Neđeljko Karabasil

Environmental prevalence and persistence of Listeria monocytogenes in cold-smoked trout processing plants.

The presence of Listeria monocytogenes on the surfaces of equipment and worker’s hands during different production stages, as well as on fish skin and meat during processing and storage of cold-smoked trout, was investigated. Listeria monocytogenes was recovered from 10 (6.06%) of a total 165 cotton-swabbed samples collected from the surfaces of equipment and worker’s hands at two separate processing facilities. Of 105 samples collected from fish skin and meat during various production steps in both processing plants, 14 (13.33%) were confirmed culture-positive for L. monocytogenes, with recovery being most frequently in samples collected in the area before vacuum packaging. Recovery rates at two different Serbian processing plants did not differ (p<0.05), but suggested that different L. monocytogenes serotypes appeared to be resident within each processing plant and may have contributed to the final product contamination. From all smoked trout samples collected during 7, 14, 21 and 28 days of storage at 4oC only two were culture-positive for L. monocytogenes serotype 1/2a and both of these were collected on the 7th day of storage. Conversely, 4, 3 and 1 sample(s) were contaminated with L. monocytogenes serotypes 1/2a and 1/2b after 7, 14 and 21 days storage at 10oC. Listeria monocytogenes was not recovered from smoked trout stored 28 days at 10oC. Results emphasize the importance of adhering to strict hygienic and quality control standards throughout the processing environment.

Detection of icaA and icaD genes of Staphylococcus aureus isolated in cases of bovine mastitis in the Republic of Serbia

Abstract Staphylococcus aureus (S. aureus) is the most common agent of contagious mastitis that causes serious health and economic problems. The ability to form biofilms is an important virulence factor of S. aureus for the establishment of persistent infections. This study is aimed to investigate the presence of icaA and icaD, two genes of importance for the biofilm formation in S. aureus bovine mastitis isolates. In order to isolate and identify S. aureus, 1555 milk samples were collected from 401 cows, located in different regions of the Republic of Serbia. Using the conventional microbiological methods 100 isolates were characterized as coagulase-positive staphylococci. After primary biochemical identification, the species confirmation of 44 S. aureus isolates was done using MALDI-TOF Mass Spectrometry and PCR technique, targeting the S. aureus-specific nuc gene. Among all investigated S. aureus isolates 25.0% harbored both icaA gene and icaD genes. The presence of icaD gene alone was confirmed in 40.9% of cases totaling icaD positive isolates to 65.9%. The remaining 34.1% of S. aureus isolates were negative for the presence of both genes. The results of the present study indicate the existence of potential biofilm-producer strains in different regions of the Republic of Serbia, both under intensive and semi-extensive cows breeding.

VIRUSI - AKTUELNI ALIMENTARNI PATOGENI

Virusne infekcije prenosive hranom sve se češće javljaju u mnogim delovima sveta. Procena realne zastupljenosti virusnih bolesti koje se prenose putem hrane otežana je usled neprijavljivanja infekcija i nepostojanja sveobuhvatnih sistema za nadzor. Nekoliko grupa virusa može izazvati oboljenje ljudi nakon konzumacije kontaminirane hrane. Na osnovu simptoma infekcije, mogu se razvrstati na: one koji izazivaju gastroenteritis (Norovirus-NoV, Rotavirus-HRV, Astrovirusi, Adenovirusi i Sapovirusi), zatim one koji iz creva migriraju u jetru i uzokuju hepatitis (Hepatitis A-HAV i Hepatitis E-HEV) i virusi koji se umnožavaju u crevima, a do bolesti dovode jedino ako migriraju u druge organe, na primer u centralni nervni sistem (Enterovirusi). Trenutno najznačajniji alimentarni patogeni su Norovirus (NoV) i Hepatitis A virus (HAV). Svi pomenuti virusi se šire fekalnom kontaminacijom, ali i direktnim kontaktom ili transmisijom virusnih čestica putem aerosola. Hrana može biti primarno kontaminirana virusom ili naknadno tokom čitavog lanca hrane. Virusi se u njoj ne razmnožavaju, ali mogu opstati duži vremenski period ili u samoj hrani, ili kao infektivne čestice u okruženju. Danas dostupna Real Time RT-PCR metoda je glavna tehnika detekcije virusa u hrani, vodi i drugim uzorcima. Kao preventivne i kontrolne mere u sprečavanju virusnih infekcija preko hrane preporučiju se: podizanje svesti rukovaoca hranom standardizacija metoda za detekciju virusa u hrani razvoj laboratorijski baziranog nadzora za otkrivanje izvora epidemije u ranoj fazi, kao i naglašavanje značaja razmatranja virusa u integrisanim sistemima za bezbednost hrane (GHP, GMP, HACCP). Osim toga, naglašava se i značaj uvođenja monitoringa virusa u hrani, u cilju poboljšanja zaštite javnog zdravlja.

The interactive effects of transportation and lairage time on welfare indicators, carcass and meat quality traits in slaughter pigs

This study assessed the effects of transportation and lairage time and their interaction on welfare, carcass and meat quality traits in slaughter pigs under commercial conditions. The study was conducted on 120 pigs with a live weight of approximately 115 kg and about six months old. A complete blood picture was measured in pigs to assess pre-slaughter stress. Also, nine different carcass quality parameters including live weight, hot and cold carcass weights, cooling loss, dressing percentage, backfat thickness, meatiness and skin lesions score were measured. The pH and temperature measurements were performed 45 minutes post-mortem. The results showed that short transportation time and slaughtering without lairaging and long transportation time and overnight lairaging negatively influenced the hematological parameters, which meant that the animal welfare was seriously compromised under these pre-slaughter conditions. Long transportation time and overnight lairaging reduced live and carcass weights and increased the incidence of skin lesions on the carcass and DFD pork. In addition, short transportation time and slaughtering without lairaging caused a significant deterioration in pork quality. It can be concluded that, from the standpoint of animal welfare, carcass and meat quality, the above-mentioned pre-slaughter conditions are not recommended to the farmers and/or pork producers.

Perspectives in production of functional meat products

The meat industry has met new challenges since the World Health Organization classified processed meat in carcinogenic Group 1. In relation to this, the functional food concept in meat processing has gained importance, especially in reducing carcinogenic N-nitroso compounds and polycyclic aromatic hydrocarbons (PAHs) as an additional imperative, apart from the usual fat and salt reduction and product enrichment with functional ingredients. PAH reduction relies on control of the smoking process, but there is also a possibility they could be degraded by means of probiotic microorganisms or spices. The reduction of N-nitroso compounds could be provided by lowering the amount of added nitrite/nitrate, using substitutes for these chemicals, and/or by preventing conditions for the creation of N-nitroso compounds. Nevertheless, fat and salt reductions still remain topical, and rely mostly on the use of functional ingredients as their substitutes.

Some risk factors that affect contamination of mussels (Mytilus galloprovincialis) from the Bay of Kotor, Montenegro

Pollution and contamination of the Bay of Kotor ecosystem arise from both anthropogenic sources and natural weathering. In recent decades, a need has arisen for regular control of marine organisms, which are used in human nutrition, because the entire bay is constantly and increasingly exposed to negative anthropogenic impact. Molluscs, including mussels (Mytilus galloprovincialis), can be involved in foodborne disease. They are filter feeding organisms, able to retain and concentrate in their bodies the bacteria, parasites, viruses and biotoxins of marine algae present in their external environment. A structured field study was undertaken in the Bay of Kotor, Montenegro, in order to investigate plausible influence of environmental factors, like rainfall and temperature, on the variability of Escherichia coli and norovirus (NoV). This study focuses on human-derived pathogens that are abundant in sewagerelated sources. We proved the negative correlation between outside temperature and the number of E.coli and the presents of Norovirus in Bay of Kotor mussel. We used this data from the sampling site to discuss options to better manage the risk of contamination of shellfish. From the aspect of food safety, an upgrade of monitoring plans in the future could lead to obtaining safer products.

Assessment of welfare conditions during stunning of pigs with respect to the day of the week.

Proper stunning is important in order to ensure animal welfare and to improve meat quality. The conditions in which the stunning is performed and the result of procedure may vary in practice due to numerous factors. The aim of this study was to examine the effectiveness of the stunning procedure with respect to the day of the week. The experiment was conducted on 100 pigs of different genetic origin and of different age and live weight during 5 working days (20 pigs per day). Stunning procedure was assessed through the following parameters: placing of electrodes at the proper position on the head; application of energized electrodes; voltage, amperage and frequency of the current; duration of current application and interval from stunning to bleeding; presence of tonic, clonic convulsions, as well as rhythmic breathing and re-stunning. In this study, improper electrode placement was observed in 40-70% of pigs, application of energized electrodes in 5-45% of pigs, duration of current application from 6,90 to 17,55 seconds, and the interval from stunning to bleeding from 48,62 to 91,25 seconds, the presence of tonic and clonic convulsions, and rhythmic breathing in 65-85%, 45-75% and 10- 75% of pigs. The stunning procedure was repeated in 5-15% of pigs. In addition, the deterioration of most of the parameters at the end of the week was observed. These results suggest unsuccessful stunning of pigs as a consequence of insufficient staff training, and their fatigue at the end of the week. .