TY - JOUR
T1 - Synergistic bactericidal action of phytic acid and sodium chloride against Escherichia coli O157
T2 - H7 cells protected by a biofilm
AU - Kim, Nam Hee
AU - Rhee, Min Suk
N1 - Funding Information:
This work was supported by Korea Institute of Planning and Evaluation for Technology in Food, Agriculture, Forestry and Fisheries (IPET) through High Value-added Food Technology Development Program, funded by Ministry of Agriculture, Food and Rural Affairs (MAFRA) ( 314046-3 ). The authors thank School of Life Sciences and Biotechnology of Korea University for BK 21 PLUS and the Institute of Biomedical Science and Food Safety, CJ-Korea University Food Safety Hall, for providing the equipment and facilities.
Publisher Copyright:
© 2016 Elsevier B.V.
Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2016/6/16
Y1 - 2016/6/16
N2 - The food industry must prevent the build-up of strong Escherichia coli O157:H7 biofilms in food processing environments. The present study examined the bactericidal action of phytic acid (PA), a natural extract from rice bran and the hulls/peels of legumes, against E. coli O157:H7 biofilms. The synergistic bactericidal effects of PA plus sodium chloride (NaCl) were also examined. E. coli O157:H7 biofilms were allowed for form on stainless steel coupons by culture in both rich (tryptic soy broth, TSB) and minimal (M9) medium at 22 °C for 6 days. Bacterial cells within biofilms grown in M9 medium were significantly more resistant to PA than those grown in TSB (p < 0.05); thus M9 medium was selected for further experiments. The anti-biofilm effect of PA was significantly increased by addition of NaCl (2-4%) (p < 0.05); indeed, the combination of 0.4% PA plus 3-4% NaCl completely inactivated E. coli O157:H7 biofilms without recovery (a > 6.5 log CFU/cm2 reduction). Neither PA nor NaCl alone were this effective (PA, 1.6-2.7 log CFU/cm2 reduction; NaCl, <0.5 log CFU/cm2 reduction). Confocal laser scanning microscopy images of propidium iodide-treated cells showed that PA (0.4%) plus NaCl (2-4%) had marked membrane permeabilizing effects. These results suggest that a sanitizer that combines these two naturally occurring antimicrobial agents may be useful to food safety managers who encounter thick biofilm formation in food processing environments.
AB - The food industry must prevent the build-up of strong Escherichia coli O157:H7 biofilms in food processing environments. The present study examined the bactericidal action of phytic acid (PA), a natural extract from rice bran and the hulls/peels of legumes, against E. coli O157:H7 biofilms. The synergistic bactericidal effects of PA plus sodium chloride (NaCl) were also examined. E. coli O157:H7 biofilms were allowed for form on stainless steel coupons by culture in both rich (tryptic soy broth, TSB) and minimal (M9) medium at 22 °C for 6 days. Bacterial cells within biofilms grown in M9 medium were significantly more resistant to PA than those grown in TSB (p < 0.05); thus M9 medium was selected for further experiments. The anti-biofilm effect of PA was significantly increased by addition of NaCl (2-4%) (p < 0.05); indeed, the combination of 0.4% PA plus 3-4% NaCl completely inactivated E. coli O157:H7 biofilms without recovery (a > 6.5 log CFU/cm2 reduction). Neither PA nor NaCl alone were this effective (PA, 1.6-2.7 log CFU/cm2 reduction; NaCl, <0.5 log CFU/cm2 reduction). Confocal laser scanning microscopy images of propidium iodide-treated cells showed that PA (0.4%) plus NaCl (2-4%) had marked membrane permeabilizing effects. These results suggest that a sanitizer that combines these two naturally occurring antimicrobial agents may be useful to food safety managers who encounter thick biofilm formation in food processing environments.
KW - Biofilm
KW - Control
KW - Escherichia coli O157:H7
KW - Phytic acid
KW - Sodium chloride
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U2 - 10.1016/j.ijfoodmicro.2016.03.026
DO - 10.1016/j.ijfoodmicro.2016.03.026
M3 - Article
C2 - 27043385
AN - SCOPUS:84961878063
SN - 0168-1605
VL - 227
SP - 17
EP - 21
JO - International Journal of Food Microbiology
JF - International Journal of Food Microbiology
ER -