The aim of this study was to determine the effects of different temperatures and storage time on Staphylococcus aureus growth, sea gene expression, and synthesis of staphylococcal enterotoxin A (SEA) in the pasteurized and UHT-pasteurized milk. Pasteurized and UHT-pasteurized milk were inoculated with 3.98 log ₁₀ CFU/mL of S. aureus (ATCC 13565). Inoculated milk samples were stored at 8°C, 15°C, and 22°C for 24, 48, and 72 h, respectively. SEA synthesis was detected with a fully automated miniVIDAS instrument using the Enzyme-Linked Fluorescent Assay (ELFA) technology. The patterns of gene regulation were detected by quantitative reverse transcriptase PCR. The 2 ^−ΔΔCT method has been used as a relative quantification strategy for gene expression responses data analysis. The results indicated that growth rate, sea gene expression, and SEA synthesis were influenced by type of milk, storage time, and temperature. Incubation of milk at different temperatures (15°C and 22°C) and times was used to simulate inadequate transport and storage conditions. Storage of pasteurized milk at 22°C for 24 h significantly upregulated the expression of sea gene compared with milk stored at 8°C, which coincides with the achieved S. aureus number of 10 ⁵ CFU/mL and detected amount of SEA. In addition, storage of UHT-pasteurized milk at 22°C for 24 h and at 15°C for 48 h significantly upregulated the sea gene expression compared with milk stored at 8°C, which coincides with the detected amount of SEA and the dynamics of S. aureus number change. It can, therefore, be concluded that implementing good hygiene practices to avoid pre- and post-heat treatment milk contamination and maintaining the cold chain at temperature <8°C throughout the entire dairy production chain are of paramount importance to decrease the risk of staphylococcal food poisoning.

This study aimed to describe a new broiler meat quality class—red, soft, and exudative (RSE) meat—and to propose novel classification criteria. Two-step cluster analysis assigned 132 broilers into five meat quality classes using ultimate pH, drip loss, and L* values: pale, soft, and exudative (PSE); pale, firm, and nonexudative (PFN); RSE; red, firm, and nonexudative (RFN); and dark, firm, and dry (DFD) meat. PSE meat showed the lowest plasma superoxide dismutase activity, highest malondialdehyde activity, greater live and carcass weights, higher breast and leg yields, the lowest initial and ultimate pH, highest initial temperature, the lightest colour (the highest L* and b* values, and the lowest a* value), and the greatest drip, thawing, and cooking losses. RFN meat had the highest superoxide dismutase activity, lowest malondialdehyde activity, and remained within the optimal range for ultimate pH, drip loss, and L* value, generally occupying a midpoint between PSE and DFD meat. RSE meat shared the poor water-holding capacity of PSE but differed by showing a colour similar to RFN and an optimal ultimate pH. PFN meat had firmness comparable to RFN, with appropriate water-holding capacity and optimal ultimate pH, but an undesirably pale colour resembling PSE. DFD meat displayed the highest initial and ultimate pH, lowest drip, thawing, and cooking losses, darkest colour (the lowest L* value), and lowest protein content. This study provides the first evidence of RSE meat in broilers and proposes a classification system based on ultimate pH, drip loss, and L* values to distinguish five quality classes. Further studies are required to validate these findings and develop preventive strategies.

The antibacterial activity of cinnamaldehyde was evaluated against S. aureus experimentally inoculated (10³ CFU/mL) in UHT-pasteurized milk, which was treated with different concentrations of the cinnamaldehyde (0.1% and 0.05%) and stored at 4 °C for 12 days. The MIC of cinnamaldehyde was 160 μg/ml. During the storage period, S. aureus counts in milk were reduced by 0.35-2.77 log CFU/mL. Significantly greater decreases were observed when cinnamaldehyde was added, regardless of the concentration used, compared with the control. A triangle test showed that panellists could detect the difference between milks with different concentrations of cinnamaldehyde (P<0.01). These results suggest that by adding 0.05% cinnamaldehyde to milk, the safety of the milk can be increased and a pleasant, desirable flavour can be obtained.

DoiFil - Repository of Digital Object Identifiers (DOIs) Issued by Faculty of Philology, University of Belgrade

This paper will describe the implementation of good hygiene practices in a milk processing plant during the production of yogurt and steamed mozzarella cheese to reduce the risk of foodborne diseases, ensuring that milk and dairy products are safe and suitable for consumption. Milk, being highly perishable, is particularly susceptible to contamination and the growth of microorganisms if proper hygiene practices are not followed during its production and processing. The effectiveness of pasteurization is crucial in eliminating harmful microorganisms, but it should be viewed as only one aspect of a broader food safety system. Milk processing is a highly regulated and complex chain that starts from raw materials at the farm level and extends all the way to the finished product.

As one of the oldest food products, cheese takes an important place in the diet due to its nutritional value. In Serbia, cheeses are produced industrially, but a significant proportion is also produced in small-scale plants and individual artisanal households. Salt contributes to the salty taste and has an antimicrobial effect, but high salt intake can have negative effects on human health. The aim was to determine the salt content in cheeses available at Belgrade’s green markets and to assess safety regarding the presence of pathogens important for human health: Listeria monocytogenes, Salmonella spp. and coagulase-positive staphylococci. A total of 100 cheese samples traditionally produced in individual artisanal households were studied. The obtained results showed that NaCl content ranged from < 0.1 % to 2.5 % in raw milk cheeses and < 0.1 % to 3.7 % in heat-processed milk cheeses. L. monocytogenes and Salmonella spp. were not detected in the examined cheeses. Coagulase-positive staphylococci were detected in 26 (26 %) of the cheeses, at counts ranging from 2 log CFU·g-1 to 5.60 log CFU·g-1. It can be concluded that NaCl content in Serbian soft cheeses was lower than recommended by the WHO, but it was favourable for growth of coagulase-positive staphylococci.