[关键词]
[摘要]
以有氧贮藏养殖大黄鱼的特定腐败菌腐败希瓦氏菌为研究对象,通过pH、Aw、NaCl和温度调控其生长/非生长状况,并分析其对生长动力学参数的影响,为有效抑制特定腐败菌增殖,延长产品货架期提供支持。将腐败希瓦氏菌接种于TSB中培养,测定不同调控因子下OD动态数据,确定生长/非生长界限,在生长范围内用修正的Gompertz方程进行拟合,对模型的拟合优度及调控因子对动力学参数的影响进行研究。实验表明,15 ℃时,pH≤5.0或Aw≤0.930或NaCl≥7%时,腐败希瓦氏菌不生长;25 ℃时,pH≤5.0或Aw≤0.920或NaCl≥12%时,腐败希瓦氏菌不生长;37 ℃时,腐败希瓦氏菌均不生长。腐败希瓦氏菌生长模型拟合显示,不同pH、Aw和NaCl对其最大比生长速率和迟滞期有较大影响,模型的R2、偏差度和准确度接均接近1,均方根误差接近0,表明模型能较好地拟合不同条件下的腐败希瓦氏菌的生长。
[Key word]
[Abstract]
Isolates of the spoilage organism Shewanella putrefaciens from farmed Pseudosciaena crocea stored in aerobic conditions were studied. The growth of S. putrefaciens was regulated by pH, water activity (Aw), sodium chloride (salt), and temperature, and the effect of regulatory factors on the growth kinetic parameters was analyzed. This study can aid in effectively inhibiting spoilage and bacterial growth to extend the shelf life of products. S. putrefaciens was inoculated in tryptic soy broth (TSB), and real-time optical density (OD) data were measured in different environmental conditions to determine the growth/no growth boundary. The OD data were fitted to a modified Gompertz equation in the growth range, and the goodness of fit of the model and the effect of regulatory factors on kinetic parameters were studied. The experimental results showed that at 15 ℃, S. putrefaciens could not grow at pH ≤ 5.0, Aw ≤ 0.930, or salt ≥ 7%. At 25 ℃, S. putrefaciens could not grow at pH ≤ 5.0, Aw ≤ 0.920, or salt ≥ 12%. At 37 ℃, S. putrefaciens could not grow. The goodness of fit of the growth model for S. putrefaciens showed that pH, Aw, and salt had a considerable effect on the maximum specific growth rate and lag phase of S. putrefaciens. The R2, bias, and accuracy values of the model were all near 1, and root mean square error (RMSE) was close to 0, indicating that the model is a good fit for the growth of S. putrefaciens in different conditions.
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[基金项目]
国家自然科学基金项目(31371867);中央级公益性科研院所基本科研业务费专项资金(2011M04,2014G02)