Effect of VP, MAP and combined packaging systems on the physicochemical properties and microbiological status of veal from unweaned calves.

The packaging system is one of the factors influencing the preservation of the nutritional value, microbiological safety, and sensory attributes of meat. The study investigated changes in physicochemical and microbiological properties taking place during 15-day refrigerated storage of two calf muscles, the longissimus lumborum (LL) and semitendinosus (ST), packaged in three systems, respectively, vacuum packing (VP), modified atmosphere packaging (MAP, 80% O2 + 20% CO2), and a combined system (VP + MAP, 8 d in VP followed by 7 d in MAP). LL and ST stored in VP had significantly lower levels of lipid oxidation, higher α-tocopherol content, and higher instrumentally measured tenderness in comparison with the samples stored in MAP. On the other hand, the MAP samples had lower purge loss at 5 and 15 days, a higher proportion of oxymyoglobin up to 10 days of storage, and a better microbiological status. Calf muscle samples stored in the VP + MAP system had intermediate values for TBARS and α-tocopherol content and at the same time were the most tender and had the lowest counts of Pseudomonas and Enterobacteriaceae bacteria at 15 days. All packaging systems ensured relatively good quality of veal characteristics up to the last day of storage. However, for MAP at 15 days of storage, unfavourable changes in colour (a high level of metmyoglobin and a decrease in oxymyoglobin, redness and R630/580 ratio) and in the lipid fraction (a high TBARS value and a significant decrease in α-tocopherol content) were observed.

Interleukin-6 as a Milk Marker of Clinical and Subclinical Intramammary Infections (IMI) in Cows Caused by Streptococcus spp.

The aim of the study was to evaluate the concentrations of Interleukin-6 (IL-6) in milk and serum of healthy cows (HE) and cows with mastitis caused by Streptococcus spp. The blood and milk samples were obtained from Holstein-Friesian cows (Lublin region, Poland). A total of 43 milk and serum samples from 28 cows with mastitis and 15 healthy cows were selected for study. IL-6 levels in milk from HE cows ranged from 6.09-80.24 pg/mL (median 26.6 pg/mL) and were significantly lower than in milk from both cows with clinical and subclinical mastitis (487.09 pg/mL vs. 26.6 pg/mL in CM, p < 0.001; and 165.31 pg/mL vs. 26.6 pg/mL in SCM, p < 0.001). The IL-6 concentration in the serum of HE was not significantly different from the serum IL-6 of the entire group of mastitis cows, regardless of whether the inflammation proceeded in a clinical or subclinical form (44.37 pg/mL vs. 78.09 pg/mL; 128.29 pg/mL vs. 78.09 pg/mL, respectively). The present study indicates that cows with mastitis caused by Streptococcus spp. develop a local immune response in the mammary gland in response to the pathogen. Monitoring of IL-6 levels in milk can allow early detection of mastitis, which is especially important in cases of subclinical inflammation.

Occurrence of Campylobacter in Faeces, Livers and Carcasses of Wild Boars Hunted in Tuscany (Italy) and Evaluation of MALDI-TOF MS for the Identification of Campylobacter Species.

A total of 193 wild boars hunted in Tuscany, an Italian region with a high presence of wild ungulates, were examined to assess the occurrence of Campylobacter species in faeces, bile, liver and carcasses, with the aim of clarifying their contribution to human infection through the food chain. Campylobacter spp. were found in 44.56% of the animals, 42.62% of the faecal samples, 18.18% of the carcass samples, 4.81% of the liver tissues and 1.97% of the bile samples. The Campylobacter species genotypically identified were C. coli, C. lanienae, C. jejuni and C. hyointestinalis. The prevalent species transpired to be C. coli and C. lanienae, which were isolated from all the matrices; C. jejuni was present in faeces and liver, while C. hyointestinalis only in faeces. Identification was carried out by matrix-assisted laser desorption/ionisation-time-of-flight mass spectrometry (MALDI-TOF MS) on 66 out of 100 isolates identified genotypically, and the technique yielded unsatisfactory results in the case of C. lanienae, which is responsible for sporadic human disease cases. The level of Campylobacter spp. contamination of meat and liver underlines the need to provide appropriate food safety information to hunters and consumers.

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.

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.

Acute phase protein pattern and antibody response in pigs experimentally infected with a moderate dose of Trichinella spiralis, T. britovi, and T. pseudospiralis.

The aim of the present study was to evaluate the acute-phase protein (APP) response in three groups of pigs experimentally infected with a moderate infective dose, i.e. 1000 muscle larvae (ML) of Trichinella spiralis, 3000 ML of Trichinella britovi, and 2000 ML of Trichinella pseudospiralis. Over a 62-day period of infection, we examined the serum level and kinetics of the haptoglobin (Hp), C-reactive protein (CRP), serum amyloid A (SAA), and pig major acute-phase protein (pig-MAP). In addition, to better understand the immune response of pigs experimentally infected with three different species of Trichinella, the kinetics of IgG and IgM antibodies against excretory-secretory (ES) antigens of Trichinella ML were also investigated. In order to assess anti-Trichinella IgG dynamics, we used a commercial and an in-house ELISA based on both heterologous (T. spiralis) and homologous (T. spiralis, T. britovi, and T. pseudospiralis) Trichinella species ES antigens. Among the four APPs analyzed, the concentration of CRP and pig-MAP significantly increased only in T. britovi-infected swine when compared with control pigs. This took place as early as 6 days post-infection (dpi). Hp was the only APP whose concentration significantly increased in pigs infected with T. pseudospiralis, this occurring as late as on day 62 pi. Despite the statistical differences found, increases in pig-MAP, CRP, and Hp levels were rather mild and transitory; none of these proteins were found to be elevated in the serum of all experimental groups of pigs at the same time point after infection. Specific IgG antibodies against ES antigens of Trichinella ML were first detected by the commercial and in-house T. spiralis ML ES-antigen ELISAs on days 30, 36 and 36 pi in pigs experimentally infected with T. spiralis, T. britovi, and T. pseudospiralis, respectively. However, seroconversion in pigs experimentally infected with T. britovi was detected slightly earlier (30 dpi) when the ELISA based on homologous rather than heterologous ES antigens was applied. In serum samples from pigs infected with T. spiralis, statistically significant increases in the level of specific IgM antibodies against T. spiralis ML ES antigens were first detected on day 30 pi and after this time, their concentration began to decrease. No changes in the level of anti-Trichinella IgM were observed in T. britovi- or T. pseudospiralis-infected pigs throughout the entire period of the experiment.

Fatty Acid Profile in Edible Eggs of Snails from the Cornu Genus.

INTRODUCTION: The aim of this study was to determine the content of fatty acids in eggs harvested from two edible subspecies of Polish-bred common garden snail from the Cornu genus, as well as this content in the retail-ready product obtained from these eggs. MATERIAL AND METHODS: Material for the study consisted of eggs from two subspecies of edible snails: the small (Cornu aspersum aspersum), and large (Cornu aspersum maxima) common garden snails. The eggs studied were in two forms, the first of which had undergone initial processing to the half-product stage and the second of which was the final product available on the Polish market under the name "Snail Eggs". The gas chromatography method was used to determine the content of fatty acids. RESULTS: More than 75% of the studied fats were saturated fatty acids, dominated by palmitic and stearic acids. The average content of polyunsaturated fatty acids was 0.37%, and it was a combination of two acids: linoleic (C18:2n6c), and its trans isomer (C18:2n6t). No significant differences were found comparing individual fatty acids content between the two species' eggs as half-products, or between the half-products and the final product. CONCLUSION: The fat in raw and processed eggs of common garden snails holds low nutritional value, and the processing did not affect the content of fatty acids.

Fatty Acid Profile in Fat Obtained from Edible Part of Land Snails Harvested in Poland.

INTRODUCTION: The objective was to determine the content of fatty acids in edible snail fat by snail species, collection site, and processing stage. MATERIAL AND METHODS: The research material comprised 180 edible fat samples from the three genera of edible snails collected in Poland: free-living Helix pomatia (HP) and two cultivated Cornu subspecies: C. aspersa maxima (CAM) and C. aspersum aspersum (CAA). All snails came from the Greater Poland and Lower Silesian Provinces: HP from their natural habitat and CAM and CAA from heliciculture farms. The studies focused on the raw meat, cooked meat, and frozen meat processing stages. Fatty acid (FA) profiles were determined by the gas chromatography method. RESULTS: Helix pomatia fat showed a higher saturated fatty acid (SFA) content, whereas the fat of Cornu genus snails had a higher unsaturated fatty acid (UFA) component, i.e. monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA). Thermal processing of snail meat increased all the determined SFA and decreased all the PUFA values, and increased the content of C18:1, C20:1, and C22:1 acids in the MUFA group. The material collection site had limited impact on FA content as differences were noted only in levels of C18:1, C18:2 n6, and C20:5. The differences pertained only to the fat of farmed snails of the Cornu genus. CONCLUSION: Due to the high content of UFA and a favourable ratio of n6:n3 acids and PUFA:SFA, snail fat can be regarded as nutritionally valuable.

Selenium, Copper, and Zinc Concentrations in the Raw and Processed Meat of Edible Land Snails Harvested in Poland.

INTRODUCTION: The objective of the present research was to carry out a comparative assessment of copper, zinc, and selenium concentrations in the meat of edible land snails collected in Poland (Helix pomatia, Cornu aspersum maxima, and Cornu aspersum aspersum), as well as to determine the effect of preliminary processing of Roman snails (Helix pomatia) on the content of the aforementioned elements. MATERIAL AND METHODS: In the first stage, determinations were made on unprocessed snail meat. In the second stage, the study focused on Roman snails and consisted in an additional evaluation of frozen meat after full processing. Zinc and copper contents were determined by flame atomic absorption spectrometry and the selenium content was established by graphite furnace atomic absorption spectrometry. RESULTS: The selenium content differed significantly among all three species. The copper content in Roman snails differed significantly from that in farmed snails. No significant difference in the zinc level was noted among the three snail species. The selenium content in raw and processed meat of Roman snails did not show any significant difference while the copper and zinc level was significantly higher in processed meat samples. CONCLUSION: The present research on the meat of edible snails showed different levels of selenium, copper, and zinc, depending on the species, collection site, and subjection to processing.