Open AccessAssessing of adaptation ability of Listeria to benzalkonium chloride (BAC) by determination of its minimal inhibitory concentration
Author(s) -
Monika Podpac,
Barbara Jeršek
Publication year - 2019
Publication title -
acta agriculturae slovenica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.217
H-Index - 17
eISSN - 1854-1941
pISSN - 1581-9175
DOI - 10.14720/aas.2019.114.1.15
Subject(s) - listeria , broth microdilution , listeria monocytogenes , benzalkonium chloride , minimum inhibitory concentration , disinfectant , microbiology and biotechnology , bacteria , biology , minimum bactericidal concentration , food science , antimicrobial , chemistry , chromatography , genetics , organic chemistry
Bacteria of the genus Listeria pose a problem in the food industry due to their wide distribution and their good survival in adverse conditions. L. monocytogenes (E. Murray et al. 1926) Pirie 1940 is human pathogen, while L. innocua Seeliger (ATCC ® 33090 ™ ) as not pathogenic bacteria is the most often found listeria in food production environment. Disinfectants represents an important part of Listeria management in food processing environments and benzalkonium chloride (BAC) is used frequently. The purpose of the work was to determine whether strains of listeria can adapt to BAC. To carry out the adaptation, a precise determination of antibacterial activity of BAC was needed. Firstly minimum inhibitory concentration (MIC MTP ) of BAC was determined with broth microdilution method for each Listeria strain. Then, we checked whether MIC MTP was indeed the lowest concentration of BAC, which had an influence on growth of strains with growth curves. We found out that growth inhibitory effect (MIC GC ) was achieved at concentrations of BAC that were lower than MIC MTP (0.1-0.5x of MIC MTP values). Adaptation of listeria to BAC was therefore performed by using 0.25x MIC GC as the initial BAC concentration. Results showed that 50 % of the strains were able to adapt to BAC, and in L. monocytogenes ŽM500 this adaptation was even stable. The broth microdilution method was useful for approximate assessment of antimicrobial activity of BAC, while for the more precise determination of disinfectant activity it is necessary to determine it by using another method such as plate count method.