Bacterial growth in refrigerated, vacuum-packed luncheon meats

Abstract

The shelf life of vacuum-packed luncheon meats during refrigerated storage was not related to "total" counts since the only organisms that multiplied in this environment were lactic acid bacteria, which formed only a small proportion of the initial population.Bacterial growth curves obtained from several Canadian products were remarkably similar, but the spoilage patterns differed. For example, wiener spoilage was a function of bacterial growth while bologna spoiled from the accumulation of bacterial end products. After 15 weeks at 5 °C, the meats contained 0.6 to 0.8% lactic acid and the pH of comminuted meats dropped below 5.0. Cooked ham contained much less carbohydrate than comminuted meats, and the pH remained above 6.0. Under these conditions, ham is susceptible to putrefaction although this was not observed during this study.It was found that cooking can eliminate all lactic acid bacteria present in the raw meats but the products become recontaminated during slicing and packaging. The cleaning and sanitizing procedure used by the Company that cooperated in this study was efficient, but it was recommended that the packaging room be cleaned more often, and that a selective medium for lactic acid bacteria be used in sanitation surveys.