Model to Predict Growth/No Growth Interfaces of Enterococcus as A Function of NACl and NANO2

Abstract

This study developed growth/no growth models to describe the effect of NaNO2 and NaCl on Enterococcus growth. Enterococcus spp. were incubated in deMan, Rogosa and Sharpe broth formulated with NaNO2 (0–210 ppm) and NaCl (0–1.75%) at 4–15C up to 1,080 h under aerobic and anaerobic conditions. Growth responses (growth: 1 or no growth: 0) for all the combinations were collected. The growth response data (NaNO2 × NaCl × storage time) for each temperature and packaging condition were analyzed by logistic regression. The developed model showed that NaNO2 and NaCl influenced Enterococcus growth, but a combination effect of NaNO2 and NaCl was observed at 7C and 15C, and at 7C, 10C and 12C under aerobic and anaerobic conditions, respectively. Under the conditions at which a combination effect was observed, the antimicrobial effect of NaNO2 increased as NaCl concentration increased. Validation showed a high concordance rate (90%). The results indicate that the developed models may be useful for describing the effect of NaNO2 and NaCl on Enterococcus growth. Practical Application NaCl and NaNO2 are widely used as preservative agents in meat processing, but Enterococcus are resistant to antimicrobial activities of NaCl and NaNO2. Thus, Enterococcus may cause spoilage in meat products such as frankfurters. The developed growth/no growth model can be used to predict the growth probabilities of Enterococcus in the combination of NaCl and NaNO2, which may be useful in predicting Enterococcus growth in meat products.