Mathematical Model for Predicting the Growth Probability of Staphylococcus aureus in Combinations of NaCl and NaNO₂under Aerobic or Evacuated Storage Conditions

Abstract

The objective of this study was to describe the growth patterns of Staphylococcus aureus in combinations of NaCl and NaNO 2, using a probabilistic model. A mixture of S. aureus strains (NCCP10826, ATCC13565, ATCC14458, ATCC23235, and ATCC27664) was inoculated into nutrient broth plus NaCl (0, 0.25, 0.5, 0.75, 1, 1.25, 1.5, and 1.75%) and NaNO 0,15,30, 45, 60, 75, 90, 105, and 120 ppm). The samples were then incubated at 4, 7, 10, 12 and 15°C for up to 60 d under aerobic or vacuum conditions. Growth responses [growth (1) or no growth (0)] were then determined every 24 h by turbidity, and analyzed to select significant parameters (p<0.05) by a stepwise selection method, resulting in a probabilistic model. The developed models were then validated with observed growth responses. S. aureus growth was observed only under aerobic storage at 10-15°C. At 10-15°C, NaCl and NaNO 2 did not inhibit S. aureus growth at less than 1.25% NaCl. Concentration dependency was observed for NaCl at more than 1.25%, but not for NaNO 2 . The concordance percentage between observed and predicted growth data was approximately 93.86%. This result indicates that S. aureus growth can be inhibited in vacuum packaging and even aerobic storage below 10°C. Furthermore, NaNO 2 does not effectively inhibit S. aureus growth.

Mathematical Models to Describe the Kinetic Behavior of Staphylococcus aureus in Jerky

“…This result suggests that S. aureus can survive in beef jerky even if A W is less than 0.850. Additionally, Lee et al (2016) indicated that S. aureus did not grow under vacuum conditions. Hence, we developed predictive models using the seasoned beef jerky products as a model product under aerobic conditions to predict the most severe case of S. aureus growth.…”

Selection and Characterization of Staphylococcus hominis subsp. hominis WiKim0113 Isolated from Kimchi as a Starter Culture for the Production of Natural Pre-converted Nitrite

“…However, MRS medium supplemented with nitrate was used as a negative control and did not exhibit antimicrobial activity. Nitrite is also effective against other foodborne pathogens including Bacillus cereus, Enterococcus faecalis, Listeria monocytogenes, E. coli O157:H7, and Staphylococcus aureus in meat products (Buchanan et al, 1989;Harrison et al, 1998;Lee et al, 2016;Redondo, 2011;SAMESHIMA et al, 1997) Nitrate reduction and nitrite production (Gotterup et al, 2007). Marked, highly effective NaNO2 production by the most efficient strain S. hominis subsp.…”