PCR Detection of Bacillus and Staphylococcus in Various Foods
1271 Journalof Food Protection, Vol. 67, No. 6, 2004, Pages 1271– 1277 Copyright q,International Association forFood Protection Research Note PCR Detection of Bacillus and Staphylococcus inV ariousFoods SHIGERU NAKANO, * TORU KOBAYASHI, KENICHI FUNABIKI, ATSUSHI MATSUMURA, YASUHIRO NAGAO, AND TOSHIHIRO YAMADA FoodSafety Research Institute,Nissin Food Products Co. Ltd., 2247, Noji-cho, Kusatsu, Shiga 525-0055, Japan MS03-403: Received 10September 2003/ Accepted 25January 2004 Downloaded from http://meridian.allenpress.com/jfp/article-pdf/67/6/1271/1677289/0362-028x-67_6_1271.pdf by guest on 01 October 2021 ABSTRACT Abroad-rangePCR assayfor the detection of bacteria belonging to Bacillus and Staphylococcus generawas developed. Primerstargeting the bacterial 16S rRNA genewere newly designed and used in a PCR assay.T odeterminethe speci city ofthe assay, 81 different bacterial strains (of 50 genera), 2 fungi,3 animals,and 4 plantswere tested. Results were positive forevery tested Bacillus,Staphylococcus, or Aerococcus strain.In addition, the result for Listeriagrayi waspositive with lowerPCR product.For all other bacterial strains and eukaryotes tested, results were negative. Bacterial DNA wasprepared withthe use of achromopeptidase and Chelex 100 resin from culture after growth in brain heart infusion medium. T otestthe sensitivityof this PCR assayfor Bacillus or Staphylococcus genus,either Bacilluscereus or Staphylococcusaureus was inoculatedinto various foods with undetectable levels of endogenous microbial contamination as an indicator .Inoculationof bacteriaat 10 to 30 CFU/ goffood was followed by a 5-henrichment culture step after which the PCR assayallowed the detectionof bacterial cells. When the inoculation ( B. cereus or S. aureus)of10 to 90 CFU/ gintonoodle foods containing endogenousmicro ora (10 3 to 105 CFU/g)wasfollowed by a6-henrichment culture step, the PCR assaydetected the bacteria.
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