Submitted to: International Journal of Food Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/20/2004
Publication Date: 6/1/2004
Citation: Juneja, V.K., Thippareddi, H. 2004. Inhibitory effects of organic acid salts on growth of clostridium perfringens from spore inocula during chilling of marinated ground turkey breast. International Journal of Food Microbiology. 93:155-163.
Interpretive Summary: One of the most common types of food poisoning in the United States is caused by the bacterium, Clostridium perfringens. Illnesses have been traditionally associated with inadequate cooling practices in retail food service operations. Thus, there was a need to determine the cooling time and temperature for cooked meat products to remain pathogen-free and provide vital data for performing risk assessment on cooked meat. We determined that cooling times for marinated ground turkey breast products after heat processing can be extended to 21 h by incorporation of the antimicrobial ingredients, sodium lactate, sodium acetate, buffered sodium citrate, or buffered sodium citrate supplemented with sodium diacetate, at more than or equal to1.0% in the formulation to reduce the potential risk of C. perfringens germination and outgrowth. These findings will be of immediate use to the retail food service operations and regulatory agencies to ensure the safety of the cooked foods.
Technical Abstract: Inhibition of Clostridium perfringens germination and outgrowth by salts of organic acids such as sodium lactate, sodium acetate, buffered sodium citrate and buffered sodium citrate supplemented with sodium diacetate was evaluated during continuous chilling of ground turkey. Turkey breast meat was injected with a brine containing NaCl, potato starch and potassium tetra pyrophosphate to yield final in-product concentrations of 0.85, 0.25 and 0.20%, respectively. The meat was ground, mixed with either sodium lactate (1, 2, 3 or 4%), sodium acetate (1 or 2%), buffered sodium citrate (IonalTM, 1%) or buffered sodium citrate supplemented with sodium diacetate (Ional PlusTM, 1%), in addition to a control that did not contain added antimicrobials. Each product was mixed with a three-strain C. perfringens spore cocktail to obtain final spore concentrations of ca. 2.8 log10 spores/g. Inoculated products (10 g) were packaged into cook-in-bags (2 in. x 3in.), vacuum sealed, cooked at 60°C for 1 h, and subsequently chilled from 54.4° C to 7.2°C in 15, 18 and 21 h following exponential chilling rates. Products were sampled immediately after cooking and then after chilling. Chilling of cooked turkey following 15, 18 and 21 h chill rates resulted in germination and outgrowth of C. perfringens spores to 6.6, 7.58 and 7.95 log10 CFU/g populations, respectively, from initial spore populations of ca. 2.80 log10 CFU/g. Incorporation of sodium lactate (1%), sodium acetate (1%), Ional or Ional Plus (1%) substantially inhibited germination and outgrowth of C. perfringens spores compared to controls. Final C. perfringens total populations of 3.12, 3.10, 2.38 and 2.92, respectively, were observed following a 15 h exponential chill rate. Similar inhibitory effects were observed for 18 and 21 chill rates with the antimicrobials at 1% concentrations. While sodium lactate and sodium acetate concentrations of 1% were sufficient to control C. perfringens germination and outgrowth (< 1.0 log10 CFU/g growth) following 15 h chill rates, higher concentrations were required for 18 and 21 h chill rates. Ional at 1% concentration was effective in inhibiting germination and outgrowth to < 1.0 log10 CFU/g of C. perfringens for all three chill rates (15, 18, and 21 h) tested. Use of sodium salts of organic acids in formulation of ready-to-eat meat products can reduce the risk of C. perfringens spore germination and outgrowth during chilling.