Evaluation of Potential for Butyl and Heptyl Para-Hydroxybenzoate Enhancement of Thermal Inactivation of Cronobacter sakazakii during Rehydration of Powdered Infant Powdered Infant Formula and Non-Fat Dry Milk.

Prior studies have demonstrated that parabens enhanced the thermal inactivation of foodborne pathogens including Cronobacter sakazakii , Salmonella enterica serotype Typhimurium, Escherichia coli O157:H7 and Listeria monocytogenes in model systems. However, there have been few studies looking at this phenomenon in actual food systems. The current study evaluated the potential enhancement of thermal inactivation of C. sakazakii by butyl para-hydroxybenzoate (BPB) in powdered infant formula (PIF) and non-fat dry milk (NFDM) before and after rehydration. When PIF was rehydrated with water at designated temperatures (65 – 80 ºC) in baby bottles, BPB did not enhance thermal inactivation. Rehydrated NFDM and lactose solutions with BPB were inoculated and heated at 58 ºC, BPB enhancement of thermal inactivation was negatively associated with NFDM levels in a dose-dependent manner, whereas presence of lactose retained thermal enhancement regardless of its concentration, suggesting an interaction between proteins and BPB. Fluorescence tests further indicated an interaction between BPB and the proteins in PIF and NFDM. Inoculated dry NFDM with and without BPB stored at 24 ºC and 55 ºC for 14 days did not substantially enhance inactivation in the dry state. This study suggests that BPB is not likely to enhance mild thermal inactivation treatments in foods that have appreciable amounts of protein.