Main aim of this research was to trace the development of volatile profile of Kumpiak podlaski dry-cured ham during traditional curing and ripening for 30 weeks. Volatiles were extracted from each 6-week period of ripening, and overall fifty-three aroma compounds were identified. Changes in chemical groups share between cured and fully ripened ham were observed: aldehydes (35.49 ? 31.37%), ketones (25.18 ? 14.62%), alcohols (17.97 ? 15.74%), esters (3.37 ? 12.04%), hydrocarbons (7.69 ? 6.81%), fatty acids (0.02 ? 0.53%), terpenes (2.26 ? 9.70%) and heterocyclic aromatic compounds (0.99 ? 0.78%). The 18th week of ripening is crucial for the aroma of Kumpiak podlaski ham due to start of continuous decrease in ketones and increase in esters' and terpenes' share. Formation of esters and terpenes originated from the presence of local herbs and the development of microflora. Principal component analysis (PCA) showed clear separation of samples from each 6-week period of ripening. Obtained results relying on thirty-seven compounds enabled to make a preliminary determination of ripening markers.

Background. The aim of this paper was to assess the inhibitory properties of salts of phenolic acids against Escherichia coli O157:H7 ATCC 8739. Escherichia coli O157:H7 is a pathogen which is able to produce verotoxins provoking hemorrhagic diarrhea in humans. There is a strong need for the effective natural methods eliminating E. coli O157:H7 from food. Methodology. The following salts were tested: sodium, potassium and lithium salts of ortho-coumaric, meta-coumaric and para-coumaric acids. The 1%, 2%, 3%, 4% and 5% water solutions of each substance were prepared. Agar-well diffusion method was applied. Petri dishes were incubated at 35°C for 24 h. At the end of the incubation period, inhibition zones which appeared on the medium Petri dishes were calculated in millimeters. Results. It was found that lithium salt of o-coumaric acid, potassium salt of o-coumaric acid, lithium salt of m-coumaric acid and sodium salt of m-coumaric acid were most effective towards E. coli O157:H7, while potassium salt of m-coumaric acid, a sodium salt of p-coumaric acid were slightly less effective and lithium salt of p-coumaric acid did not possess any antimicrobial activity. Conclusion. The salts of phenolic acids having various structural features showed different characteristics towards foodborne pathogens. Such fi ndings indicate that phenolic acids and their salts may be a potential bio-alternative for chemical food preservation.

The applicability of the spray-dried whey for the production of reduced-calorie mayonnaise-type emulsions was studied. Whey was used as a stabilizing/emulsifying agent and as a fat-replacement component. Whey powder was spray-dried at 130, 140, and 180 C. As control sample, 80% w/w standard fat emulsion was prepared. Mayonnaise-like fat-reduced emulsions contained 65% w/w of fat and 15% w/w of three distinct types of whey. The destabilization of the emulsions was investigated within 7 days of storage by scanning the samples with laser light. Backscattering, Turbiscan stability index, elasticity index, and macroscopic viscosity index were determined. The most stable emulsion contained whey powder spray-dried at 180 C. The emulsion made with whey powder spray-dried at 130 C was less stable than that with 180 C spray-dried whey, but it was more stable than the control and the one with whey spray-dried at 140 C.

The application of DNA-based methods enables to identify Yersinia enterocolitica carrying the ail-gene with a greater sensitivity compared to culture methods and biochemical tests used for detection of pathogenic Y. enterocolitica in animal and food samples. In this study, 100 samples of pig tonsils were examined, among which 17 were positive for the ail gene. Additionally, biochemical tests and RT-PCR showed that nine Y. enterocolitica isolates carried the ail-gene. Two Y. enterocolitica isolates of 1A biotype had the ail gene. The results demonstrated the usefulness of RT-PCR method applied for detection of potentially pathogenic, possessing the ail gene Y. enterocolitica in the material examined.

The first objective of this work included the development of real-time polymerase chain reaction (RT-PCR) which is also known as quantitative polymerase chain reaction (qPCR) assays to quantify two species of lactic acid bacteria which play a very important role in cheese ripening: Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus. The second objective was the comparison of qPCR and plate counts of these two species present in raw cow’s milk cheese samples during different stages of ripening. Thirty-three deoxyribonucleic acid (DNA) samples coming from seven different bacterial species, which were phylogenetically related or commonly isolated from raw milk and dairy products, were chosen as positive and negative controls. The qPCR assays showed a high quantification capacity characterised by their linearity (R2 > 0.998), PCR efficiencies which were within the range 78.0–90.0% for L. delbrueckii subsp. bulgaricus, and 93.6–100.5% for S. thermophilus, and quantification limit (103 gene copies/ml for L. delbrueckii subsp. bulgaricus and 10 gene copies/ml for S. thermophilus). The importance of our study is in the monitoring of changes in populations of L. delbrueckii subsp. bulgaricus and S. thermophilus contributing to cheese ripening using the newly designed qPCR assay.