Abstract: To explore the effect of acid and osmotic pressure on the growth of planktonic and detached cells of Salmonella enteritis, the Baranyi model and modified square root model were used to simulate the growth of S. enteritis in the two states, respectively. The growth of attached cells cultivated for 7 days under different environments was studied as well. The experimental results demonstrated that both the planktonic and detached cells pre-cultivated at 25 ℃ for 72 h showed similar growth rates under most subsequent environmental conditions (P ≥ 0.05). However, the growth curves and growth kinetic parameters of both cells were significantly different (P < 0.05) under four conditions including pH 5.0 + 0.0 g/100 mL NaCl, pH 7.0 + 4.0 g/100 mL NaCl, pH 6.0 + 4.0 g/100 mL NaCl, and pH 5.0 + 4.0 g/100 mL NaCl. Moreover, the first- and second-order models showed high determination coefficient (R2) and low root mean square error, and the model parameters Aw min, pHmin, as well as the evaluation indicators accuracy factor (Af) and deviation factor (Bf) were within the acceptable range under the experimental conditions of pH 5.0–7.0 and NaCl concentration of 0.0–4.0 g/100 mL. The initial adsorbance quantity of attached cells cultivated at 25 ℃ for 72 h was (5.604 ± 0.117) (lg (CFU/cm2)), and the value reduced gradually with the decrease in pH value or the increase in NaCl concentration after subsequent cultivation for 7 days under different acid and osmotic pressures. Consequently, this research could provide a reference for understanding and controlling the growth of S. enteritis in different states during food processing.

Key words: acid, osmotic pressure, Salmonella enteritis, physiological states