Microbiological quality of frozen "edamame" (vegetable soybean)

Khalid, M. F.
Pao, S.
Ettinger, M. R.
Mebrahtu, T.
Mullins, C.
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This study compared the microbiological quality of frozen “edamame” to other varieties of frozen beans sold in Virginia. Furthermore, the reduction of microorganisms during experimental edamame processing was investigated. Commercial frozen in-pod and shelled edamame had aerobic mesophiles at 3.4 and 3.1 log cfu/g, yeasts and molds at 2.3 and 2.1 log cfu/g, and some contained low levels of Escherichia coli and enterotoxigenic Bacillus spp. Salmonellae were not found; however, 5% edamame and 4% frozen beans in general were positive for Listeria monocytogenes. Rinsing and shelling raw edamame caused a 1–2 log reduction of total aerobic mesophile, yeast and mold, and coliform counts. No naturally occurring yeast, mold or coliform was detected after blanching edamame at 98C for 30 s. Blanching for 60 s eliminated approximately 6 log cfu/g of inoculated E. coli and Listeria from in-pod edamame. Adequate processing ensures the microbial quality and safety of frozen edamame.