Title: Efficacy of selected probiotic cultures to inhibit Enterobacter sakazakii ATCC 12868 in model reconstituted dairy products

Authors: Makuba A. Lihono; Aubrey F. Mendonca; Bledar Bisha; La Tanya Bankston; Terri D. Boylston

Addresses: Department of Human Sciences, University of Arkansas at Pine Bluff, 1200 N. University Drive, Mail Slot 4971, Pine Bluff, Arkansas 71601 USA. ' Department of Food Science and Human Nutrition, Iowa State University, 3399 Food Sciences Building, Ames, IA 50010, USA. ' Department of Animal Science, Colorado State University, 350 West Pitkin Street, Fort Collins, CO 80523-1171, USA. ' Arkansas Department of Health, 2306 Rike Drive, Pine Bluff, AR 71611, USA. ' Department of Food Science and Human Nutrition, 2547 Food Sciences Building, Iowa State University, Ames, IA 50011-1061, USA

Abstract: Enterobacter sakazakii ATCC 12868 (ES) is a very dangerous opportunistic organism likely to contaminate post-pasteurised dry milk products with a high mortality rate (40-80%). This study evaluated the antimicrobial efficacy of probiotics against ES in reconstituted dried infant formula. Initial study at 30C showed that Enterococcus faecium M-74 (EF) to exhibit the strongest inhibition when compared with Lactobacillus acidophilus 74-2 (LA) and Pediococcus acidilacticii (PA). In later study, initial populations of ES and EF were ~10² CFU/ml and 10⁹ CFU/ml in infant formula, respectively. At 12h, ES in controls at 30 and 35C increased to 6.54 and 7.95 log10 CFU/ml, respectively. At 12 hours, ES in formula (30C) with EF decreased to 0.52 log10 CFU/ml and was undetected (< 1.0 CFU/ml) at 35C. EF rapidly reduce the pH of the infant formula below pH 5.0 in the first four hours of fermentation at 35C, more than at 30C. The inhibitory effect of EF may be due to the acidification of the formula.

Keywords: probiotics; Enterobacter sakazakii; Lactobacillus acidophilus 74-2; Pediococcus acidilacticii; Enterococcus faecium M-74; infant formula; food pathogens; pathogen inhibitors; probiotic cultures; reconstituted dairy products; post-pasteurised dry milk.

DOI: 10.1504/IJFSNPH.2011.044623

International Journal of Food Safety, Nutrition and Public Health, 2011 Vol.4 No.2/3/4, pp.205 - 213

Published online: 27 Nov 2014 *

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