TY - JOUR
T1 - Use of phytic acid and hyper-salting to eliminate Escherichia coli O157
T2 - H7 from napa cabbage for kimchi production in a commercial plant
AU - Kim, Nam Hee
AU - Jang, Seong Ho
AU - Kim, Soon Han
AU - Lee, Hee Jung
AU - Kim, Younghoon
AU - Ryu, Jee Hoon
AU - Rhee, Min Suk
N1 - Funding Information:
This study was supported by a grant (# 13162MFDS045 ) from the Korea Ministry of Food and Drug Safety (2013–2014) and a Korea University Grant . The authors thank the Institute of Biomedical Science and Food Safety, Korea University Food Safety Hall, for providing the equipment and facilities.
Publisher Copyright:
© 2015 Elsevier B.V.
PY - 2015/12/2
Y1 - 2015/12/2
N2 - The aim of this study was to develop a new salting method using natural phytic acid (PA) to ensure the microbiological safety and quality of salted napa cabbage used for kimchi production. The production of salted napa cabbage involves several stages: trimming, hyper-salting (20% NaCl) for up to 1. h, salting (10% NaCl for 10-18. h), three sequential washes in water (30. s for each), and draining (2. h). Two separate experiments were performed: one to determine the appropriate treatment conditions and a second to validate applicability under commercial conditions. In Experiment I, the effects of hyper-salting with PA on Escherichia coli O157:H7 numbers were tested in the laboratory. The following variables were monitored: 1) PA concentration (1, 2, 3%, w/w); 2) the ratio of the sample weight to the total volume of the solution (1:1.5, 1:3, or 1:6); 3) the hyper-salting time (30 or 60 min); and 4) the salting time (2, 5, or 8. h). A procedure that achieved a >. 5-log reduction in the E. coli O157:H7 population was then tested in an actual kimchi processing plant (Experiment II). The results from Experiment I showed that bactericidal efficacy increased as all the measured variables increased (p< 0.05). Hyper-salting with 2% PA at a sample-to-water ratio (w/v) of 1:3 and 1:6 for 60. min resulted in a >. 5-log. CFU/g reduction in the E. coli O157:H7 population. Further salting for 5. h completely eliminated (< 1-log. CFU/g) all bacteria. Thus, hyper-salting with PA 2% at a sample-to-water ratio of 1:3 for 60. min, followed by salting for 5. h, was tested under large-scale production conditions. The results revealed that the initial aerobic plate counts (APC), total coliform counts (TC), and fecal coliform counts (FC) were 6.6, 3.4, and 2.8-log. CFU/g, respectively. The selected protocol reduced these values by 3.7-, >. 2.4-, and >. 1.8-log. CFU/g, respectively. The 5. h salting step maintained the TC and FC at < 1-log. CFU/g; however, the APC recovered somewhat. The pH and salinity of the treated salted napa cabbages were within the ranges required for kimchi production (pH. 5.1-5.3 and 1.5-2.0%, respectively). These results suggest that this novel method of salting food ensures microbiological safety and reduces the production time.
AB - The aim of this study was to develop a new salting method using natural phytic acid (PA) to ensure the microbiological safety and quality of salted napa cabbage used for kimchi production. The production of salted napa cabbage involves several stages: trimming, hyper-salting (20% NaCl) for up to 1. h, salting (10% NaCl for 10-18. h), three sequential washes in water (30. s for each), and draining (2. h). Two separate experiments were performed: one to determine the appropriate treatment conditions and a second to validate applicability under commercial conditions. In Experiment I, the effects of hyper-salting with PA on Escherichia coli O157:H7 numbers were tested in the laboratory. The following variables were monitored: 1) PA concentration (1, 2, 3%, w/w); 2) the ratio of the sample weight to the total volume of the solution (1:1.5, 1:3, or 1:6); 3) the hyper-salting time (30 or 60 min); and 4) the salting time (2, 5, or 8. h). A procedure that achieved a >. 5-log reduction in the E. coli O157:H7 population was then tested in an actual kimchi processing plant (Experiment II). The results from Experiment I showed that bactericidal efficacy increased as all the measured variables increased (p< 0.05). Hyper-salting with 2% PA at a sample-to-water ratio (w/v) of 1:3 and 1:6 for 60. min resulted in a >. 5-log. CFU/g reduction in the E. coli O157:H7 population. Further salting for 5. h completely eliminated (< 1-log. CFU/g) all bacteria. Thus, hyper-salting with PA 2% at a sample-to-water ratio of 1:3 for 60. min, followed by salting for 5. h, was tested under large-scale production conditions. The results revealed that the initial aerobic plate counts (APC), total coliform counts (TC), and fecal coliform counts (FC) were 6.6, 3.4, and 2.8-log. CFU/g, respectively. The selected protocol reduced these values by 3.7-, >. 2.4-, and >. 1.8-log. CFU/g, respectively. The 5. h salting step maintained the TC and FC at < 1-log. CFU/g; however, the APC recovered somewhat. The pH and salinity of the treated salted napa cabbages were within the ranges required for kimchi production (pH. 5.1-5.3 and 1.5-2.0%, respectively). These results suggest that this novel method of salting food ensures microbiological safety and reduces the production time.
KW - Disinfection
KW - Escherichia coli O157:H7
KW - Phytic acid
KW - Salted napa cabbage
KW - Sodium chloride
UR - http://www.scopus.com/inward/record.url?scp=84937807885&partnerID=8YFLogxK
U2 - 10.1016/j.ijfoodmicro.2015.07.024
DO - 10.1016/j.ijfoodmicro.2015.07.024
M3 - Article
C2 - 26210534
AN - SCOPUS:84937807885
VL - 214
SP - 24
EP - 30
JO - International Journal of Food Microbiology
JF - International Journal of Food Microbiology
SN - 0168-1605
ER -