不同温度条件下养殖大菱鲆菌群变化和货架期预测

对低温(0~10℃)、室温(25℃)和变温贮藏条件下养殖大菱鲆的细菌种群变化进行研究,确定不同温度条件下养殖大菱鲆的优势腐败菌和货架期,并采用Exponential、School-field和Square-root方程构建货架期预测模型,并对货架期预测模型的适用性进行评价和验证。结果显示,低温贮藏大菱鲆货架期为6.1~32.6 d,优势腐败菌为腐败希瓦氏菌(40.3%)和假单胞菌属(27.4%),室温时货架期为1.3 d,优势腐败菌为气单胞菌(47.1%)和腐败希瓦氏菌(29.4%);构建的Exponential、School-field和Square-root货架期模型参数分别为温度特征系数a=0.12,T_(min)=-6.6℃,表观活化能(E_a)为81.4 k J/mol,采用均方根误差、残差平方和、偏差度、准确度对模型的拟合优度进行比较,Square-root模型预测性能最优,用恒温和变温对3种货架期预测模型进行验证,显示Square-root货架期模型误差最小,可有效预测恒温和变温条件下大菱鲆的货架期。

Shelf Life Prediction and Spoilage Bacteria Changes of Farmed Turbot (Scophthalmus maximus) at Different Storage Temperatures

Changes in physicochemical indicators and bacterial flora of farmed Scophthalmus maximus stored at low (0–10 ℃), ambient and fluctuating temperatures were determined. Meanwhile, the predominant spoilage organisms and shelf life under the three storage conditions were also studied, and shelf-life predictive models were fitted by means of Exponential, School-field and Square-root equations, respectively and their goodness of fit was evaluated. The results showed that the shelf life of farmed Scophthalmus maximus was 6.1–32.6 days at low temperature, and the predominant spoilage bacteria were Shewanella putrefaciens (40.3%) and Pseudomonas spp. (27.4%); the shelf life was 1.3 days at room temperature, and the predominant spoilage bacteria were Aeromonas spp. (47.1%) and Shewanella putrefaciens (29.4%). The temperature characteristic coefficient a, theoretical minimum temperature Tmin and activation energy Ea from the Exponential, Schoolfield and Square-root models were 0.12, –6.6 ℃ and 81.4 kJ/mol, respectively. The goodness of fit of the three models was compared by accuracy factor (Af), bias factor (Bf), root mean square error (RMSE) and mean residual error (MRE), and the predictive ability of the Square-root model was better than that of other models. The model predictions were experimentally validated under isothermal and non-isothermal conditions, and the relative error of the Square-root model was lower than that of the other models, suggesting that it could be used as a reliable to accurately predict the shelf life of farmed Scophthalmus maximus under isothermal and non-isothermal conditions.