熏煮火腿中志贺氏菌的热失活特性

Thermal Inactivation Properties of Shigella in Smoked Cooked Ham

为了研究志贺氏菌不同菌株在熏煮火腿中热失活规律,以55、63℃对接种108 CFU/g志贺氏菌的熏煮火腿进行热处理,测定处理后样品中志贺氏菌的残存菌体浓度。应用Logistic模型和3rd degree polynomial模型拟合在两种温度下志贺氏菌的动力学模型,用D值(decimal reduction time)表示志贺氏菌在熏煮火腿中的耐热情况。结果表明:11株志贺氏菌的热失活曲线运用3rd degree polynomial拟合较好,相关系数均在0.98以上。志贺氏菌不同菌株的D值不同,55℃条件下志贺氏菌在熏煮火腿中的D值为4.46~10.66 min,63℃条件下D值为0.48~3.22 min。不同菌株之间抗热性存在差异,其中菌株S-5的耐热性最强,S-6最弱。

This study aimed to examine the thermal inactivation pattern of Shigella in smoked cooked ham. Shigella (108 CFU/g) were inoculated into smoked cooked ham, cultured at constant temperature and constant humidity and then subjected to thermal treatment at 55 or 63 ℃. The number of surviving cells was counted on selective media. A Logistic model and a 3rd degree polynomial model were separately used to fit the thermal inactivation curve by CurveExpert software. Decimal reduction time (D values) represented the heat resistance of Shigella. The results showed that the curves for 11 Shigella strains fitted by the 3rd degree polynomial model were better, with correlation coefficients (R2) above 0.98.The D values of different Shigella strains were different, ranging from 4.46 to 10.66 min at 55 ℃ and from 0.48 to 3.22 minat 63 ℃ in the inoculated smoked cooked ham. The heat resistance of different Shigella strains were different, and strain S-5 had the strongest heat resistance while S-6 was the weakest.