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Increased thermal tolerance in Cronobacter sakazakii strains in reconstituted milk powder due to cross protection by physiological stresses
Journal of Food Safety ( IF 1.9 ) Pub Date : 2020-04-22 , DOI: 10.1111/jfs.12810
Rajni Chauhan 1 , Saurabh Bansal 2 , Wamik Azmi 1 , Gunjan Goel 2, 3
Affiliation  

Cronobacter sakazakii (C. sakazakii) is an opportunistic, neonatal, and food borne pathogen primarily associated with the contamination of powdered infant formula (PIF). The pathogen is reported to overcome the food safety barriers such as increased acidity, heat treatment, and so on. This study evaluates the thermal tolerance of C. sakazakii strains independently at 52, 55, and 58°C in reconstituted PIF after exposure to physiological stresses: refrigeration (4°C for 24 hr), starvation (37°C for 48 hr), and desiccation (25°C for 4 days). The Log10 CFU/ml and D‐values indicated that survival rate of all the strains decreased significantly (p < .05) after desiccation as compared to those of the control condition (without stress exposure). However, cold stress increased the thermal tolerance of all strains at all temperatures (52, 55, and 58°C) as indicated by increased D‐values. Among the tested strains, C. sakazakii strain N15 was found to be the most resistant to thermal treatment after each stress exposure as depicted by principal component analysis (PCA). No apparent correlation between thermal tolerance and starvation stress was observed. The findings indicate that prior exposure to stress conditions may induce cross protection to thermal treatment in C. sakazakii.

中文翻译:

由于生理压力的交叉保护,重组奶粉中阪崎肠杆菌的耐热性增加

阪崎肠杆菌C. sakazakii)是机会性,新生儿和食源性病原体,主要与婴儿配方奶粉(PIF)的污染有关。据报道,该病原体克服了食品安全性障碍,例如增加酸度,热处理等这项研究评估了在生理压力下冷藏后(4°C持续24小时),饥饿(37°C持续48小时),重组PIF在重组PIF中分别在52、55和58°C下对阪崎肠杆菌的耐热性和干燥(25°C 4天)。Log 10 CFU / ml和D值表明,所有菌株的存活率均显着降低(p <.05)与对照条件(无应力暴露)相比,干燥后。然而,如增加的D值所示,冷应力增加了所有菌株在所有温度(52、55和58°C)下的耐热性。如主成分分析(PCA)所示,在测试的菌株中,发现阪崎弯曲杆菌N15菌株在每次应力暴露后对热处理的抵抗力最强。在热耐受性和饥饿应力之间没有观察到明显的相关性。研究结果表明,预先暴露在应激条件下可能会导致阪崎茶的交叉保护。
更新日期:2020-04-22
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