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Transmission pathways of foodborne viruses include contamination of food by infected food handlers, by contamination of food during the production process and by consumption of products of animal origin harbouring a zoonotic virus. Viral foodborne illnesses, which have become a significant cause of all reported foodborne illnesses in recent years and considered as an emerging risk in veterinary public health. Microbiological genomics studies discovered that Noroviruses and hepatitis A viruses were primarily associated with food-handler transmission and sewage-contaminated foods. In contrast, hepatitis E was associated with consumption of raw or undercooked meat of pig or wild animals. In order to facilitate source attribution and identify risk prevention measures, Routine harmonized surveillance of viral outbreaks, and surveillance of virus occurrence in food commodities, in combination with systematic strain typing, and joint expertise from veterinary, food, and clinical microbiologists would be recommended.

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Algae from the genus Prototheca are the only plant-like microorganisms which can cause inflammation and alterations in the mammary gland. Prototheca mastitis is usually recognized as a chronic and symptomless disease with reduced milk production and a very high somatic cell count. Molecular identification of Prototheca spp. is helpful for the differentiation of pathogenic from non-pathogenic strains which are probably milk contaminants. Genotype-specific PCR assays, based on the 18S rDNA gene sequences, have recently been developed to differentiate three genotypes of Prototheca zopfii, of which Prototheca zopfii genotype 3 was reclassified in a new species: Prototheca blaschkeae. P. zopfii genotype 2 is characterized as the main causative agent of Prototheca mastitis that leads to significant economic losses in primary milk production. The purpose of this study was to give a molecular characterization of Prototheca strains isolated in cases of subclinical and clinical mastitis, as well as to determine the influence of these pathogenic algae on the milk somatic cell count. After microbiological examination, algae from the genus Prototheca were isolated in pure cultures from 1.8% of all tested milk samples, and all 13 (100%) isolates were determined as Prototheca zopfii genotype 2 by a genotype-specific PCR. This study has provided the first molecular identification of Prototheca zopfii genotype 2 in the Republic of Serbia. In the case of subclinical Prototheca mastitis, the somatic cell count was 4,175,244 ± 1,233,685/mL of milk. A distinctly higher somatic cell count (P<0.05) was found in the quarters infected by Prototheca zopfii genotype 2 than in the quarters infected by Staphylococcus aureus, which is the most common mastitis causative agent worldwide. The results from this study support previous observations that P. zopfii genotype 2 is the main causative agent of Prototheca mastitis which leads to a significant increase in the somatic cell count in the milk.

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The aim of this study was to assess the expression of a toxic shock syndrome toxin-1 (TSST-1) gene of Staphylococcus aureus in different types of milk, depending on inadequate temperature and storage conditions. Pasteurized and UHT milk were inoculated with monotoxic TSST-1 strain of S. aureus and growth kinetics was determined by the drop plate method using Baird-Parker agar medium in accordance with EN ISO 6888-1. The patterns of gene regulation were detected by quantitative reverse transcriptase PCR. Relative quantification method for statistical significance testing was used to detect significant gene expression responses. The results of experiments showed the dependence of the growth rate and consequent up-regulation of TSST-1 encoding gene on storage time-temperature and type of milk. In contaminated pasteurized and UHT milk kept at both 15 °C and 22 °C S. aureus significantly increased its virulent potential over time. This effect was a bit more emphasized in UHT milk serving as a "proof of concept". Possible explanation could be a presence of lactic acid bacteria in pasteurized milk which is known to have down-regulatory effect on TSST-1 gene. Maintenance of the milk storage temperature below 8 °C and employment of microbiological control measures in hygienic practices, from milk producer through retailer and on to the consumer is of utmost importance to decrease risk of non-emetic staphylococcal poisoning.

Broiler meat quality depends on the interaction of several factors, including genotype, slaughter age/body weight, pre-slaughter handling, and slaughter method. The aim of this study was to determine the eff ect of slaughter weight on meat yield and quality of broilers. The material consisted of 42 broilers, classifi ed into three groups: lighter (<2500 g), medium (2500-3000 g) and heavier (>3000 g). The following meat yield parameters were measured: cold carcass weight, breast weight before and after deboning, breast skin and bone weights, thigh weight before and after deboning, thigh skin and bone weights, drumstick weight before and after deboning, and drumstick skin and bone weights. Meat pH (M. pectoralis major) and instrumental colour (breast and drumstick) were measured 24 h post-mortem. Meat quality classes (pale, soft and exudative and normal meat) were determined based on breast muscle L* value. Heavier broilers had higher (P<0.05) cold carcass weight, breast, thigh and drumstick weights both before and after deboning compared to medium and lighter broilers. In contrast, meat quality traits were not signifi cantly (P>0.05) aff ected by slaughter weight. In conclusion, production of heavy broilers had a benefi cial eff ect on meat quantity, while the eff ect of slaughter weight on meat quality was negligible.

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