Medycyna Wet. 65 (10), 710-714, 2009
full text
| Bełkot Z., Pełczyńska E. |
| Influence of the chilling room environment on the bacterial contamination of slaughter chicken carcasses |
| The purpose of the research was to evaluate the chilling environment – the waters from the spin-chillers and the air from the chilling rooms – on the bacterial contamination of broiler chicken carcasses after slaughter. The research was conducted on two chilling systems for poultry used in Polish slaughterhouses: immersion and evaporative chilling. Forty samples of water from the spin-chillers underwent microbiological analysis as well as 20 samples of air from chilling rooms of both chilling systems. The following were determined from the above-mentioned materials: the total count of aerobic bacteria and coliforms, as well as the psychrotrophic and proteolytic groups. The presence of Salmonella was only evaluated in the water samples from the refrigerators (20 samples from each of the systems). A significant influence of the type of chilling system on the contamination of the water from the spin-chillers has been demonstrated on all the evaluated groups of bacteria. Water derived from the evaporative chilling system contained significantly more microflora (8.9x103 cfu/ml) in comparison to the immersion system (7.0x103 cfu/ml). The chilling system varied the percentage of particular groups of evaluated bacteria in the total microflora contamination in the water from the spin-chillers. Depending on the chilling system the percentage of the coliforms was 5 – 9% of the total count of bacteria, the percentage of psychrotrophic bacteria from 43 – 52%, proteolytic bacteria from 27 – 40%. The presence of Salmonella was confirmed in the water from the spin-chillers of both of the systems. They were isolated more frequently in the immersion system (90% of the samples were positive) than in the evaporative chilling (50%). The most frequently isolated serotype was S. Enteritidis, the presence of which was confirmed in half of all water samples under examination. The remaining serotypes (S. Agona, S. Infantis, S. Hadar and S. Cremieu) were isolated less frequently. The analysis of the microbiological contamination of the air from the chilling rooms only demonstrated significant differences between both systems in the Coli and proteolytic groups. The count of the above-mentioned bacteria in l m3 of air was lower in a chilling room of the immersion system than in an evaporative chilling. There were no differences in the total count of bacteria and in the psychrotrophic bacteria. The total contamination in l m3 of air in the immersion system amounted to 2.9x103 cfu. The count of coliforms in this system was 6.8x10 cfu/m3, which constituted 2.34% of the total count of bacteria, while in the evaporative chilling it was 2.7x102 cfu (10%). The psychrotrophic bacteria contamination constituted l.4x103 (48.27 %) in the immersion and l.6x103 (59.25%) in the evaporative chilling. Proteolytic bacteria constituted from 10% in the immersion to 33% in the evaporative chilling of the total count of bacteria. Water from the spin-chillers contained nonspecific microflora, as well as Salmonella. Contamination with nonspecific microflora was higher in water from spin-chillers from the evaporative chilling, which might have been caused by the manual eviscerating of the carcasses. On the other hand, Salmonella were confirmed more frequently in water from the immersion system. The most frequently occurring serotype was S. Enteritidis. The bacterial contamination of the air in chilling rooms of both chilling systems differed between themselves with regards to Coli and proteolytic group bacteria counts. It was lower in the chilling room of the immersion chilling. The chilling room environment has a significant impact on the bacterial contamination of broiler chicken carcasses in the final phase of their production – primarily through the water from the spin-chillers, but also as a result the air movement. |
| Key words: chickens, chilling room, air, water, bacterial contamination, Salmonella |