Effect of processing method on bacterial community recovered from scalder and chiller water tanks in a commercial broiler processing facility.

Authors: LOCATELLI, AUDE - Department Of Energy; Rothrock, Michael; Hiett, Kelli

Submitted to: Poultry Science Association Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2016
Publication Date: 7/20/2016
Citation: Locatelli, A., Rothrock Jr, M.J., Hiett, K.L. 2016. Effect of processing method on bacterial community recovered from scalder and chiller water tanks in a commercial broiler processing facility. Poultry Science Association Meeting Abstract. New Orleans, Louisiana, July 11-14, 2016. P. 516.

Interpretive Summary: In poultry processing plants, chicken carcasses were processed through a succession of steps including their immersion in scalder and chiller water tanks. Water tank microbiota may impact the microbiological quality of carcasses and the occurrence of pathogens or spoilage bacteria may lead to their contamination. This study is focused on the impact of two processing methods on the recovery of bacterial communities in scalder and chiller water. Water samples were collected in a commercial broiler processing facility from scalder and chiller tanks and were processed following two methods before DNA extraction. In the direct method, DNA extraction was performed on 1 ml of raw water directly collected from tanks. In the filtrate method, 100 ml of tank water was filtrated several times before performing the DNA extraction. The bacterial community structure of scalder and chiller tank water was characterized using 16S rRNA gene based pyrosequencing. A similar number of phyla were evidenced for chiller water processed by both methods with Proteobacteria, Firmicutes, Actinobacteria and Tenericutes representing more than 75% of the assigned phyla. For scalder water, the filtrate method allowed to recover a higher number of phyla than the direct method. Proteobacteria, Firmicutes, Tenericutes and Actinabacteria represent more than 75% of the assigned phyla recovered with the filtrate method. By contrast, with the direct method, Firmicutes represent 70% of all the assigned phyla. No pathogens were recovered with the sequencing method but spoilage bacteria were evidence in scalder and chiller water tank with both processing methods. Bacterial community recovered from scalder water tank was highly dependent of the processing method contrarily to bacterial community from chiller tank. The temperature in scalder tank reaches 60°C whereas chiller tank is at 4°C. The high temperature exerts a selective pressure on bacterial community in scalder tank that lead to the overgrowth of Firmicutes, which is a thermotolerant phylum. However, in the filtrate method, most of the bacteria remain fixed to debris and particles occurring in the collected scalder water that induce an underestimation of the proportion of Firmicutes.

Technical Abstract: In poultry processing plants, chicken carcasses were processed through a succession of steps including their immersion in scalder and chiller water tanks. Water tank microbiota may impact the microbiological quality of carcasses and the occurrence of pathogens or spoilage bacteria may lead to their contamination. This study is focused on the impact of two processing methods on the recovery of bacterial communities in scalder and chiller water. Water samples were collected in a commercial broiler processing facility from scalder and chiller tanks and were processed following two methods before DNA extraction. In the direct method, DNA extraction was performed on 1 ml of raw water directly collected from tanks. In the filtrate method, 100 ml of tank water was filtrated several times before performing the DNA extraction. The bacterial community structure of scalder and chiller tank water was characterized using 16S rRNA gene based pyrosequencing. A similar number of phyla were evidenced for chiller water processed by both methods with Proteobacteria, Firmicutes, Actinobacteria and Tenericutes representing more than 75% of the assigned phyla. For scalder water, the filtrate method allowed to recover a higher number of phyla than the direct method. Proteobacteria, Firmicutes, Tenericutes and Actinabacteria represent more than 75% of the assigned phyla recovered with the filtrate method. By contrast, with the direct method, Firmicutes represent 70% of all the assigned phyla. No pathogens were recovered with the sequencing method but spoilage bacteria were evidence in scalder and chiller water tank with both processing methods. Bacterial community recovered from scalder water tank was highly dependent of the processing method contrarily to bacterial community from chiller tank. The temperature in scalder tank reaches 60°C whereas chiller tank is at 4°C. The high temperature exerts a selective pressure on bacterial community in scalder tank that lead to the overgrowth of Firmicutes, which is a thermotolerant phylum. However, in the filtrate method, most of the bacteria remain fixed to debris and particles occurring in the collected scalder water that induce an underestimation of the proportion of Firmicutes.