TY - JOUR
T1 - Microbial methods for assessment of cleaning and disinfection of food-processing surfaces cleaned in a low-pressure system
AU - Bredholt, Sylvia
AU - Maukonen, Johanna
AU - Kujanpää, Kirsi
AU - Alanko, Timo
AU - Olofson, Ulla
AU - Hurmark, U.
AU - Sjöberg, Anna-Maija
AU - Wirtanen, Gun
PY - 1999
Y1 - 1999
N2 - An assessment system using various microbial methods was developed for the detection of residual, surface-attached microbes and soil on surfaces after sanitation. The microbial methods tested were: conventional cultivation, microscopy using image analysis after staining with acridine orange (AO), 5-cyano-2,3-ditolyl tetrazolium chloride/4′, 6-diamidino-2-phenylindole (CTC-DAPI) and LIVE/DEAD stains, impedance measurements, viable counts with 2,3,5-triphenyltetrazolium chloride (TTC) agar and ATP measurements. A test rig was used for the trials with four different low-pressure cleaning procedures (pressure <20 bar flow rate 27 l min–1). A strong alkaline foam cleaner, Trippel, and a mild alkaline foam cleaner, Topax 12, in combination with two disinfectants, respectively, were used. The disinfectants were peroxide-peracetic-acid-based Oxonia Aktiv and potassium-persulphate-based Virkon. Conventional cultivation combined with impedance measurements and image analysis of surfaces stained with AO, as well as CTC-DAPI, gave results that were comparable and complementary. The combination of these methods enabled a total evaluation of both the removal of biofilm and the killing of bacterial cells. The low-pressure cleaning system did not remove all of the bacterial cells from the surfaces and did not kill the bacteria even after use of the strong alkaline foam cleaner. The above-mentioned protocol carried out on the test rig can also be used to evaluate the sensitivity of microbial methods for use in certain industrial premises.
AB - An assessment system using various microbial methods was developed for the detection of residual, surface-attached microbes and soil on surfaces after sanitation. The microbial methods tested were: conventional cultivation, microscopy using image analysis after staining with acridine orange (AO), 5-cyano-2,3-ditolyl tetrazolium chloride/4′, 6-diamidino-2-phenylindole (CTC-DAPI) and LIVE/DEAD stains, impedance measurements, viable counts with 2,3,5-triphenyltetrazolium chloride (TTC) agar and ATP measurements. A test rig was used for the trials with four different low-pressure cleaning procedures (pressure <20 bar flow rate 27 l min–1). A strong alkaline foam cleaner, Trippel, and a mild alkaline foam cleaner, Topax 12, in combination with two disinfectants, respectively, were used. The disinfectants were peroxide-peracetic-acid-based Oxonia Aktiv and potassium-persulphate-based Virkon. Conventional cultivation combined with impedance measurements and image analysis of surfaces stained with AO, as well as CTC-DAPI, gave results that were comparable and complementary. The combination of these methods enabled a total evaluation of both the removal of biofilm and the killing of bacterial cells. The low-pressure cleaning system did not remove all of the bacterial cells from the surfaces and did not kill the bacteria even after use of the strong alkaline foam cleaner. The above-mentioned protocol carried out on the test rig can also be used to evaluate the sensitivity of microbial methods for use in certain industrial premises.
U2 - 10.1007/s002170050474
DO - 10.1007/s002170050474
M3 - Article
SN - 1438-2377
VL - 209
SP - 145
EP - 152
JO - European Food Research and Technology
JF - European Food Research and Technology
IS - 2
ER -