Use of Organic Acids for the Control of Clostridium perfringens in Cooked Vacuum-Packaged Restructured Roast Beef during an Alternative Cooling Procedure

Abstract

This study was conducted to determine how well Clostridium perfringens spores germinate and grow in restructured roast beef treated with different commercial organic salts during an alternative chilling procedure. The meat was prepared according to an industrial recipe (10% water, 1.5% sodium chloride, and 0.5% sodium triphosphate). The base meat was treated with sodium citrate at 2 or 4.8% (wt/wt), buffered to a pH of 5.6, 5.0, or 4.4 (six treatments); a 60% (wt/wt) solution of sodium lactate at 2 or 4.8% (wt/wt); sodium acetate at 0.25% (wt/wt); or sodium diacetate at 0.25% (wt/wt). Untreated meat was used as a control. Meat samples were inoculated with a three-strain cocktail of C. perfringens spores (strains ATCC 10388, NCTC 8238, and NCTC 8239). Meat was vacuum packaged in bags and cooked in a stirred water bath to an internal temperature of 75°C for 20 min, and then the bags were cooled from 54.4 to 4.4°C within 18 h. Samples were taken after inoculation, after cooking, and after chilling. Spore and vegetative cell counts were obtained after incubation at 37°C for 8 to 10 h in Fung's Double Tubes containing tryptose sulfite agar without egg yolk enrichment. Cooking was not sufficient to eliminate C. perfringens spores. Over the 18-h cooling period, sodium citrate, sodium lactate, and sodium diacetate reduced the growth of C. perfringens to <1 log unit, a growth level that meets U.S. Department of Agriculture performance standards. The use of sodium citrate or sodium lactate at a concentration of ≥2% (wt/wt) inhibited C. perfringens growth over the 18-h cooling period.