Abstract
Cronobacter sakazakii is an emerging pathogen that can cause diseases for several infant groups. These bacteria were contaminated in foods, clinical utensils, and environments. In Indonesia, C. sakazakii has been isolated from powdered infant formulas, weaning foods, and other dried foods such as cornstarch. The objective of this research is to trace survival of C. sakazakii during cornstarch production step using its mutant. Mutant was constructed by inserting Green Fluorescent Protein plasmid inside to the bacterial cell that appeared green fluorescent colonies under UV observation. The presence of C. sakazakii during processing was conducted by artificial contamination. This research consists of three steps, i.e. determination of the suitable enumeration method of C. sakazakii’s mutant, cornstarch production from yellow corn, and survival analysis of C. sakazakii during endosperm soaking and cornstarch drying. The suitable enumeration method was surface plating method on TSA-ampicillin medium combining with UV light application because of ineffectiveness of ampicillin inhibition for growth of yeasts and molds. The cornstarch produced in laboratory has the same properties with commercial cornstarch in parameters of moisture content, density, and starch granule structure. The yield of cornstarch final product was 48.90% (dry whole kernel-based). C. sakazakii cannot survive in 48 hours soaking process at 52?C and 24 hours drying process at 50?C that is applied during cornstarch production.
Highlights
Cronobacter sakazakii is a gram-negative bacterium which is included into genus of Cronobacter spp
Microorganisms used in this study were GFPuv labeled of C. sakazakii FWHc3 and YRt2a constructed from previous research [9], yeasts (Kodamaea ohmeri, Candida krusei, Candida zeylanoides), and molds (Aspergillus flavus, Aspergillus niger, Fusarium oxysporum) and lactic bacteria (Pediococcus sp., Lactobacillus plantarum, Lactobacillus lactis, Lactobacillus brevis) isolated from previous research [10]
The plates were incubated at 30 ̊C and at 37 ̊C for 48 hours
Summary
Cronobacter sakazakii is a gram-negative bacterium which is included into genus of Cronobacter spp. (previously known as Enterobacter sakazakii). C. sakazakii is an opportunistic pathogen that causes meningitis and necrotizing enterocolitis for adverse condition of infant groups. These cases are associated with infant formulae. The data reported by FAO-WHO [6] showed that the ingredient added through dry mixing process was one of the sources of Cronobacter spp. contaminant in powder infant formulae. Current researches supported this issue, Dewanti-Hariyadi et al [7] have isolated Cronobacter spp. from cornstarch and Fiegen [8] have isolated the pathogen form cornstarch and other ingredients (lecithin, potato starch, rice starch and wheat starch)
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