Growth of healthy and sanitizer-injured Salmonella cells on mung bean sprouts in different commercial enrichment broths.
The ability of nine commercial broths to enrich healthy and 90% sanitizer-injured Salmonella Typhimurium and Salmonella cocktail on mung bean sprouts was evaluated to select an optimum broth for detection. Results showed that S. Typhimurium multiplied faster and reached a higher population in buffered peptone water (BPW), Salmonella AD media (AD) and ONE broth-Salmonella (OB), compared with other broths. Healthy and 90% sanitizer-injured Salmonella at low concentrations increased by 4.0 log CFU/ml in these three broths. However, no Salmonella growth was observed in lactose broth (LB). Further investigation showed that during incubation, pH of LB dropped from 6.7 to 4.2, due to production of lactic (66 mM) and acetic acids (62 mM) by lactic acid bacteria that were identified as dominant microbiota in bean sprouts. Though no cell membrane damage was detected by propidium monoazide combined with real-time PCR, it was found that LB inhibited Salmonella growth, especially from low inoculum levels. This study suggests that in consideration of effectiveness and cost, BPW would be a suitable enrichment broth to use for isolating and detecting Salmonella on mung bean sprouts, while using LB might cause false negative results in Salmonella detection by either PCR or standard cultural method.
Food Science & Technology Programme, Department of Chemistry, National University of Singapore, Science Drive 4, 117543, Singapore.
Qianwang
Q
Zheng
Food Science & Technology Programme, Department of Chemistry, National University of Singapore, Science Drive 4, 117543, Singapore; Chair of Industrial and Food Microbiology, Faculty of Food Science, University of Warmia and Mazury in Olsztyn, Plac Cieszyński 1, 10-726, Olsztyn, Poland.
Marta
M
Mikš-Krajnik
Food Science & Technology Programme, Department of Chemistry, National University of Singapore, Science Drive 4, 117543, Singapore.
Craig
C
D'Souza
Food Science & Technology Programme, Department of Chemistry, National University of Singapore, Science Drive 4, 117543, Singapore.
Yishan
Y
Yang
Department of Food Science and Biotechnology, Kyungnam University, Changwon, 631-701, South Korea.
Da-Jeong
DJ
Heo
Department of Food Science and Biotechnology, Kyungnam University, Changwon, 631-701, South Korea.
Si-Kyung
SK
Kim
Department of Food Science and Biotechnology, Kyungnam University, Changwon, 631-701, South Korea.
Seung-Cheol
SC
Lee
Food Science & Technology Programme, Department of Chemistry, National University of Singapore, Science Drive 4, 117543, Singapore; National University of Singapore (Suzhou) Research Institute, No. 377 Linquan Street, Suzhou Industrial Park, Suzhou, Jiangsu, 215123, China. Electronic address: chmyukhg@nus.edu.sg.
Hyun-Gyun
HG
Yuk
D003257:Consumer Product Safety; D003470:Culture Media / Q000737:chemistry; D007887:Fabaceae / Q000254:growth & development / Q000382:microbiology*; D005506:Food Contamination / Q000032:analysis* / Q000191:economics; D018525:Germination; D012486:Salmonella typhimurium / Q000235:genetics / Q000254:growth & development* / Q000302:isolation & purification; D012639:Seeds / Q000254:growth & development / Q000382:microbiology; D014675:Vegetables / Q000191:economics / Q000382:microbiology*
D003470:Culture Media
Enrichment broths; Injury; Lactose broth; Mung bean sprouts; Salmonella