Agro-industrial by-products are promising source of biopolymers, including proteins and polysaccharides. This study was designed to evaluate the flaxseed oil cake extract (FOCE) as natural encapsulating material and carrier for probiotic Lacticaseibacillus rhamnous GG (LGG). The powders were obtained using three spray drying inlet temperatures (110 °C, 140 °C, 170 °C), and reconstituted. The influence of temperature on water activity, morphology, chemical composition, flowability and cohesiveness of the powders was estimated. For all variants, the survival of bacteria during spray drying, and simulated passage through the gastrointestinal tract was evaluated. The preservation of LGG probiotic features such as cholesterol reduction, hydrophobicity and adhesion to mucin were examined. Results revealed that all physicochemical and functional characteristics of the powders were affected by the inlet temperature. This study demonstrated that FOCE is an appropriate matrix for spray drying (due to flaxseed proteins and polysaccharides) providing high survivability of bacteria (89.41–96.32%), that passed meaningfully through the simulated gastrointestinal tract (4.39–5.97 log reduction), largely maintaining their probiotic properties, being a promising environmentally-friendly carrier for probiotic LGG.

The objective of the study was to determine the effects of probiotic bacteria Bacillus licheniformis and Bacillus subtilis on microbiological properties of feed mixtures and on the digestive tract content as applicable to production traits and carcass characteristics of fatteners. The experiment was performed on 83,838 fatteners from four successive (insertions) productions in two groups. From the seventy eighth day of age till marketing to the slaughter plant, the pigs were supplied with BioPlus YC probiotic (Chr. Hansen) in the amount of 400 g/t. The preparation contained a complex of probiotic bacteria Bacillus licheniformis DSM 5749, and Bacillus subtilis DSM 5750 spores in a 1:1 ratio. From the fourth insertion, after reaching a body weight of approximately 112 kg, 60 fatteners were selected from each group to measure carcass quality and half of them for meat quality evaluation. Moreover, microbiological analyses in feed and colon were performed. The study showed that BioPlus YC probiotics supplementation resulted in a significantly higher count of B. subtilis and B. licheniformis in the feed, a higher count of B. subtilis, B. licheniformis and LAB, as well as a lower count of Enterobacteriaceae, Enterococcus, Clostridium and Bacillus sp. in the mucosa and in the colorectal content of the test pigs. Our work has shown that supplementation with the BioPlus YC probiotic had a positive effect on the production traits of pigs mainly by reducing mortality (2.83%, p = 0.010), lowering feed conversion ratio—FCR (2.59 kg/kg, p = 0.013), better average daily gain—ADG (0.95 kg/day, p = 0.002) and shorter fattening period (77.25 days, p = 0.019) when compared to the control group (4.19%; 2.79 kg/kg; 0.89 kg/day; 92.8 days, respectively). The addition of the specific Bacillus bacteria did not influence carcass and meat characteristics of the test fatteners.

Our objective was to assess the enterotoxigenic potential of coagulase-negative staphylococci (CNS) isolated from bovine milk in Poland. We analyzed CNS isolates collected from 133 bovine milk batches from dairy farms in the Western Pomerania district during 2 milking seasons. A total of 163 isolates were screened by multiplex/duplex PCR for the presence of 18 of 25 enterotoxin genes identified so far in Staphylococcus aureus. The CNS strains presumed to be potentially enterotoxigenic were identified at the species level based on MALDI-TOF mass spectrometry analysis. Based on the presence of an amplicon matching D, G, or O enterotoxin genes, we initially identified 32 of the 163 CNS isolates tested as potentially enterotoxigenic. However, only 8 of these strains were confirmed as such. All 8 of these CNS strains, identified as Staphylococcus haemolyticus, harbored the seg genes, a prerequisite for enterotoxin G production, but so far not connected with staphylococcal foodborne poisoning cases. None of the CNS bovine milk isolates tested was a potential producer of classical A to E staphylococcal enterotoxins. Results of our surveys revealed a low prevalence of enterotoxigenic CNS among the milk isolates from dairy farms in the Western Pomerania district, Poland, suggesting that they pose only a mild health risk in milk. In our opinion, confirmed formation of nonspecific amplicons leading to false-positive results excludes multiplex/duplex PCR as the sole method for assessing the enterotoxigenic potential of CNS.

The main problem in processing bovine colostrum is preserving as many beneficial compounds as possible, most of which have low thermal stability. The present study evaluates the possibility of using cold plasma (CP) as a decontamination technology and its effect on selected biologically active fractions of freeze-dried bovine colostrum. The plasma process was carried out in air, nitrogen, and oxygen environments. The results revealed that the sterilization process using CP caused slight changes in the colour of the samples expressed by the attributes ΔC, ΔL, Δh and ΔE. The decontamination effect depended on the gas used and the type of microorganism. The highest decontamination effects were gained under oxygen conditions, where reductions were obtained for total psychrophilic bacteria (THPC) by log 1.24, mesophilic bacteria (THMC) by log 1.02, Enterobacteriaceae by log 1.16, E. coli by log 0.96, yeast (TYMC) by log 0.92. A significantly lower decontaminating effect was obtained for Gram-positive bacteria and sporophytic forms. Additionally, the application of CP, regardless of the gas used, affected the modification of protein structure and reduction of immunoglobulin concentration. as proven by proteomics analyses (1-DE, 2-DE, MALDI–TOF MS). The same applied to β-lactoglobulin in air and oxygen and BSA in nitrogen and air.

Background. In times when there is a growing interest in ready-to-eat food (RTEF), the presence of potentially pathogenic bacteria, including the toxigenic psychrotolerant bacilli from the B. cereus group, on this type of carrier may pose a real threat to the health of consumers. A significant part of RTEF is represented by vegetable products and food products made with them. The increased production of convenience foods has resulted in their international turnover growing. When coupled with a rising percentage of persons from risk groups (YOPI), including the elderly or immunocompromised, this may mean increased health risks posed by the so-called "novel pathogens", like the toxigenic psychrotolerant B. cereus sensu lato. Materials and methods. Food samples were analyzed for the presence and count of putative B. cereus according to the Polish Standard PN-EN ISO 7932:2005. All genetic analyses were conducted using a qualitative real-time PCR. Results. The presence of B. cereus sensu lato was confirmed in 130 out of the 192 samples of convenience foods, at contamination levels ranging from 1.65 to 3.32 log CFU/g. Among the strains confirmed to belong to the B. cereus group, 23 were identified as emetic B. cereus. The analysis of each strain's ability to grow at temp. 4-10 degrees C demonstrated that 4.9% and 12.7% of the isolates were able to grow at 4 degrees C and 6 degrees C, respectively. In turn, 15.2% were able to grow at 8 degrees C, and 36.3% at 10 degrees C. None of the psychrotrophic strains possessed genes typical of B. weihenstephanensis. The group of psychrotrophic B. cereus included potentially toxigenic strains being carriers of genes that determine the synthesis of the following toxins: NHE, HBL, CytK, and cereulide. Some of them were potent enough to produce more than one toxin. Conclusions. The analyses conducted in this study demonstrate that the psychrotolerant strains of B. cereus (including the toxigenic ones) are frequent microbiological contaminants of RTEF products offered in retail. The presence of emetic strains from the B. cereus group, which are able to grow in a wide range of temperatures and produce enterotoxins and enzymes with the characteristics of toxins, in ready-to-eat foods may pose a real threat to consumer health.

Background. The aim of this study was to evaluate selected probiotic preparations for determining the abundance and species affiliation of the strains contained in them. To meet the assumed objectives of this study, ten different preparations sold retail were used. The evaluation included a quantitative and qualitative analysis. The quantitative analysis was carried out using culture methods, which also allowed for the initial determination of the microbiota diversity of the preparations tested and the isolation of strains for further study. Results and conclusion. A total of nine bacterial strains and two yeast strains were isolated. The qualitative analysis included biochemical tests using API® 50 CHL and API® ID 32 C tests, as well as a genetic analysis. Genetic identification was performed using the PCR technique with agarose gel electrophoretic separation of products. A pair of primers was used to identify yeast strains: ITS1 (5'-TCC GTA GGT GAA CCT GCG G-3') and ITS4 (5'-TCC TCC GCT TAT TGA TAT GC-3'), which allowed to confirm their species affiliation to Saccharomyces cerevisiae. Genetic identification of bacteria of the genus Lactobacillus was carried out using primers 27F (5'-AGAGTTTGATCCTGGCTCAG-3') and 1492R (5'-GGTTACCTTGTTACGACTT-3'). Only three of ten preparations met all declarations specified on the packaging, relating to the number of strains, their species affiliation and the number of CFUs in a single dose of the product. For one preparation, one bacterial strain not mentioned in the declaration was isolated, and one diet supplement showed <104 cfu / dose of live microorganisms. For three preparations, one of the declared bacterial strains was not isolated.