UNASSIGNED:确定微生物热灭活动力学的不同方法会导致热阻值的差异。在这项研究中,用三种方法测定全脂奶粉中沙门氏菌的热阻:水浴中热死亡时间(TDT)盘,在水浴袋,还有TDT三明治系统.将来自三个生产批次的全脂奶粉的样品接种五株沙门氏菌混合物,并平衡至0.20的水活度。然后在75、80或85°C下对样品进行三次等温处理。在六个时间点取出样品,并对幸存者进行培养计数。将失活数据拟合到两个合并模型:两个主要模型(对数线性和Weibull)和一个次要模型(Bigelow)。正态检验表明,所有模型参数均为正态分布。两个综合模型的模型参数均无显著差异(α=0.05)。出现时间期间的失活量在方法之间也没有显着差异(α=0.05)。然而,TDT三明治在出现时间内导致较少的失活,并且模型参数的总体变化较小。将来自所有三种方法的幸存者数据组合并拟合到两个合并模型中。威布尔具有较低的均方根误差和较好的拟合度,根据校正后的Akaike\的信息标准。三种热处理方法产生的结果没有显着差异;因此,这些方法是可以互换的,至少全脂奶粉中的沙门氏菌.与更多方法进行比较,其他微生物,以及使用本研究中提出的相同框架的更多种类的食品可以为标准化食品中微生物的热灭活动力学研究提供指导。
UNASSIGNED: Different methods for determining the thermal inactivation kinetics of microorganisms can result in discrepancies in thermal resistance values. In this
study, thermal resistance of Salmonella in whole milk powder was determined with three methods: thermal death time (TDT) disk in water bath, pouches in water bath, and the TDT Sandwich system. Samples from three production lots of whole milk powder were inoculated with a five-strain Salmonella cocktail and equilibrated to a water activity of 0.20. The samples were then subjected to three isothermal treatments at 75, 80, or 85°C. Samples were removed at six time points and cultures were enumerated for survivors. The inactivation data were fitted to two consolidated models: two primary models (log linear and Weibull) and one secondary model (Bigelow). Normality testing indicated that all the model parameters were normally distributed. None of the model parameters for both consolidated models were significantly different (α = 0.05). The amount of inactivation during the come-up time was also not significantly different among the methods (α = 0.05). However, the TDT Sandwich resulted in less inactivation during the come-up time and overall less variation in model parameters. The survivor data from all three methods were combined and fitted to both consolidated models. The Weibull had a lower root mean square error and a better fit, according to the corrected Akaike\'s information criterion. The three thermal treatment methods produced results that were not significantly different; thus, the methods are interchangeable, at least for Salmonella in whole milk powder. Comparisons with more methods, other microorganisms, and larger varieties of food products using the same framework presented in this
study could provide guidance for standardizing thermal inactivation kinetics studies for microorganisms in foods.
CONCLUSIONS: