Edible chitosan-alginate based coatings enriched with turmeric and oregano additives: Formulation, antimicrobial and non-cytotoxic properties.

In our study we developed the edible chitosan and alginate coatings with turmeric or oregano additives. The objective of the research was to evaluate the dose-dependent cytotoxicity of films. In cell line studies on HepG2 and BJ cells, they were shown to be non-cytotoxic materials (IC50% was not reached). For HepG2 increase in cell proliferation was observed for 3, 4, and 7 mg/mL of OS3 (124,79±9,21; 162,4±10,46; 165,37±18,44) after 72 h. In BJ cells, no significant decrease in proliferation was noted after 24- and 48-hour exposure to OS0 and OS1 (1-7 mg/ml). The addition of oregano (1% v/v) resulted in films with higher elongation at break and 40% higher tensile strength compared to the base (OS0) film. Use of additives significantly increased the thermal stability of the complexes (by an average of 10 °C). Coatings were tested on tofu and had proven potent antimicrobial properties.

Staphylococcal Enterotoxin Genes in Coagulase-Negative Staphylococci-Stability, Expression, and Genomic Context.

In the current study, we screened a collection of coagulase-negative staphylococci (CoNS) isolates for orthologues of staphylococcal enterotoxins (SEs) involved in S. aureus-related staphylococcal food poisoning (SFP). The amplicons corresponding to SEs were detected in S. chromogenes, S. epidermidis, S. haemolyticus, S. borealis, S. pasteuri, S. saprophyticus, S. vitulinus, S. warneri, and S. xylosus. All amplicons were sequenced and identified as parts of known S. aureus or S. epidermidis SE genes. Quantitative real-time PCR allowed determining the relative copy number of each SE amplicon. A significant portion of the amplicons of the sea, seb, sec, and seh genes occurred at low copy numbers. Only the amplicons of the sec gene identified in three isolates of S. epidermidis displayed relative copy numbers comparable to sec in the reference enterotoxigenic S. aureus and S. epidermidis strains. Consecutive passages in microbiological media of selected CoNS isolates carrying low copy numbers of sea, seb, sec, and seh genes resulted in a decrease of gene copy number. S. epidermidis isolates harbored a high copy number of sec, which remained stable over the passages. We demonstrated that enterotoxin genes may occur at highly variable copy numbers in CoNS. However, we could identify enterotoxin genes only in whole-genome sequences of CoNS carrying them in a stable form at high copy numbers. Only those enterotoxins were expressed at the protein level. Our results indicate that PCR-based detection of enterotoxin genes in CoNS should always require an additional control, like analysis of their presence in the bacterial genome. We also demonstrate S. epidermidis as a CoNS species harboring SE genes in a stable form at a specific chromosome site and expressing them as a protein.

Biochemical Properties Affecting the Nutritional Quality, Safety, and Aroma of Dry-Cured Products Manufactured from Meat of Rare Native Pig Breeds.

The aim of study was to compare the biochemical properties affecting the nutritional quality, safety, and aroma of dry-cured products manufactured from valuable meat of rare native pig breeds: Pulawska (Pul) and Zlotnicka Spotted (ZS). The count of lactic acid bacteria (4.4 log cfu/g) and the release of palmitic (23.1% and 25.9%), oleic (44.1% and 42.2%), and linoleic acids (8.3% and 7.8%), as well as arginine (30.0 and 44.3 mg/kg), histidine (25.8 and 20.6 mg/kg), and lysine (26.8-22.9 mg/kg), shaped the final pH (5.3 and 5.4) in Pul and ZS products during the 4 week maturing, respectively. Lastly, Pul and ZS meat differed in the proportion of decanoic, lauric, stearic, arachidic, and conjugated linoleic acids. The high content of putrescine (23.7 mg/kg), cadaverine (54.3 mg/kg), and tyramine (57.2 mg/kg), as well as a twofold greater share of histamine (163.2 mg/kg) and tryptamine (9.1 mg/kg), indicated a more advanced decarboxylation of ZS meat. Volatile compounds differentiating Pul and ZS meat were primarily hexanal, 3-hydroxybutan-2-one, phenylacetalaldehyde, 2,3-dimethyl-2-cyclopenten-1-one, 2-cyclopenten-1-one, and 3-methyl- and 2-cyclopenten-1-one. Most marked volatile compounds were obtained as a result of microbial activity (acetic acid, 3-methylbutan-1-ol, ethanol, acetone, and 3-hydroxybutan-2-one), advanced lipid oxidation, and decomposition of secondary oxidation products (hexanal, phenylacetaldehyde, and 2-cyclopenten-1-one).

Sensory quality of selected raw ripened meat products.

BACKGROUND: A demand on raw fermented meat products depends on their availability, price and the culture. In Poland, raw meat products have a several hundred years, although limited to the Podlasie region, tradition of manufacturing. Therefore, in spite of widening of Italian, Spanish, Portuguese, German and recently even the Czech Republic products assortment on the Polish market, the consumption of them increases slowly. The aim of the study was to compare the sensory quality of raw ripened smoked products and sausages, sold on the Polish foodstuffs market as "traditional". MATERIAL AND METHODS: The study included the basic chemical content, water activity, pH, the amount of lactic acid bacteria and coagulase-negative cocci, as well as selected texture and sensory parameters. The analysis was conducted in compliance with Polish Standards, and the cutting strength was measured with the use of the TA-XT2 texture-meter. The sensory analysis was conducted by a 12-person panel using the 5-point method. RESULTS: The differences in the amount of water, protein, fat and salt resulted from the wide variability of ingredients among both groups of the analysed cold meats. The smoked products were characterised by a higher pH (5.6-5.9), smaller amount of bacilli (2-5.5 log cfu/g) and lactic cocci (3.3 to 6.6 log cfu/g) in comparison with the sausages. The amount of both populations of bacteria in the sausages of a pH of 4.5-5.5 ranged from 6.8-8.9 log cfu/g and 5.9-7.7 log cfu/g, respectively. Among the analysed smoked products and sausages the greatest TPA hardness (respectively 128.6-140.3 N and 91.3-139.7 N), TPA chewiness (28.9-54.2 N and 16.1-36.0 N) and cutting strength (11.0-12.9 kG and 8.2-8.5 kG) was observed in those with a 0.81-0.86 water activity. The overall quality of the analysed cold meats was at a good level (3.9-4.1 pt). CONCLUSIONS: Distinguishing features which determined the quality of products are hardness, juiciness as well as odour. The specific odour of the yeast cultures present on the surface of the products, the high fat content which undergoes oxidation during ripening, a high salt content, the domination of pepper among the range of spices as well as the detection of lactic and acetic acid are not accepted by Polish consumers.