Premium
Quantitative Validation of Two Novel Selective Media for the Enumeration of B acillus cereus in Naturally Contaminated Fermented Sauce Samples
Author(s) -
Kim DongHyeon,
Chon JungWhan,
Kim Hyunsook,
Hwang DaeGeun,
Seo KunHo
Publication year - 2014
Publication title -
journal of food safety
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.427
H-Index - 43
eISSN - 1745-4565
pISSN - 0149-6085
DOI - 10.1111/jfs.12133
Subject(s) - cereus , food science , enumeration , bacillus cereus , agar , fermentation , mannitol , fermentation in food processing , food microbiology , biology , chemistry , microbiology and biotechnology , bacteria , biochemistry , mathematics , lactic acid , genetics , combinatorics
We compared two novel selective media, blood–yolk–polymyxin B –trimethoprim agar ( BYPTA ) and modified mannitol–yolk–polymyxin B agar ( mMYPA ), with mannitol–yolk–polymyxin B agar ( MYPA ) for the isolation and enumeration of B acillus cereus in naturally contaminated K orean fermented sauce samples such as red pepper paste, soybean paste, ssamjang and chunggukjang . A total of 81 fermented sauce samples were purchased from a local retail market in S eoul, S outh K orea. No statistical differences were observed in quantitative enumeration and isolation rates ( P > 0.05) among the three selective media. However, BYPTA and mMYPA exhibited higher selectivity than MYPA in excluding the background microflora. In addition, BYPTA (22/81, 27%) and mMYPA (21/81, 26%) detected more fermented sauces with unacceptable levels of B . cereus than MYPA (16/81, 20%) suggesting that the two novel selective media could be used to efficiently detect unacceptable levels of B . cereus in K orean fermented sauce. The two novel selective media could be powerful tools to enumerate the level of B . cereus in fermented sauce samples that have a high level of background microflora. Practical Applications In previous studies, we developed two novel selective media, BYPTA and mMYPA for the enumeration of B acillus cereus in foods. It is well known that naturally fermented K orean soybean sauces are commonly contaminated with B . cereus , and a high level of background microflora in these foods could behave competitively during the detection of B . cereus . These sauces are also commonly consumed without additional heat treatment. Therefore, highly specific and sensitive media for the enumerative detection of B . cereus in the fermented sauces are needed. In this study, we found that the two novel selective media exhibited greater selectivities and isolation capabilities for B . cereus in the fermented sauces than MYPA . In addition, BYPTA and mMYPA detected more fermented sauces with unacceptable levels of B . cereus than MYPA . We recommend these two media be used in food manufacturing plants and food safety authorities to monitor B . cereus in fermented sauces that have a high level of background microflora.