Submitted to: International Journal of Food Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/11/2017
Publication Date: 12/16/2017
Citation: Huang, L., Li, C., Hwang, C. 2017. Growth and no-growth boundary of Clostridium perfringens in cooked meat: a probabilistic anaylysis. International Journal of Food Microbiology. 107:248-256.
Interpretive Summary: Clostridium perfringens is a major food safety hazard frequently associated with cooked meat and poultry products regulated by the USDA Food Safety and Inspection Service. The growth of this pathogen can produce an enterotoxin that causes food poisoning. This study was conducted to examine to effect of phosphate, lactate, and salt on the growth of this microorganism. The results showed that proper combinations of phosphate, lactate, and salt effectively inhibited the growth of C. perfringens in a solid medium and ground beef under the optimum temperature. A mathematical model was developed to predict the growth probability of this microorganism as affected by these ingredients. It can be used to formulate meat and poultry products that do not support the growth of this microorganism.
Technical Abstract: Clostridium perfringens is a major foodborne health hazard that can cause acute gastroenteritis in consumers, and is often associated with cooked meat and poultry products. Improper cooling after cooking may allow this pathogen to grow in a product, producing an enterotoxin that causes food poisoning. This study was conducted to evaluate the effect of common ingredients, including sodium tripolyphosphate (STPP), sodium lactate (NaL), and sodium chloride (NaCl), on the germination and outgrowth of C. perfringens spores in meat products. A preliminary growth/no-growth test was conducted using a three-strain cocktail of C. perfringens spores in Schaedler anaerobe broth with STPP, NaL, NaCl, sodium diacetate, and sodium nitrite. The experiments were refined and conducted in Shahidi Ferguson Perfringens (SFP) agar mixed with STPP (0-2500 ppm), NaL (0-4%), and NaCl (0-4%) in microplates. Turbidity measurements at 600 nm were compared before and after anaerobic incubation at 46 degrees C to judge growth and no-growth. The dichotomous responses were analyzed by logistic regression to develop a probability model for estimating the growth probability of C. perfringens. The probability model was validated using inoculated ground beef under optimum temperature. While prolific growth was found, no growth was observed in samples mixed with certain combinations of STPP, NaL, and NaCl. The probability of growth in beef was calculated from the probability model. If the threshold of growth was set to 0.2 for of the probability model, the accuracy of the growth and no-growth predictions was 95.7%, with 4.3% over-prediction of growth events. This study suggested that proper combinations of STPP, NaL, and NaCl could effectively control the growth of C. perfringens in cooked beef even under the optimum temperature. This study also suggested that the cooling requirements for cooked meat and poultry products can be relaxed if proper combinations of STPP, NaL, and NaCl are in meat and poultry products.