Food Protection Trends - September/October 2016 - 355

Table 4. pH of inoculated sausage and brine, and pH, aw, and salt concentration of negative control sausages throughout 28 days of storage LAB Storage Time (hours) 0 2 4 6 12 24 48 72 168 336 504 672 Yeast + Mold pH pH Brine Sausage pH Sausage pH Brine Negative Control pH Sausage pH Brine 2.61c 3.08bc 3.17abc 3.64ab 6.54ab 6.80a 6.54ab 6.32ab 6.23ab 5.81b 4.59c 4.26c 4.13c 4.26c 3.89c 2.72d 3.40abcd 3.26bcd 2.98cd 3.12bcd 3.26bcd 3.33bcd 3.61abc 3.93ab 4.20a 3.95ab 6.52a 6.62a 6.54a 6.55a 6.33a 6.08a 4.67b 4.21b 4.05b 4.11b 3.92b 2.72e 3.03de 3.12cde 3.23cde 3.03de 3.19cde 3.30bcde 3.39abcd 3.76abc 3.93ab 3.91ab 6.44a 6.26a 6.09a 3.97b 3.88b 3.88c 3.89ab 3.96b 4.00a 3.96b aw 3.82ab 0.97a 0.96a 0.97a 0.96a 0.95a 3.94a 0.96a - Salt Salt Concentration - Concentration - Sausage Brine a 2.26 4.86a a 2.19 4.64a 2.29a 4.71a a 2.69 4.73a 2.53a 4.44a 2.80a 4.30a Different letters represent significant difference in values within each column (P = 0.2062). All numerical values are the mean of (n = 3) 1 sausage/replication). a-e hypothesis that temperature impacts the ability of acids and preservatives to produce antimicrobial effects in food systems. Among the three groups of spoilage microorganisms utilized in the current study, select LAB cultures demonstrated the greatest acid tolerance, exhibiting higher populations throughout the study, when compared to select yeast or mold cultures (Table 3). The addition of salt, decrease in pH, the reduction of aw, and brine injection have caused shifts in the microflora of meat products to favor LAB (4, 10). The pickling process in this study may have created an environment which initially allowed LAB populations to persist longer than both the yeast or mold cultures. Noonpakdee et al. demonstrated that LAB have the potential to become more acid-tolerant if viable cells are exposed to sub-lethal acidic conditions for an extended period of time (19). In other studies, synergistic effects between decreased pH and increased sodium chloride concentrations also resulted in decreased yeast populations (3, 34). The 5% salt and 5% acetic acid brine solution utilized in this study achieved significant reductions in yeast populations that suggest a synergistic inhibitory effect of the brine. Other studies have found that yeast populations can be decreased by the addition of as little as 1% acetic acid, and yeast growth can be entirely inhibited at concentrations of 3.5 to 4% (35). Although molds can survive at various pH levels and salt concentrations (2-3% wt/wt; 16, 21), these factors did not appear to aid in the survival or growth of select molds (P. nalgiovense, C. cladosporioides) used in this study. While previous studies have noted the abilities of LAB, yeasts, and molds to adapt, resist, and break down food preservatives, the acidity of the brine solution used in this study was likely too high for the microorganisms to adapt to or counteract its lethality (9, 18, 19, 20, 27). To our knowledge, this is the first study that has measured the survival of spoilage microorganisms in a pickled meat product. Furthermore, this study demonstrated the ability of a cold fill pickling process to inhibit the growth and survival of LAB, yeast, and mold on a pre-cooked RTE pickled sausage product. The use of industry standard sausage production parameters (casing type, diameter, formulation) and spoilage microorganisms associated with meat products, also greatly enhance the applicability of this study. The findings of this study will be most useful as Hazard Analysis Critical Control Point (HACCP) validation for manufacturers of pickled sausage that utilize a cold fill process. Future work by these authors will examine the efficacy of the cold fill pickling process on sausages inoculated with relevant strains of Salmonella spp., Listeria monocytogenes, and Staphylococcus aureus. September/October Food Protection Trends 355

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