FA) profile and cholesterol levels of the egg yolk at the end of production cycle. The experiment was performed on forty-eight Bovans Brown laying hens randomly assigned to either a control group (CONT) or a group supplemented with AKG. The CONT group was fed the basal diet, and the AKG group was fed the basal diet plus 1.0% AKG from the 31st until the 60th week of age, when FA profile, fat and cholesterol content of the egg yolks were determined. No significant changes in the cholesterol and total fat content of the egg yolks were observed. However, there were positive (the decrease in n-6 FA and the increase in MUFA), and negative (decrease in PUFA and n-3 FA, increase in TI and n-6/n-3 ratio) changes in FA profile following AKG supplementation. In conclusion, it was shown that dietary AKG after a 30-week long supplementation influence FA profile in egg yolk and its nutritional value.

Snail Eggs as a Raw Material for the Production of a Caviar Substitute.

INTRODUCTION: Snail eggs can be the raw material for the production of a caviar substitute. The substitute varies from the original in caloric value and nutrient content which determine the nutritional value of every foodstuff. The present study aimed to determine and compare the nutritional value and protein quality of eggs from two subspecies of edible snail. MATERIAL AND METHODS: The chemical composition of the snail eggs i.e. Cornu aspersum maxima and Cornu aspersum aspersum was determined in accordance with international standards. In order to evaluate the protein quality of the eggs of the two studied snail subspecies, the chemical score (CS), and a reference protein were used. RESULTS: Significant differences in the content of water, ash, and carbohydrates, but comparable protein and fat contents and caloric values were found. CONCLUSION: The protein in the eggs of the snails was complete by the measure of the model adopted for this study, however, meeting the daily essential amino acid requirements of an adult would require an immense supply of both species' eggs. Snail eggs of the Cornu genus were characterised by much lower nutritional value in comparison with caviar and caviar substitutes.

Microbiological Quality of Farmed Grass Carp, Bighead Carp, Siberian Sturgeon, and Wels Catfish from Eastern Poland.

INTRODUCTION: The purpose of this study was to determine the microbiological quality of food fish and its safety for consumers. MATERIAL AND METHODS: The study included 24 fish representing grass carp, bighead carp, Siberian sturgeon, and wels catfish. Specimens were collected in winter. Aerobic bacteria, psychrophilic, Enterobacteriaceae, Staphylococcus spp., and E. coli counts were made, and the presence of Salmonella spp., L. monocytogenes, S. aureus, and other coagulase-positive staphylococci was investigated. RESULTS: The microbiological analysis showed a similar level of aerobic, psychrophilic, and Staphylococcus spp. contamination of the four fish species. The Enterobacteriaceae count was higher in the muscles of grass carp and bighead carp than S. sturgeon and wels catfish. No pathogenic bacteria such as Salmonella spp., E. coli, L. monocytogenes, Staphylococcus aureus, or other coagulase positive staphylococci were found in samples of the examined fish species. CONCLUSION: The fresh fish examined in this study were of good microbiological quality and there was no health risk for consumers.

Phagocytic and oxidative burst activity of phagocytic cells in peripheral blood and uterine washings in cows with clinical endometritis before and after intrauterine use of cephapirin and methisoprinol.

The aim of the study was to evaluate phagocytic and killing activity of phagocytic cells in blood and uterine flush of cows with endometritis before and after intrauterine (i.u.) administration of cephapirin and methisoprinol. The research was carried out on 28 cows with clinical endometritis. Animals were divided into four groups, each composed of seven cows, depending on the i.u. treatment used: Group A-cephapirin; Group B-methisoprinol; Group C-cephapirin and methisoprinol at the same time; and a control group-without medication. Using flow cytometry technique, the phagocytic activity of granulocytes and monocytes was identified, as well as the oxidative burst activity of neutrophils in the peripheral blood and uterine washings. Summarizing the results of the research, i.u. infusion of cephapirin caused a reduction in the phagocytic and killing activity of phagocytes. The i.u. use of methisoprinol increased phagocytic and killing activity of phagocytes in the uterus. Administering both listed substances simultaneously showed a decrease in phagocytosis, presumably due to the dominating inhibitor effect of the antibiotic. However, also an increase of mean fluorescence intensity was observed, presumably caused by the methisoprinol. Intrauterine use of immunostimulatory substances, can improve the effectiveness of the treatment of endometritis in cows.

Occurrence of gastrointestinal parasites in slaughter rabbits.

The aim of the study was to determine the occurrence of gastrointestinal parasites in slaughter rabbits managed in small scale farms and under industrial farming system. The research material included intestines and livers of rabbits slaughtered between years 2007 and 2011. The rabbit carcasses submitted to parasitological examination had passed the sanitary veterinary inspection as fit for human consumption. The samples were collected in spring and autumn seasons. The studies showed no effect of a rabbit farming system, season of the year, or differences in an invasion type in each year. The parasitological test recognized exclusively mixed infestation diagnosed in 79.56% of the studied animals. Parasitological evaluation of the rabbit internal organs identified the invasions of coccidia (78.83%), nematoda (16.42%), cestoda (0.72%), and cysticerci Cysticercus pisiformis (4.74%). Coccidian invasions found in intestines were dominant, and their prevalence reached 56.48%, while the hepatic coccidian extensity was markedly lower, i.e., 3.34% of the examined rabbits. Invasions were characterized by low intensity. The studies recognized invasions of nematoda (Obeliscoides cuniculi, Graphidium strigosum, Trichostrongylus sp., Strongyloides sp., Passalurus ambiguus, Trichuris leporis), cestoda (Mosgovoyia pectinata), and cysticerci C. pisiformis.