Submitted to: Journal of Food Safety
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/5/2003
Publication Date: 5/5/2003
Citation: SOMMERS, C.H., FAN, X., NIEMIRA, B.A., SOKORAI, K.J. RADIATION (GAMMA) RESISTANCE AND POST-IRRADIATION GROWTH OF LISTERIA MONOCTYTOGENES SUSPENDED IN BEEF BOLOGNA THAT CONTAINED SODIUM DIACETATE AND POTASSIUM LACTATE. JOURNAL OF FOOD SAFETY. 2003. V. 66. P. 2051-2056. Interpretive Summary: Listeria monocytogenes, a food-borne pathogen, is a common contaminant on ready-to-eat (RTE) meat products such as bologna. Ionizing radiation can eliminate L. monocytogenes from RTE meats. Sodium diacetate (SDA) and potassium lactate mixtures are additives in RTE meat products and can slow the growth of L. monocytogenes. The effect of ionizing radiation, in combination with SDA/PL mixtures, on the survival of L. monocytogenes was determined. SDA/PL increased the radiation sensitivity of L. monocytogenes in bologna and prevented the growth of the microorganism during long-term refrigerated storage. The effect of ionizing radiation and SDA/PL on quality factors including lipid oxidation and color was minimal. The meat processing industry will benefit from the more efficient methodology for elimination of L. monocytogenes and consumers will benefit from a safer RTE meat product.
Technical Abstract: Listeria monocytogenes (Lm), a psychrotrophic food-borne pathogen, is a frequent post-process contaminant on ready-to-eat meat (RTE) products including bologna. Ionizing radiation can eliminate Lm from ready-to-eat meats. Sodium diacetate (SDA) and potassium lactate (PL) mixtures inhibit the growth of Lm when incorporated into fine emulsion sausages. The radiation resistance of Lm, and its ability to proliferate during long-term refrigerated storage (9 degrees C), when inoculated into beef bologna that contained no SDA/PL, 0.07 percent SDA/1 percent PL, and 0.15 percent SDA/2 percent PL, was determined. The D-10 value, the radiation dose required to eliminate 90 percent of viable Lm, was 0.56 kGy on 0 percent SDA/PL bologna, 0.53 kGy on 0.07 percent SDA/1 percent PL bologna, and 0.46 kGy on 0.15 percent SDA/2 percent PL bologna. Lm was able to proliferate on 0 percent SDA/PL bologna during refrigerated storage, but onset of proliferation was delayed by the addition of the SDA/PL mixtures. An ionizing radiation dose of 3.0 kGy prevented proliferation of Lm and background microflora in 0.07 percent SDA/1 percent PL and 0.15 percent SDA/2 percent PL bologna during eight weeks storage at 9 degrees C. Little effect on lipid oxidation and color of the control and SDA/PL containing bologna was observed when irradiated to either 1.5 or 3.0 kGy.