Inactivation efficacies of lactic acid and mild heat treatments against Escherichia coli strains in organic broccoli sprouts

Food Control ◽  
2021 ◽  
pp. 108577
Author(s):  
Lin Chen ◽  
Qin Liu ◽  
Xue Zhao ◽  
Hongfei Zhang ◽  
Xinyi Pang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Lactic Acid ◽  
Heat Treatments ◽  
Broccoli Sprouts ◽  
Mild Heat

scholarly journals Control of Autochthonous Spoilage Lactic Acid Bacteria in Apple and Orange Juices by Sensorially Accepted Doses of Citrus Spp. Essential Oils Combined with Mild Heat Treatments

2019 ◽  
Vol 84 (4) ◽  
pp. 848-858 ◽  
Author(s):  
Geany Targino Souza Pedrosa ◽  
Rayssa Julliane Carvalho ◽  
Daniel Berdejo ◽  
Evandro Leite Souza ◽  
Rafael Pagán ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Essential Oils ◽  
Heat Treatments ◽  
Mild Heat ◽  
Citrus Spp

Efficacy of UV, Acidified Sodium Hypochlorite, and Mild Heat for Decontamination of Surface and Infiltrated Escherichia coli O157:H7 on Green Onions and Baby Spinach

2012 ◽  
Vol 75 (7) ◽  
pp. 1198-1206 ◽  
Author(s):  
M. ZEKI DURAK ◽  
JOHN J. CHUREY ◽  
RANDY W. WOROBO
Keyword(s):  
Escherichia Coli ◽  
Sodium Hypochlorite ◽  
Fresh Produce ◽  
Combined Treatment ◽  
Heat Treatments ◽  
Contamination Level ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Mild Heat ◽  
The Individual

Produce-associated foodborne illnesses outbreaks have highlighted the need for more effective decontamination methods to ensure the safety of fresh produce. The main objective of this study was to evaluate the individual and combined efficacies of germicidal UV light (12.5 to 500 mJ/cm2), acidified sodium hypochlorite (ASC; 10 to 200 ppm), and mild heat (40 to 50°C) for decontaminating green onions and baby spinach infected with Escherichia coli O157:H7. Samples were inoculated by spot and dip inoculation methods to mimic surface and infiltrated E. coli O157:H7 contamination, respectively. In green onions and baby spinach, the individual efficacies of UV, ASC, and mild-heat treatments varied based on the produce type and contamination method. Following analysis of the efficacies of the single treatments, a combined treatment with 125 mJ/cm2 UV and 200 ppm of ASC at 50°C was selected for spot-inoculated green onions, and a combined treatment with 125 mJ/cm2 UV and 200 ppm of ASC at 20°C was selected for spot- and dip-inoculated baby spinach. While a >5-log reduction was achieved with the combination treatment for spot-inoculated green onions with an initial contamination level of 7.2 log CFU per spot, the same treatment reduced E. coli O157:H7 populations below the detection limit (<1 log) on green onions spot inoculated at a lower contamination level (4.3 log CFU per spot). On spot- and dip-inoculated baby spinach, the combined treatment reduced E. coli O157:H7 populations by 2.8 log CFU per spot and 2.6 log CFU/g, respectively. The combined treatment of 500 mJ/cm2 UV and 200 ppm of ASC at 50°C selected for the decontamination of dip-inoculated green onions resulted in a 2.2-log CFU/g reduction. These findings suggest that when foodborne pathogens contaminate produce and subsequently infiltrate, attach to, or become localized into protected areas, the individual or combined applications of UV, ASC, and mild-heat treatments have limited decontamination efficacies on both green onions and baby spinach (<3 log). However, treatments combining UV, ASC, and mild heat could be a promising application for reducing pathogen populations (>5 log) on E. coli O157:H7 surface-contaminated green onions. This study also highlights the importance of developing and optimizing produce-specific decontamination methods to ensure the safety of fresh produce commodities.

Influence of Cinnamon and Clove Essential Oils on the D - and z-Values of Escherichia coli O157:H7 in Apple Cider

2007 ◽  
Vol 70 (9) ◽  
pp. 2089-2094 ◽  
Author(s):  
K. P. KNIGHT ◽  
R. C. McKELLAR
Keyword(s):  
Escherichia Coli ◽  
Synergistic Effect ◽  
Essential Oils ◽  
Heat Treatments ◽  
Moderate Activity ◽  
Escherichia Coli O157 ◽  
Acidic Ph ◽  
Apple Cider ◽  
E Coli ◽  
Mild Heat

Escherichia coli O157:H7 has become a concern within the apple cider industry. The purpose of this study was to screen several essential oils and isolated components for antimicrobial activity against E. coli O157:H7 in tryptic soy broth at neutral and acidic pH and to assess the effect of these additives on the D-value of E. coli O157:H7 in apple cider in combination with mild heat treatments. Cinnamon oil and clove oil strongly inhibited the growth of E. coli O157:H7 at neutral and acidic pH, (R)-(−)-carvone and (S)-(−)-perillaldehyde were moderately inhibitory at both pH 7.2 and pH 4.5, and citral and geraniol displayed moderate activity at pH 4.5 only. Lemon oil, methyl jasmonate, and p-anisaldehyde displayed little or no antibacterial activity. A synergistic effect between the essential oils and the lower pH of the growth medium was evident by consistently lower MICs at pH 4.5. Cinnamon and clove oils (0.01%, vol/vol) were further tested in apple cider in combination with mild heat treatments for the practical control of E. coli O157:H7 in apple cider. The addition of either essential oil resulted in lower D-values than those for cider alone, suggesting a synergistic effect and the potential efficacy of a mild heat treatment for apple cider.

In Vitro Inhibition of the Growth of Salmonella typhimurium and Escherichia coli 0157:H7 by Bacteria Isolated from the Cecal Contents of Adult Chickens

1991 ◽  
Vol 54 (7) ◽  
pp. 496-501 ◽  
Author(s):  
ARTHUR HINTON ◽  
GEORGE E. SPATES ◽  
DONALD E. CORRIER ◽  
MICHAEL E. HUME ◽  
JOHN R. DELOACH ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Lactic Acid ◽  
Salmonella Typhimurium ◽  
Mixed Cultures ◽  
Enterococcus Durans ◽  
E Coli ◽  
Pure Cultures ◽  
In Vitro Inhibition ◽  
Lactic Acids

A Veillonella species and Enterococcus durans were isolated from the cecal contents of adult broilers. Mixed cultures of Veillonella and E. durans inhibited the growth of Salmonella typhimurium and Escherichia coli 0157:H7 on media containing 2.5% lactose (w/v). The growth of S. typhimurium or E. coli 0157:H7 was not inhibited by mixed cultures containing Veillonella and E. durans on media containing only 0.25% lactose or by pure cultures of Veillonella or E. durans on media containing either 0.25% or 2.5% lactose. The mixed cultures of Veillonella and E. durans produced significantly (P<0.05) more acetic, propionic, and lactic acids in media containing 2.5% lactose than in media containing 0.25% lactose. The inhibition of the enteropathogens was related to the production of lactic acid from lactose by the E. durans and the production of acetic and propionic acids from lactic acid by the Veillonella.

Irradiation D-Values for Escherichia coli O157:H7 and Salmonella sp. on Inoculated Broccoli Seeds and Effects of Irradiation on Broccoli Sprout Keeping Quality and Seed Viability†

2003 ◽  
Vol 66 (5) ◽  
pp. 760-766 ◽  
Author(s):  
KATHLEEN T. RAJKOWSKI ◽  
GLEN BOYD ◽  
DONALD W. THAYER
Keyword(s):  
Escherichia Coli ◽  
Shelf Life ◽  
Dose Level ◽  
Germination Percentage ◽  
Yield Ratio ◽  
Escherichia Coli O157 ◽  
Broccoli Sprouts ◽  
Sprout Length ◽  
D Values ◽  
Irradiation Process

Like alfalfa sprouts, broccoli sprouts can be a vehicle for bacterial pathogens, which can cause illness when they are consumed. The gamma irradiation process was used to reduce numbers of bacterial pathogens on broccoli sprouts and seeds, and the effect of this process on the seeds was studied. The irradiation destruct values for Salmonella sp. and for strains of Escherichia coli O157:H7 inoculated on broccoli seeds were determined. Results obtained in this study indicate that a dose of 2 kGy reduced total background counts for broccoli sprouts from 106 to 107 CFU/g to 104 to 105 CFU/g and increased the shelf life of the sprouts by 10 days. Yield ratio (wt/wt), germination percentage, sprout length, and thickness were measured to determine the effects of various irradiation doses on the broccoli seeds. Results show a decreased germination percentage at a dose level of 4 kGy, whereas the yield ratio (wt/wt), sprout length, and thickness decreased at the 2-kGy dose level. The radiation doses required to inactivate Salmonella sp. and strains of E. coli O157:H7 were higher than previously reported values. D-values, dose required for a 1-log reduction, for the nonvegetable and vegetable Salmonella sp. isolates were 0.74 and 1.10 kGy, respectively. The values for the nonvegetable and vegetable isolated strains of Escherichia coli O157:H7 were 1.43 and 1.11 kGy, respectively. With the irradiation process, a dose of up to 2 kGy can extend the shelf life of broccoli sprouts. A dose of >2 kGy would have an adverse effect on the broccoli seed and decrease the yield of broccoli sprouts.

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