Detection and survival of Cronobacter sakazakii and Klebsiella pneumoniae in naturally fermented black carrot beverage

The safety of traditionally acidified black carrot (Daucus carota L) vegetable products requires mandatory investigation of growth and survival potential of pathogenic bacteria in stored and fermenting black carrot beverage. The traditional beverage was found to be enriched in neutraceuticals with pH 3.1 , TSS(0B) 3.4, titrable acidity(% lactic acid) 0.47%, brix: acid 8.51, total sugars 2.82%, reducing sugars 2.34%, ascorbic acid 480 mg/100ml, total phenols 39.60 mg/100ml and ?-carotene 82.96 ?g/l . With no sensorial defects in fermented beverage the microbiological analysis revealed the presence of Gram-negative pathogens (Cronobacter sakazakii strain WJ2275, accession number KF551983 and Klebsiella pneumonia strain HM2, accession number KF551984) capable of persisting during the initial stages of fermentation though they were quickly inactivated when analysed during the later stages of fermentation. Pathogens growth and survival was retarded as the pH decreased from 7.2 to 3.1 due to intense metabolism of bacterial strains but toxins produced by them may remain in the beverage as such. This contamination may have arisen as a consequence of treating soil with sewage sludge, manure and irrigation water. These studies have contributed to a better understanding of the behavior of emerging pathogens in acidified food products, thereby enabling the development of more effective strategies and interventions for its control like pre- pasteurization or development of consortia.