Optimization of low-temperature blanching combined with calcium treatment to inactivate Escherichia coli O157:H7 on fresh-cut spinach

N. H. Kim; N. Y. Lee; S. H. Kim; H. J. Lee; Y. Kim; J. H. Ryu; M. S. Rhee

doi:10.1111/jam.12815

Optimization of low-temperature blanching combined with calcium treatment to inactivate Escherichia coli O157:H7 on fresh-cut spinach

N. H. Kim, N. Y. Lee, S. H. Kim, H. J. Lee, Y. Kim, J. H. Ryu, M. S. Rhee

Department of Biotechnology

Research output: Contribution to journal › Article › peer-review

6 Citations (Scopus)

Abstract

Aims: To develop a mild blanching method with calcium salts to ensure microbiological safety and quality of fresh-cut spinach. Methods and Results: The antimicrobial efficacy of eight calcium salts was evaluated on Escherichia coli O157:H7 at 45-65°C and calcium hydroxide (Ca(OH)₂) showed the greatest synergistic antimicrobial effect with heat. Combinations of low temperature treatments (45, 55, 65°C), time (20, 40, 60 s) and Ca(OH)₂ (0·25, 0·50, 0·75%) were applied for E. coli O157:H7 disinfection on fresh-cut spinach to develop a predictive model using a Box-Behnken experimental design. A suitable quadratic model was produced (R² = 0·98, P < 0·001) and the optimum condition (64·9°C with 0·52% Ca(OH)₂ for 42·4 s) was drawn by reducing 6·6 log CFU g^-1 of E. coli O157:H7 on fresh-cut spinach. Blanching at 61·9°C with 0·52% Ca(OH)₂ for 41·7 s can inactivate E. coli O157:H7 on spinach by 5·4 log CFU g^-1. The new method was comparable to the CDC recommendation for safe spinach cooking (71·1°C, 15 s; 5·0 log CFU g^-1 reduction) with lower levels of weight loss of the spinach (P < 0·05). Conclusions: This study suggests an efficient spinach blanching method for E. coli O157:H7 disinfection. Significance and Impact of the Study: This blanching method will enhance microbiological safety of fresh-cut produce while minimizing the use of energy and chemicals.

Original language	English
Pages (from-to)	139-148
Number of pages	10
Journal	Journal of Applied Microbiology
Volume	119
Issue number	1
DOIs	https://doi.org/10.1111/jam.12815
Publication status	Published - 2015 Jul 1

Keywords

Antimicrobials
EHEC (enterohaemorrhagic E. coli)
Food safety
Infection
Postharvest

ASJC Scopus subject areas

Biotechnology
Applied Microbiology and Biotechnology

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10.1111/jam.12815

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title = "Optimization of low-temperature blanching combined with calcium treatment to inactivate Escherichia coli O157:H7 on fresh-cut spinach",

abstract = "Aims: To develop a mild blanching method with calcium salts to ensure microbiological safety and quality of fresh-cut spinach. Methods and Results: The antimicrobial efficacy of eight calcium salts was evaluated on Escherichia coli O157:H7 at 45-65°C and calcium hydroxide (Ca(OH)2) showed the greatest synergistic antimicrobial effect with heat. Combinations of low temperature treatments (45, 55, 65°C), time (20, 40, 60 s) and Ca(OH)2 (0·25, 0·50, 0·75%) were applied for E. coli O157:H7 disinfection on fresh-cut spinach to develop a predictive model using a Box-Behnken experimental design. A suitable quadratic model was produced (R2 = 0·98, P < 0·001) and the optimum condition (64·9°C with 0·52% Ca(OH)2 for 42·4 s) was drawn by reducing 6·6 log CFU g-1 of E. coli O157:H7 on fresh-cut spinach. Blanching at 61·9°C with 0·52% Ca(OH)2 for 41·7 s can inactivate E. coli O157:H7 on spinach by 5·4 log CFU g-1. The new method was comparable to the CDC recommendation for safe spinach cooking (71·1°C, 15 s; 5·0 log CFU g-1 reduction) with lower levels of weight loss of the spinach (P < 0·05). Conclusions: This study suggests an efficient spinach blanching method for E. coli O157:H7 disinfection. Significance and Impact of the Study: This blanching method will enhance microbiological safety of fresh-cut produce while minimizing the use of energy and chemicals.",

keywords = "Antimicrobials, EHEC (enterohaemorrhagic E. coli), Food safety, Infection, Postharvest",

author = "Kim, {N. H.} and Lee, {N. Y.} and Kim, {S. H.} and Lee, {H. J.} and Y. Kim and Ryu, {J. H.} and Rhee, {M. S.}",

note = "Publisher Copyright: {\textcopyright} 2015 The Society for Applied Microbiology.",

year = "2015",

month = jul,

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doi = "10.1111/jam.12815",

language = "English",

volume = "119",

pages = "139--148",

journal = "Proceedings of the Society for Applied Bacteriology",

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T1 - Optimization of low-temperature blanching combined with calcium treatment to inactivate Escherichia coli O157:H7 on fresh-cut spinach

AU - Kim, N. H.

AU - Lee, N. Y.

AU - Kim, S. H.

AU - Lee, H. J.

AU - Kim, Y.

AU - Ryu, J. H.

AU - Rhee, M. S.

PY - 2015/7/1

Y1 - 2015/7/1

N2 - Aims: To develop a mild blanching method with calcium salts to ensure microbiological safety and quality of fresh-cut spinach. Methods and Results: The antimicrobial efficacy of eight calcium salts was evaluated on Escherichia coli O157:H7 at 45-65°C and calcium hydroxide (Ca(OH)2) showed the greatest synergistic antimicrobial effect with heat. Combinations of low temperature treatments (45, 55, 65°C), time (20, 40, 60 s) and Ca(OH)2 (0·25, 0·50, 0·75%) were applied for E. coli O157:H7 disinfection on fresh-cut spinach to develop a predictive model using a Box-Behnken experimental design. A suitable quadratic model was produced (R2 = 0·98, P < 0·001) and the optimum condition (64·9°C with 0·52% Ca(OH)2 for 42·4 s) was drawn by reducing 6·6 log CFU g-1 of E. coli O157:H7 on fresh-cut spinach. Blanching at 61·9°C with 0·52% Ca(OH)2 for 41·7 s can inactivate E. coli O157:H7 on spinach by 5·4 log CFU g-1. The new method was comparable to the CDC recommendation for safe spinach cooking (71·1°C, 15 s; 5·0 log CFU g-1 reduction) with lower levels of weight loss of the spinach (P < 0·05). Conclusions: This study suggests an efficient spinach blanching method for E. coli O157:H7 disinfection. Significance and Impact of the Study: This blanching method will enhance microbiological safety of fresh-cut produce while minimizing the use of energy and chemicals.

AB - Aims: To develop a mild blanching method with calcium salts to ensure microbiological safety and quality of fresh-cut spinach. Methods and Results: The antimicrobial efficacy of eight calcium salts was evaluated on Escherichia coli O157:H7 at 45-65°C and calcium hydroxide (Ca(OH)2) showed the greatest synergistic antimicrobial effect with heat. Combinations of low temperature treatments (45, 55, 65°C), time (20, 40, 60 s) and Ca(OH)2 (0·25, 0·50, 0·75%) were applied for E. coli O157:H7 disinfection on fresh-cut spinach to develop a predictive model using a Box-Behnken experimental design. A suitable quadratic model was produced (R2 = 0·98, P < 0·001) and the optimum condition (64·9°C with 0·52% Ca(OH)2 for 42·4 s) was drawn by reducing 6·6 log CFU g-1 of E. coli O157:H7 on fresh-cut spinach. Blanching at 61·9°C with 0·52% Ca(OH)2 for 41·7 s can inactivate E. coli O157:H7 on spinach by 5·4 log CFU g-1. The new method was comparable to the CDC recommendation for safe spinach cooking (71·1°C, 15 s; 5·0 log CFU g-1 reduction) with lower levels of weight loss of the spinach (P < 0·05). Conclusions: This study suggests an efficient spinach blanching method for E. coli O157:H7 disinfection. Significance and Impact of the Study: This blanching method will enhance microbiological safety of fresh-cut produce while minimizing the use of energy and chemicals.

KW - Antimicrobials

KW - EHEC (enterohaemorrhagic E. coli)

KW - Food safety

KW - Infection

KW - Postharvest

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U2 - 10.1111/jam.12815

DO - 10.1111/jam.12815

M3 - Article

C2 - 25816844

AN - SCOPUS:84931573503

SN - 1364-5072

VL - 119

SP - 139

EP - 148

JO - Proceedings of the Society for Applied Bacteriology

JF - Proceedings of the Society for Applied Bacteriology

IS - 1

ER -

Optimization of low-temperature blanching combined with calcium treatment to inactivate Escherichia coli O157:H7 on fresh-cut spinach

Abstract

Keywords

ASJC Scopus subject areas

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