Submitted to: Journal of Food Processing and Preservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/7/2017
Publication Date: N/A
Citation: N/A Interpretive Summary: Powdered infant formula (PIF) has been implicated as a transmission vehicle of Cronobacter sakazakii in food poisoning outbreaks. This emphasizes the need to better define and quantify the heat treatment given to PIF to provide an adequate degree of protection against survival of this deadly pathogen. We determined that a heat treatment at 56.0 degrees C for 28.5 min would kill more than one million bacteria in PIF. The predictive model developed can be used to estimate the time required at any temperature to kill a certain number of bacteria. This information will be of immediate use to the regulatory agencies and food industry in the development of guidelines to ensure elimination of Cronobacter in PIF.
Technical Abstract: Milk and whey powders are commonly used ingredients in powdered infant formula (PIF) and follow-up formula (FUF). In this study, Cronobacter sakazakii and Cronobacter dublinensis both of dairy origin and a reference strain, Cronobacter muytjensii ATCC 51329, were investigated for thermal inactivation (D and z values). Thermal inactivation of Cronobacter spp. were studied between 52 and 60 degrees C in trypic soy broth. Among the strains, C. muytjensii ATCC 51329 was the most heat resistant strain at lower temperatures (52 and 54 degrees C). The D52 and D54 values of C. muytjensii ATCC 51329 were 33.30 min and 6.79 min, respectively. At higher temperatures, e.g., 56, 58, and 60C, the local strains of C. sakazakii 131 and 807 had the highest D values. The D56 and D58 values were 4.73 min for C. sakazakii 131 and 2.30 min for C. sakazakii 807. The D60 values for C. sakazakii 131 and 807 were 1.17 and 1.14 min, respectively. The z-value of the reference strain (C. muytjensii ATCC 51329) was lower than the local strains at all temperatures tested. The findings of this study will be very helpful in understanding the heat resistance of C. sakazakii.