title: Inactivation and removal of Bacillus cereus by sanitizer and detergent.
abstract: This study was conducted to compare the susceptibility of planktonic cells, attached single cells and biofilm cells of Bacillus cereus to sodium hypochlorite and Spartec, a quaternary ammonium compound (QAC). Removal of B. cereus biofilm by simulating clean-in-place (CIP) procedures employing 1.5% Spec-Tak 1000, an alkaline detergent; 0.65% Dilac, an acid detergent and 1.5% Diverform Plus, a sodium hypochlorite containing alkaline detergent was also examined. The results show that B. cereus cells in a biofilm were most resistant to chemical sanitizers followed by the attached single cell and cells in a planktonic state. When B. cereus cells were in a planktonic state, 25 ppm hypochlorite or 100 ppm QAC induced a more than 5.0 log CFU/ml reduction of cell numbers within 15 s. However, the same sanitizer used in this study showed little effect on cells in a biofilm even when the exposure time was extended to 5 min. The sanitizers tested were less effective against cells in biofilm formed on milk pre-soiled than on unsoiled stainless steel chips. It was also noted that Spec-Tak 1000 treatment at 70 degrees C for 10 min and water rinse in the first step of the long-hot CIP procedure can effectively remove the biofilm B. cereus cells from the milk pre-soiled stainless chip. With this long-hot CIP procedure, the biofilm cells of B. cereus were removed by ca. 6.10 log CFU/chip compared to ca. 1.47 log CFU/chip noted in the control procedure.
authors.affiliation: Graduate Institute of Food Science and Technology, National Taiwan University, Taipei.
authors.forename: Jui-Sen
authors.initials: JS
authors.lastname: Peng
authors.forename: Wei-Chong
authors.initials: WC
authors.lastname: Tsai
authors.forename: Cheng-Chun
authors.initials: CC
authors.lastname: Chou
mesh_terms: D001409:Bacillus cereus / Q000187:drug effects*; D018441:Biofilms / Q000187:drug effects; D015169:Colony Count, Microbial; D003902:Detergents / Q000494:pharmacology*; D004202:Disinfectants / Q000494:pharmacology*; D005516:Food Microbiology; D006863:Hydrogen-Ion Concentration; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology*; D012973:Sodium Hypochlorite / Q000494:pharmacology*; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D003902:Detergents; D004202:Disinfectants; D000644:Quaternary Ammonium Compounds; D012973:Sodium Hypochlorite