Analysis and Modeling of the Variability Associated with UV Inactivation of Escherichia coli in Apple Cider

2000 ◽  
Vol 63 (11) ◽  
pp. 1587-1590 ◽  
Author(s):  
SIOBAIN DUFFY ◽  
JOHN CHUREY ◽  
RANDY W. WOROBO ◽  
DONALD W. SCHAFFNER
Keyword(s):  
Escherichia Coli ◽  
Risk Assessment ◽  
Analysis Data ◽  
Quantitative Risk Assessment ◽  
Logistic Distribution ◽  
Apple Cider ◽  
E Coli ◽  
Log Reduction ◽  
Kolmogorov Smirnov ◽  
Smirnov Test

Raw data from validation studies of UV tubes used for nonthermal pathogen reduction in apple cider underwent comprehensive statistical analysis. Data from each tube that demonstrated at least a 5-log reduction of Escherichia coli ATCC 25922, a surrogate for E. coli O157:H7, in each of three trials were used in the analysis. The within- and between-tube variability was calculated for 70 tubes. The mean log reductions of the tubes fit a Beta distribution (Kolmogorov-Smirnov test, 0.0246), and the between-replicate variability followed a logistic distribution (Kolmogorov-Smirnov test, 0.0305). These two distributions can be used together to model UV cider treatment as part of an overall E. coli O157:H7 in cider risk assessment. Examples of codes from @RISK and Analytica to describe these distributions, such as one would find in a quantitative risk assessment, are included.

Modeling the Survival of Escherichia coli O157:H7 in Apple Cider Using Probability Distribution Functions for Quantitative Risk Assessment

2001 ◽  
Vol 64 (5) ◽  
pp. 599-605 ◽  
Author(s):  
SIOBAIN DUFFY ◽  
DONALD W. SCHAFFNER
Keyword(s):  
Escherichia Coli ◽  
Risk Assessment ◽  
Room Temperature ◽  
Storage Conditions ◽  
Distribution Functions ◽  
Quantitative Risk Assessment ◽  
Escherichia Coli O157 ◽  
Apple Cider ◽  
E Coli ◽  
Probability Distribution Functions

Outbreaks of foodborne illness from apple cider have prompted research on the survival of Escherichia coli O157:H7 in this food. Published results vary widely, potentially due to differences in E. coli O157:H7 strains, enumeration media, and other experimental considerations. We developed probability distribution functions for the change in concentration of E. coli O157:H7 (log CFU/day) in cider using data from scientific publications for use in a quantitative risk assessment. Six storage conditions (refrigeration [4 to 5°C]; temperature abuse [6 to 10°C]; room temperature [20 to 25°C]; refrigerated with 0.1% sodium benzoate, 0.1% potassium sorbate, or both) were modeled. E. coli survival rate data for all three unpreserved cider storage conditions were highly peaked, and these data were fit to logistic distributions: ideal refrigeration, logistic (−0.061, 0.13); temperature abuse, logistic (−0.0982, 0.23); room temperature, logistic (−0.1, 0.29) and uniform (−4.3, −1.8), to model the very small chance of extremely high log CFU reductions. There were fewer published studies on refrigerated, preserved cider, and these smaller data sets were modeled with beta (4.27, 2.37) × 2.2 − 1.6, normal (−0.2, 0.13), and gamma (1.45, 0.6) distributions, respectively. Simulations were run to show the effect of storage on E. coli O157:H7 during the shelf life of apple cider. Under every storage condition, with and without preservatives, there was an overall decline in E. coli O157:H7 populations in cider, although a small fraction of the time a slight increase was seen.

Inactivation of Escherichia coli (ATCC 4157) in Diluted Apple Cider by Dense-Phase Carbon Dioxide

2006 ◽  
Vol 69 (1) ◽  
pp. 12-16 ◽  
Author(s):  
GURBUZ GUNES ◽  
L. K. BLUM ◽  
J. H. HOTCHKISS
Keyword(s):  
Escherichia Coli ◽  
Carbon Dioxide ◽  
High Sensitivity ◽  
Effect Of Temperature ◽  
Dense Phase ◽  
Apple Cider ◽  
E Coli ◽  
Product Ratio ◽  
Log Reduction ◽  
Temperature And Pressure

Dense-phase carbon dioxide (CO2) treatments in a continuous flow through system were applied to apple cider to inactivate Escherichia coli (ATCC 4157). A response surface design with factors of the CO2/product ratio (0, 70, and 140 g/kg), temperature (25, 35, and 45°C), and pressure (6.9, 27.6, and 48.3 MPa) were used. E. coli was very sensitive to dense CO2 treatment, with a more than 6-log reduction in treatments containing 70 and 140 g/kg CO2, irrespective of temperature and pressure. The CO2/product ratio was the most important factor affecting inactivation rate of E. coli. No effect of temperature and pressure was detected because of high sensitivity of the cells to dense CO2. Dense CO2 could be an alternative pasteurization treatment for apple cider. Further studies dealing with the organoleptic quality of the product are needed.

Efficacy of Ultraviolet Light for Reducing Escherichia coli O157:H7 in Unpasteurized Apple Cider

2000 ◽  
Vol 63 (5) ◽  
pp. 563-567 ◽  
Author(s):  
J. R. WRIGHT ◽  
S. S. SUMNER ◽  
C. R. HACKNEY ◽  
M. D. PIERSON ◽  
B. W. ZOECKLEIN
Keyword(s):  
Thin Film ◽  
Escherichia Coli ◽  
Uv Light ◽  
Uv Disinfection ◽  
Escherichia Coli O157 ◽  
Apple Cider ◽  
E Coli ◽  
Log Reduction ◽  
Disinfection Unit ◽  
Additional Reduction

This study examined the efficacy of UV light for reducing Escherichia coli O157:H7 in unpasteurized cider. Cider containing a mixture of acid-resistant E. coli O157:H7 (6.3 log CFU/ml) was treated using a thin-film UV disinfection unit at 254 nm. Dosages ranged from 9,402 to 61,005 μW-s/cm2. Treatment significantly reduced E. coli O157:H7 (P ≤ 0.0001). Mean reduction for all treated samples was 3.81 log CFU/ml. Reduction was also affected by the level of background microflora in cider. Results indicate that UV light is effective for reducing this pathogen in cider. However, with the dosages used in this experiment, additional reduction measures are necessary to achieve the required 5-log reduction.

Validation of Apple Cider Pasteurization Treatments against Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes

2001 ◽  
Vol 64 (11) ◽  
pp. 1679-1689 ◽  
Author(s):  
PEGGY P. MAK ◽  
BARBARA H. INGHAM ◽  
STEVEN C. INGHAM
Keyword(s):  
Escherichia Coli ◽  
New York ◽  
Listeria Monocytogenes ◽  
Fluorescent Protein ◽  
Escherichia Coli O157 ◽  
Salmonella Spp ◽  
Apple Cider ◽  
E Coli ◽  
Log Reduction ◽  
Green Fluorescent

Time and temperature pasteurization conditions common in the Wisconsin cider industry were validated using a six-strain cocktail of Escherichia coli O157:H7 and acid-adapted E. coli O157:H7 in pH- and ∘Brix-adjusted apple cider. Strains employed were linked to outbreaks (ATCC 43894 and 43895, C7927, and USDA-FSIS-380–94) or strains engineered to contain the gene for green fluorescent protein (pGFP ATCC 43894 and pGFP ATCC 43889) for differential enumeration. Survival of Salmonella spp. (CDC 0778, CDC F2833, and CDC HO662) and Listeria monocytogenes (H0222, F8027, and F8369) was also evaluated. Inoculated cider of pH 3.3 or 4.1 and 11 or 14°Brix was heated under conditions ranging from 60°C for 14 s to 71.1°C for 14 s. A 5-log reduction of nonadapted and acid-adapted E. coli O157:H7 was obtained at 68.1°C for 14 s. Lower temperatures, or less time at 68.1°C, did not ensure a 5-log reduction in E. coli O157:H7. A 5-log reduction was obtained at 65.6°C for 14 s for Salmonella spp. L. monocytogenes survived 68.1°C for 14 s, but survivors died in cider within 24 h at 4°C. Laboratory results were validated with a surrogate E. coli using a bench-top plate heat-exchange pasteurizer. Results were further validated using fresh unpasteurized commercial ciders. Consumer acceptance of cider pasteurized at 68.1°C for 14 s (Wisconsin recommendations) and at 71.1°C for 6 s (New York recommendations) was not significantly different. Hence, we conclude that 68.1°C for 14 s is a validated treatment for ensuring adequate destruction of E. coli O157:H7, Salmonella spp., and L. monocytogenes in apple cider.

Escherichia coli O157: H7 Acid Tolerance and Survival in Apple Cider

1994 ◽  
Vol 57 (6) ◽  
pp. 460-464 ◽  
Author(s):  
LESLIE GARLAND MILLER ◽  
CHARLES W. KASPAR
Keyword(s):  
Escherichia Coli ◽  
Sodium Benzoate ◽  
Acid Tolerance ◽  
Potassium Sorbate ◽  
Escherichia Coli O157 ◽  
Control Strain ◽  
High Ph ◽  
Apple Cider ◽  
E Coli ◽  
Log Reduction

The survival of two Escherichia coli O157:H7 (ATCC 43889 and 43895) and a control strain E. coli was compared in apple cider and in Trypticase soy broth (TSB) adjusted to low and high pH. The O157:H7 strains were detectable in apple cider after 14 to 21 days at 4°C, whereas the control strain could not be detected (> 4-log reduction) after 5 to 7 days. During the first 14 days of storage at 4°C, the levels of strain 43889 decreased by ~3 logs, whereas levels of strain 43895 were unchanged. Survival of O157:H7 strains and the control strain were unaffected by the presence of potassium sorbate or sodium benzoate, except in one instance. Sodium benzoate caused a decrease of 57% in strain 43895 after 21 days, but ~104 CFU/ml still remained. In TSB adjusted to pH 2, 3, 4, 11 or 12, strain 43895 was again the more resistant of the O157:H7 strains, both of which were more durable than the control strain. The O157:H7 strains (especially strain 43895) withstood pH 2 with a minimal drop in CPU after 24 h, whereas no viable organisms were detectable after this time at pH 12. At these extremes of pH, survival was generally greater at 4°C than at 25°C. Despite differences between strains, these results show that E. coli O157:H7 is exceptionally tolerant of acid pH.

Antimicrobial Effects of Weak Acids on the Survival of Escherichia coli O157:H7 under Anaerobic Conditions†‡

2011 ◽  
Vol 74 (6) ◽  
pp. 893-898 ◽  
Author(s):  
HUIYING J. LU ◽  
FREDERICK BREIDT ◽  
ILENYS M. PÉREZ-DÍAZ ◽  
JASON A. OSBORNE
Keyword(s):  
Escherichia Coli ◽  
Food Products ◽  
Escherichia Coli O157 ◽  
Weak Acids ◽  
Anaerobic Conditions ◽  
Antimicrobial Effects ◽  
Apple Cider ◽  
E Coli ◽  
Log Reduction ◽  
Antimicrobial Effectiveness

Outbreaks of disease due to vegetative bacterial pathogens associated with acid foods (such as apple cider) have raised concerns about acidified vegetables and related products that have a similar pH (3.2 to 4.0). Escherichia coli O157:H7 and related strains of enterohemorrhagic E. coli (EHEC) have been identified as the most acid resistant vegetative pathogens in these products. Previous research has shown that the lack of dissolved oxygen in many hermetically sealed acid or acidified food products can enhance survival of EHEC compared with their survival under aerobic conditions. We compared the antimicrobial effects of several food acids (acetic, malic, lactic, fumaric, benzoic, and sorbic acids and sulfite) on a cocktail of EHEC strains under conditions representative of non–heat-processed acidified vegetables in hermetically sealed jars, holding the pH (3.2) and ionic strength (0.342) constant under anaerobic conditions. The overall antimicrobial effectiveness of weak acids used in this study was ranked, from most effective to least effective: sulfite > benzoic acid > sorbic acid > fumaric acid > l- and d-lactic acid > acetic acid > malic acid. These rankings were based on the estimated protonated concentrations required to achieve a 5-log reduction in EHEC after 24 h of incubation at 30°C. This study provides information that can be used to formulate safer acid and acidified food products and provides insights about the mode of action of weak acids against EHEC.

Inactivation of Escherichia coli ATCC 25922 and Escherichia coli O157:H7 in Apple Juice and Apple Cider, Using Pulsed Light Treatment

2009 ◽  
Vol 72 (5) ◽  
pp. 937-944 ◽  
Author(s):  
ANNE SAUER ◽  
CARMEN I. MORARU
Keyword(s):  
Escherichia Coli ◽  
Apple Juice ◽  
Most Probable Number ◽  
Inactivation Kinetics ◽  
Pulsed Light ◽  
Static Mode ◽  
Probable Number ◽  
Apple Cider ◽  
E Coli ◽  
Log Reduction

The main objective of this work was to evaluate the effectiveness of pulsed light (PL) treatment for the inactivation of Escherichia coli in liquids with different levels of clarity. Nonpathogenic E. coli ATCC 25922 and pathogenic E. coli O157: H7 were used as challenge organisms. Butterfield's phosphate buffer (BPB), tryptic soy broth (TSB), apple juice, and apple cider were used as substrates. The inoculated liquids were placed in a thin layer (1.3 mm) into glass chambers (23 by 53 by 11 mm) and exposed to PL doses of up to 13.1 J/cm2. PL treatments were performed in a Xenon RS-3000C PL unit, both in static mode and under turbulence. Survivors were determined by standard plate counting or the most-probable-number technique. For static treatments, reduction levels exceeding 8.5 log were obtained in BPB for all strains and reduction levels of about 3.5 log were obtained in TSB. For apple juice, inactivation levels of 2.66 ± 0.10 log were obtained for E. coli ATCC 25922 and 2.52 ± 0.19 log for E. coli O157:H7. In cider, inactivation levels of 2.32 ± 0.16 log and 3.22 ± 0.29 log were obtained for the nonpathogenic and pathogenic strains, respectively. Inactivation kinetics was characterized using the Weibull model. Turbulent treatments resulted in 5.76 ± 0.06 log reduction in cider and 7.15 ± 0.22 log reduction in juice, which satisfies the U.S. Food and Drug Administration requirement of 5-log reduction of E. coli. These results show promise for the use of PL for the effective reduction of E. coli in apple juice and cider.

scholarly journals Influence of Apple Cultivars on Inactivation of Different Strains of Escherichia coli O157:H7 in Apple Cider by UV Irradiation

2004 ◽  
Vol 70 (10) ◽  
pp. 6061-6065 ◽  
Author(s):  
N. Basaran ◽  
A. Quintero-Ramos ◽  
M. M. Moake ◽  
J. J. Churey ◽  
R. W. Worobo
Keyword(s):  
Escherichia Coli ◽  
Uv Irradiation ◽  
Strain Analysis ◽  
Bacterial Populations ◽  
Apple Cider ◽  
E Coli ◽  
Log Reduction ◽  
Disinfection Process ◽  
Apple Cultivars ◽  
Different Strains

ABSTRACT This study examined the effect of different apple cultivars upon the UV inactivation of Escherichia coli O157:H7 strains within unfiltered apple cider. Apple cider was prepared from eight different apple cultivars, inoculated with approximately 106 to 107 CFU of three strains of E. coli O157:H7 per ml (933, ATCC 43889, and ATCC 43895), and exposed to 14 mJ of UV irradiation per cm2. Bacterial populations for treated and untreated samples were then enumerated by using nonselective media. E. coli O157:H7 ATCC 43889 showed the most sensitivity to this disinfection process with an average 6.63-log reduction compared to an average log reduction of 5.93 for both strains 933 and ATCC 43895. The highest log reduction seen, 7.19, occurred for strain ATCC 43889 in Rome cider. The same cider produced the lowest log reductions: 5.33 and 5.25 for strains 933 and ATCC 43895, respectively. Among the apple cultivars, an average log reduction range of 5.78 (Red Delicious) to 6.74 (Empire) was observed, with two statistically significant (α ≤ 0.05) log reduction groups represented. Within the paired cultivar-strain analysis, five of eight ciders showed statistically significant (α ≤ 0.05) differences in at least two of the E. coli strains used. Comparison of log reductions among the E. coli strains to the cider parameters of °Brix, pH, and malic acid content failed to show any statistically significant relationship (R 2 ≥ 0.95). However, the results of this study indicate that regardless of the apple cultivar used, a minimum 5-log reduction is achieved for all of the strains of E. coli O157:H7 tested.

Modeling of Escherichia coli Inactivation by UV Irradiation at Different pH Values in Apple Cider

2004 ◽  
Vol 67 (6) ◽  
pp. 1153-1156 ◽  
Author(s):  
A. QUINTERO-RAMOS ◽  
J. J. CHUREY ◽  
P. HARTMAN ◽  
J. BARNARD ◽  
R. W. WOROBO
Keyword(s):  
Escherichia Coli ◽  
Uv Irradiation ◽  
Uv Light ◽  
Reduction Factor ◽  
Attractive Alternative ◽  
Bacterial Populations ◽  
Apple Cider ◽  
E Coli ◽  
Log Reduction ◽  
Uv Dose

This study examined the effects and interactions of UV light dose (1,800 to 20,331 μJ/cm2) and apple cider pH (2.99 to 4.41) on the inactivation of Escherichia coli ATCC 25922, a surrogate for E. coli O157:H7. A predictive model was developed to relate the log reduction factor of E. coli ATCC 25922 to the UV dose. Bacterial populations for treated and untreated samples were enumerated with the use of nonselective media. The results revealed that UV dose was highly significant in the inactivation of E. coli, whereas pH showed no significant effect at higher UV doses. Doses of 6,500 μJ/cm2 or more were sufficient to achieve a greater than 5-log reduction of E. coli. Experimental inactivation data were fitted adequately by a logistic regression model. UV irradiation is an attractive alternative to conventional methods for reducing bacteria in unpasteurized apple cider.

Addition of Fumaric Acid and Sodium Benzoate as an Alternative Method To Achieve a 5-log Reduction of Escherichia coli O157:H7 Populations in Apple Cider

2002 ◽  
Vol 65 (3) ◽  
pp. 476-483 ◽  
Author(s):  
JUSTIN E. COMES ◽  
ROBERT B. BEELMAN
Keyword(s):  
Escherichia Coli ◽  
Fumaric Acid ◽  
Sodium Benzoate ◽  
Bactericidal Effect ◽  
Escherichia Coli O157 ◽  
Refrigerated Storage ◽  
Apple Cider ◽  
E Coli ◽  
Log Reduction ◽  
Strong Linear Correlation

A study was conducted to develop a preservative treatment capable of the Food and Drug Administration–mandated 5-log reduction of Escherichia coli O157:H7 populations in apple cider. Unpreserved apple cider was treated with generally recognized as safe acidulants and preservatives before inoculation with E. coli O157:H7 in test tubes and subjected to mild heat treatments (25, 35, and 45°C) followed by refrigerated storage (4°C). Fumaric acid had significant (P < 0.05) bactericidal effect when added to cider at 0.10% (wt/vol) and adjusted to pH 3.3, but citric and malic acid had no effect. Strong linear correlation (R2 = 0.96) between increasing undissociated fumaric acid concentrations and increasing log reductions of E. coli O157:H7 in apple cider indicated the undissociated acid to be the bactericidal form. The treatment that achieved the 5-log reduction in three commercial ciders was the addition of fumaric acid (0.15%, wt/vol) and sodium benzoate (0.05%, wt/vol) followed by holding at 25°C for 6 h before 24 h of refrigeration at 4°C. Subsequent experiments revealed that the same preservatives added to cider in flasks resulted in a more than 5-log reduction in less than 5 and 2 h when held at 25 and 35°C, respectively. The treatment also significantly (P < 0.05) reduced total aerobic counts in commercial ciders to populations less than those of pasteurized and raw ciders from the same source (after 5 and 21 days of refrigerated storage at 4°C, respectively). Sensory evaluation of the same ciders revealed that consumers found the preservative-treated cider to be acceptable.

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