Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/18/2005
Publication Date: 1/1/2006
Citation: Smith, D.P., Berrang, M.E. 2006. Prevalence and numbers of bacteria in broiler chicken crop and gizzard contents. Poultry Science. 85(1):144-147.
Interpretive Summary: Undigested feed and other materials ingested by broilers prior to slaughter (ingesta) have been suggested as a contaminant source for processed chicken carcasses. The USDA Food Safety Inspection Service recognizes ingesta as a potential hazard, but has recently deemphasized its importance due to cost impact on the poultry industry and other issues. This study was designed to determine if ingesta was a substantial source of contamination on carcasses. The crop and gizzard of broiler chickens, the two organs most likely to contain ingesta, were sampled from chickens to recover and weigh the ingesta, then determine the microbiological profile of the material. Bacteria, including general groups and a specific pathogen (Campylobacter) were found in the contents of both organs. Crop contents had higher counts, but there was not much material present that could contaminate carcasses. More contents were recovered from the gizzard, but numbers of bacteria were lower, and Campylobacter was absent in 60% of the samples. A theoretical calculation showed that even if all the contents from the crop and gizzard were to contaminate a carcass, it would not substantially change the bacterial counts on the carcass. Therefore it does not appear that, under normal conditions, ingesta is a major threat to the contamination and food safety of broiler chicken carcasses.
Technical Abstract: Crops or gizzards in broiler carcasses are frequently damaged during processing. The contents from either organ, defined by the USDA FSIS as ingesta, may contaminate the carcass. Previous research has shown crop contents are a source of Salmonella contamination on processed carcasses, although less information is available on gizzard contents. The purpose of this study was to determine the prevalence and numbers of total aerobic bacteria, coliforms, E. coli, and Campylobacter in ingesta collected from the crop and gizzard. In each of three replicate trials, 10 uneviscerated broiler carcasses were obtained from a processor at the shackle transfer point just prior to evisceration. Liquid crop contents and solid gizzard contents were aseptically collected from each carcass and quantitatively cultured. Total aerobic bacteria, coliforms, E. coli, and Campylobacter were determined for contents from both organs. Crop contents (log CFU/ml), compared to gizzard contents (log CFU/g), contained significantly (P<0.05) higher numbers of total aerobic bacteria (5.6 vs. 2.9), coliforms (4.2 vs. 2.3), E. coli (3.9 vs. 2.2), and Campylobacter (4.6 vs. 2.2). E. coli prevalence was higher in crop samples (28/29) than gizzard samples (19/30). Campylobacter prevalence was also higher for crop vs. gizzard samples (29/29 vs. 12/30). An average of 2.4 g of crop contents and 8.4 g gizzard contents were recovered. Crop contents contain more bacteria than gizzard contents, as well as a higher incidence of E. coli and Campylobacter contamination. However, due to the numbers of bacteria and amount of material in the crop and gizzard, it is unlikely that ingesta contamination would increase the overall bacterial count of pre-chill broiler carcasses.