Inactivation and Removal of Bacillus Cereus by Sanitizer and Detergent

Int J Food Microbiol. 2002 Jul 25;77(1-2):11-8. doi: 10.1016/s0168-1605(02)00060-0.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacillus cereus / drug effects*
  • Biofilms / drug effects
  • Colony Count, Microbial
  • Detergents / pharmacology*
  • Disinfectants / pharmacology*
  • Food Microbiology
  • Hydrogen-Ion Concentration
  • Quaternary Ammonium Compounds / pharmacology*
  • Sodium Hypochlorite / pharmacology*
  • Time Factors
  • Treatment Outcome


  • Detergents
  • Disinfectants
  • Quaternary Ammonium Compounds
  • Sodium Hypochlorite