The effect of grapefruit extract and temperature abuse on growth of Clostridium perfringens from spore inocula in marinated, sous-vide chicken products

Abstract

Clostridium perfringens growth from a spore inoculum was investigated in vacuum-packaged, cook-in-bag, marinated chicken breast that included additional 1.0% NaCl. The packages were processed to an internal temperature of 71.1 °C, ice chilled and stored at various temperatures. The total C. perfringens population was determined by plating diluted samples on tryptose–sulfite–cycloserine agar followed by anaerobic incubation for 48 h at 37 °C. At 19 °C, C. perfringens levels were consistently about 2.5 log 10 CFU/g until 9.5 h regardless of the presence or absence of Citricidal®. However, storage of the unsupplemented marinated chicken samples and those with 50 or 100 ppm Citricidal® samples at 25 °C for more than 6 h resulted in rapid growth of C. perfringens, exhibiting 2–3 log 10 CFU/g increase at 7 h. Citricidal® at 200 ppm significantly ( p < 0.05) reduced the growth of C. perfringens at both 19 and 25 °C. The D-values obtained at 90 °C were significantly decreased ( p < 0.05) from 14.07 (no Citricidal®) to 9.20 min (200 ppm Citricidal®). Supplementing marinated chicken products with Citricidal® and the temperature abuses had no consistent effect on color, shear force or lipid oxidation. However, the organism may grow to unsafe levels if sous-vide products are poorly handled or temperature abused for a relatively long period. An extra degree of safety may be assured in such products by supplementation with 100 or 200 ppm Citricidal®. Industrial relevance: Since temperature abuse is a common occurrence during trasportation, distribution, storage or handling in grocery stores or by consumers, an extra degree of safety may be assured in marinated chicken products by supplementation 100–200 ppm Citricidal®. In such products, the temperature abuse should not have any consistent effect on color, shear force or lipid oxidation of products.