Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/25/2011
Publication Date: 10/1/2011
Citation: Gunther, N.W., He, Y., Fratamico, P.M. 2011. Effects of polyphosphate additives on the pH of processed chicken exudates and the survival of Campylobacter. Journal of Food Protection. 74:1735-1740.
Interpretive Summary: The use of polyphosphate containing marinades on chicken products has been shown to increase the survival of the disease causing bacteria known as Campylobacter even under conditions of cold storage. This is a serious issue since Campylobacter are responsible for the largest amount of bacterial foodborne gastrointestinal infections annually in the developed world. Additionally, the most common manner for introducing Campylobacter to humans is through improperly prepared poultry. This manuscript describes how the polyphosphate component of the marinades decreases the acidity (increases the pH reading) of the food environment in which the Campylobacter are found and that this pH change is responsible for the increased survival of this dangerous pathogenic bacterium. The research examined several different polyphosphates currently being used by the poultry industry and shows how some of the polyphosphate have smaller effects on the environmental pH and therefore Campylobacter survival compared to other polyphosphates. It is suggested by this work that poultry processing companies should only use polyphosphates that minimally affect the pH of the chicken environment and subsequent Campylobacter survival. This would help decrease the risk that Campylobacter currently presents to the food supply and the consumer.
Technical Abstract: Campylobacter spp. are nutritionally fastidious organisms that are sensitive to normal atmospheric oxygen levels and lack homologues of common cold shock genes. At first glance these bacteria seem ill equipped to persist within food processing and storage conditions; however, they survive in numbers sufficient to cause the largest number of foodborne bacterial disease annually. A mechanism proposed to play a role in Campylobacter persistence is the addition of polyphosphate-containing marinades during poultry processing. Campylobacter jejuni and Campylobacter coli strains incubated in chicken exudate treated with a marinade demonstrated considerable survival advantages (1 - 4 log CFU/ml) over the same strains incubated in untreated chicken exudate. Polyphosphates, which constitute a large portion of the commercial poultry marinades, were shown to account for a majority of the observed influence of the marinades on Campylobacter survival. When six different food grade polyphosphates (disodium pyrophosphate, tetrasodium pyrophosphate, pentasodium triphosphate, sodium polyphosphate, monosodium phosphate, trisodium phosphate) were utilized to compare the survival of Campylobacter strains in chicken exudate, significant differences were observed with regards to Campylobacter survival between the different polyphosphates. It was then determined that the addition of polyphosphates to chicken exudate increased the pH of the exudate with the more sodiated polyphosphates increasing the pH to a greater degree than the less sodiated polyphosphates. It was confirmed that the change in pH mediated by polyphosphates is “the mode of action” responsible for the increased Campylobacter survival.