Inhibition of Salmonella Typhimurium and Listeria Monocytogenes in MungBean Sprouts by Chemical Treatment

Inhibitionof Salmonella Typhimurium and Listeria Monocytogenes in Mung Bean Sprouts byChemical Treatment

Journal of Food Protection Volume: 65 Number: 7 Page: p1088 — p1092
Sun-Young Lee; Kyung-Mi Yun; J. Fellman; Dong-Hyun Kang

This study was undertakento compare the efficacies of chlorous acid (268 ppm), sodium hypochlorite (200ppm), and lactic acid (2%) in eliminating total mesophilic microorganisms,Salmonella Typhimurium, and Listeria monocytogenes on commercial mung beansprouts immediately after treatment and during posttreatment refrigeratedstorage. Treatment with sodium hypochlorite for 10 min did not reduce the totalaerobic count. However, treatment with lactic acid and chlorous acid for 10 mininitially reduced the total aerobic count by 0.6 and 0.8 log CFU/g,respectively, and maintained the same level or a lower level of the totalaerobic count during the storage time. Treatment with chlorous acid reducedSalmonella Typhimurium from 5.0 log to undetectable levels (<0.48 log CFU/g),and the pathogen remained undetectable over a 9-day storage period. Treatmentwith lactic acid resulted in an initial 3-log reduction and further reduced thenumber of Salmonella Typhimurium cells to undetectable levels after 3 days. ForL. monocytogenes, treatment with chlorous acid resulted in an initial 5-logreduction, and treatment with lactic acid resulted in a 2-log reduction at thebeginning and undetectable levels after 9 days. When chemically injured cellswere investigated by the selective overlay method, no statistical difference wasobserved (P < 0.05) between the number of injured cells recovered followingtreatment with chlorous acid and the number of bacteria counted on selectivemedia, whereas sodium hypochlorite generated more injured cells than the othertreatments did. These data suggest that treatment with chlorous acid may beuseful in reducing total mesophilic microorganisms, Salmonella Typhimurium, andL. monocytogenes in commercial mung bean sprouts.