Listeria monocytogenes is ubiquitous bacteria. It causes listeriosis, a serious infectious disease which occurs as consequence of consumption of food contaminated with this pathogen bacterium. The frequency of incidence of listeriosis is low (1%), but with high mortality rate (30%). In certain countries (USA and Switzerland) large outbreaks of listeriosis were associated with consumption of fresh cheeses and milk. Studies on presence of L.monocytogenes in raw milk, carried out in Europe, have shown that 2,5-6% of samples can be contaminated with L.monocytogenes. In the process of production of milk and dairy products, it most commonly occurs as consequence of post-pasteurization contamination. L.monocytogenes has the ability to multiply and grow at low temperatures (4 0 C) and to survive even on freezing temperatures, and as such poses risk for health of consumers, if found in milk, cheese, ice-cream and other dairy products. In order to prevent the contamination of product with this bacterium, producers much implement prevention measures, and special attention must be focused on critical points in the production process and adequate sanitation. The general characteristics of L.monocytogenes, are presented in the study, also its resistance to environment, some listeriosis outbreaks, its presence in milk and dairy products and major hygiene measures.

In this paper the results of the analysis of the milk somatic cell count are presented, as well as correlation between the somatic cell count and content of certain chemical parameters in milk (milk proteins, fat, lactose and dry matter without fat) determined in collective samples of milk obtained from cows reared in intensive rearing system, during two production years. The research was carried out by control of collective milk samples from cows reared on family holdings. Somatic cell count, as well as the chemical quality of milk, were controlled daily in the laboratory for raw milk in dairy plant AD "Mlekara"-Subotica using the apparatus CombiFoss 6200 FC. In this investigation, statistically significant correlation (P<0,001) between all observed milk parameters was determined. Positive, weak and statistically highly significant correlation between the content of milk fat and proteins in milk and somatic cell count was established. It was also established that the variability of chemical parameters of milk and somatic cell count is also under the influence of different factors, such as: month of control, year of the research and farm.

Summary The aim of this study was to investigate aflatoxin M1 (AFM1) transfer from naturally contaminated raw milk into cheese and whey, during the production of Livanjski cheese (hard cheese type). Raw milk samples were collected from 4 farms in Serbia. The samples were then tested for AFM1 content and were later used for hard cheese production. Four cheese samples were produced, and the matching whey samples were also collected. The milk samples included two samples containing AFM1 above the EU maximum level (0.077±0.009 and 0.118±0.008 µg/kg) and the other two samples below the maximum level of 0.05 µg/kg (0.021±0.002 and 0.034±0.004 µg/kg). Regarding AFM1 transfer into cheese from the milk samples containing AFM1 above the EU maximum level, the rate was approximately 4-fold (383% and 410%). On the other hand, in the cheese samples made from milk containing AFM1 below the EU maximum level, almost 10-fold levels of AFM1 content in milk were found (transfer rates of 934% and 961%). As for the whey samples, AFM1 levels were below the levels found in the milk samples (transfer rates of 78%, 74%, 68% and 57%). The difference in the transfer rates for the cheese made from the milk samples contaminated at different levels may indicate the possibility that the AFM1 transfer rate from milk into cheese depends on the content of this toxin in milk.

Organic cheeses are value added products that provide small dairy farmers with a viable source of income and has the potential to revitalize farms, provide new jobs, and develop new cheese varieties with unique flavours for consumers to experience. Production of hard organic cheese must comply with organic standards and regulations of organic production. Whole organic milk that does not contain residues of pesticides, hormones and antibiotics represents a quality raw material for hard organic cheese with added value. Together with the existing, producers develop and create new technologies and new branded products which are more original and recognizable. The goal of any technology is obtaining technologically reproducible protocol and constant uniform quality of the cheese with desired properties. In this paper some variables which influence quality of organic hard cheese were investigated. Tested samples of hard organic cheese from different production time showed consistent quality and obtained parameters followed the standards of full-fat hard cheeses. [Projekat Ministarstva nauke Republike Srbije, br. 31095]

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