Општи хигијенски параметри и одабрани бактеријски патогени у производњи ферментисаних сувих кобасица у Србији уз испитивање ефеката термичких третмана / General hygienic parameters and selected bacterial pathogens during production of Serbian dry fermente

The main aim of this doctoral thesis was to investigate the general characteristics of industrially-produced Serbian dry fermented sausages and the possibility of further improving their microbiological safety. Microbiological and physicochemical indicators were studied along the industrial production chains producing Sremska and Sudzuk sausage, typical of dry, fermented sausage prepared from pork or beef, respectively. The occurrences of Salmonella in pork sausages, and of Escherichia coli O157 in beef sausages were determined. Changes in the main groups of microbiota, pH, aw values and the chemical composition of the products were evaluated. Microbiological contamination in the initial stages of production was generally high. Salmonella was confirmed from the batter-preparation phase in two of three production lines, while E. coli O157 was confirmed in one sample of meat and fatty tissue from one production line. The results of this investigation of sausage production were similar to results obtained in other countries. All samples of finished pork sausage were of acceptable microbiological quality, while the majority of beef sausage samples were not microbiologically acceptable. The initial presence of foodborne pathogens can be considered a food safety risk. The survival of Salmonella Тyphimurium, Escherichia coli O157 and Listeria monocytogenes during production and storage of inoculated pork and beef sausages was determined in the second phase of the investigation. All three pathogens declined in numbers in accordance with data from the literature, and it can be concluded that normal measures for pork and beef sausage preparation in industrial production do not always ensure, to a suitable level, the microbiological safety of the products. The possibility of pasteurising finished pork and beef sausages, with the aim of reducing Salmonella Typhimurium and E. coli O157, respectively, was investigated, and at the same time, sensory evaluation of product quality was performed. The results showed that pasteurisation eliminated Salmonella Typhimurium and E. coli O157 from finished dry fermented sausages, while sensory qualities of the products remained acceptable. L. monoctogenes proved to be a significantly more heat-resistant pathogen in both types of sausage, and therefore, further research is required to determine how to reduce numbers of this pathogen to acceptable levels.