ScholarWorks@중앙대학교

초록

Cronobacter sakazakii is a foodborne pathogen associated with infections in infants through powdered infant formula (PIF). This study compared the acid resistance of four ATCC strains and four wild type isolates under conditions relevant to gastric and formula environments. Acid shock at pH 2.5 caused membrane leakage, with ATCC strains showing greater nucleic acid release, while wild type strains showed more protein leakage at later stages. At sublethal pH 3.5, wild type isolates maintained stable populations, whereas ATCC strains declined. Adaptation at pH 4.5 in reconstituted PIF, powdered skim milk (PSM), or media with lactose or casein increased D values for most ATCC strains, while wild type responses were inconsistent or reduced. These results highlight strain dependent heterogeneity in acid tolerance and demonstrate that prior exposure to mildly acidic formula environments can enhance survival under strong acid stress. Such variability should be considered in risk assessment of infant formula safety.

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