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Microbial quality of raw and ready-to-eat mung bean sprouts produced in Italy

Iacumin, Lucilla, Comi, Giuseppe
Food microbiology 2019 v.82 pp. 371-377
Listeria monocytogenes, Salmonella, Shiga toxin-producing Escherichia coli, bean sprouts, coliform bacteria, inoculum, microbial load, microbiological quality, mung beans, pathogens, plate count, ready-to-eat foods, seeds, sprouting, washing, Italy
The aim of this study was to determine the microbial quality of mung bean sprouts produced in Italy. The presence of pathogenic microorganisms (Shiga toxin-producing Escherichia coli (STEC), Salmonella spp. and Listeria monocytogenes), total coliforms, and total viable counts (TVCs) were determined. The study covered five years of sprout production. The results demonstrated that no pathogenic microorganisms were present, and the microbial load was less than 6 log CFU/g. The mung bean sprouts currently produced in Italy were found to be acceptable for consumption. An additional aim was to determine the fate of different strains of STEC, L. monocytogenes and Salmonella spp. by intentionally inoculating mung bean seeds during sprouting and by using chlorinated water to reduce the concentration of these strains in seeds and sprouts. The data demonstrated that these strains increased over 5–6 log CFU/g within 3 days from inocula. The chlorinated washing solution reduced the concentration of the investigated strains in seeds and sprouts by approximately 3 and 7 log CFU/g, respectively. However, it was not possible to completely eliminate the pathogens from either the mung bean seeds or sprouts. Despite these encouraging results, the producer's attention to hygienic quality should not be reduced when attempting to produce safe-to-consume mung bean sprouts.