单增李斯特菌的生长特性及其在冷藏牛奶中的预测模型
Growth properties of Listeria monocytogenes and predicting models in refrigerated milk
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摘要: 通过测定单增李斯特菌菌株在不同培养条件下菌液的OD600值,绘制生长曲线,分析培养基成分、温度、p H、Na Cl浓度、接种量以及转速对单增李斯特菌生长的影响,并选取Gompertz方程、Logistic方程和Hill方程建立单增李斯特菌在冷藏牛奶中的生长模型。结果表明:菌株在TSB-YE和MRS培养基中生长良好;能够耐受0.5%3%的Na Cl浓度范围;最适生长温度为37℃,最适生长p H为8,对氧气的需求量表现不明显。菌株可在4℃冷藏的全脂牛奶中缓慢生长,达到稳定期的菌数有2 lg CFU/m L的增长,Gompertz和Logistic方程模型可用于预测其生长情况。Abstract: Listeria monocytogenes growth was evaluated by determining OD600 value and analyzing growth curves of strain in different conditions including culture ingredients,temperatures,p H values,Na Cl concentrations,inoculation amounts and rotation rates. The Gompertz,Logistic and Hill models were used to establish the growth models of L. monocytogenes in refrigerated milk.Results showed that the strain was grown well in TSB- YE and MRS medium and tolerant with 0.5% ~ 3%Na Cl concentrations. The optimal temperature was 37 ℃ and the optimal p H value was about 8 for growth. The oxygen demanding was not obvious for this strain. Cells were grown slowly in whole- fat milk at 4 ℃ with 2 lg CFU / m L increasing after attaining stationary phase,which Gompertz and Logistic models could be used in prediction of L.monocytogenes growth.
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