Survival of Escherichia coli O157:H7 and Salmonella in apple cider and orange juice as affected by ozone and treatment temperature

Inactivation of Escherichia coli O157:H7 and Salmonella in apple cider and orange juice treated with ozone was evaluated. A five-strain mixture of E. coli O157:H7 or a five-serovar mixture of Salmonella was inoculated (7 log CFU/ml) into apple cider and orange juice. Ozone (0.9 g/h) was pumped into juices maintained at 4 degrees C, ambient temperature (approximately 20 degrees C), and 50 degrees C for up to 240 min, depending on organism, juice, and treatment temperature. Samples were withdrawn, diluted in 0.1% peptone water, and surface plated onto recovery media. Recovery of E. coli O157:H7 was compared on tryptic soy agar (TSA), sorbitol MacConkey agar, hemorrhagic coli agar, and modified eosin methylene blue agar; recovery of Salmonella was compared on TSA, bismuth sulfite agar, and xylose lysine tergitol 4 (XLT4) agar. After treatment at 50 degrees C, E. coli O157:H7 populations were undetectable (limit of 1.0 log CFU/ml; a minimum 6.0-log CFU/ml reduction) after 45 min in apple cider and 75 min in orange juice. At 50 degrees C, Salmonella was reduced by 4.8 log CFU/ml (apple cider) and was undetectable in orange juice after 15 min. E. coli O157:H7 at 4 degrees C was reduced by 4.8 log CFU/ml in apple cider and by 5.4 log CFU/ml in orange juice. Salmonella was reduced by 4.5 log CFU/ml (apple cider) and 4.2 log CFU/ml (orange juice) at 4 degrees C. Treatment at ambient temperature resulted in population reductions of less than 5.0 log CFU/ml. Recovery of E. coli O157:H7 and Salmonella on selective media was substantially lower than recovery on TSA, indicating development of sublethal injury. Ozone treatment of apple cider and orange juice at 4 degrees C or in combination with mild heating (50 degrees C) may provide an alternative to thermal pasteurization for reduction of E. coli O157:H7 and Salmonella in apple cider and orange juice.     

Influence of cinnamon and clove essential oils on the D- and z-values of Escherichia coli O157:H7 in apple cider

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.     

HEAT INACTIVATION OF ESCHERICHIA COLI 0157:H7 IN APPLE CIDER IN THE PRESENCE OF GLYCEROL MONOLAURATE AND A SYNTHETIC ANTIMICROBIAL PEPTIDE, PR-26

The effect of moderate temperatures in combination with glycerol monolaurate and an antimicrobial peptide, PR-26 on E. coli 0157:H7 in apple cider was determined. A five-strain mixture of E. coli 0157:H7 was inoculated into apple cider (pH 3.53) containing 0.01% PR-26 or 0.02% glycerol monolaurate or a combination of 0.01% PR-26 and 0.02% glycerol monolaurate. The apple cider was incubated at 40, 45 or 50C for 30 s, 5 min, 10 min, and 15 min. At each of the specified time intervals, the surviving population of E. coli 0157:H7 was determined. At all the three temperatures, there was no significant difference (P > 0.05) between the E. coli 0157:H7 populations of the control and the treatment containing PR-26. However, the treatments containing glycerol monolaurate alone or combination of glycerol monolaurate and PR-26 resulted in significant reductions (P < 0.05) in E. coli 0157:H7 counts. Results indicate that addition of glycerol monolaurate (0.02%) to apple cider and heating at 50C for 5 min can reduce E. coli 0157:H7 by 5.0 log CFU/mL.     

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

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 degrees C) followed by refrigerated storage (4 degrees 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 degrees C for 6 h before 24 h of refrigeration at 4 degrees 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 degrees 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 degrees C, respectively). Sensory evaluation of the same ciders revealed that consumers found the preservative-treated cider to be acceptable.     

Verifying apple cider plant sanitation and hazard analysis critical control point programs: choice of indicator bacteria and testing methods.

The objectives of this study were (i) to evaluate the survival of coliforms, Escherichia coli, and enterococci in refrigerated apple cider; (ii) to develop simple and inexpensive presumptive methods for detection of these bacteria; (iii) to perform a field survey to determine the prevalence of these bacteria on apples and in apple cider; and (iv) based on our results, to recommend the most useful of these three indicator groups for use in verifying apple cider processing plant sanitation and hazard analysis critical control point (HACCP) programs. Eight of 10 coliform strains (5 E. coli, 1 Enterobacter aerogenes, and 2 Klebsiella spp.) inoculated into preservative-free apple cider (pH 3.4, 13.3(o) Brix) survived well at 4 degrees C for 6 days (< or = 3.0 log10 CFU/ml decrease). Of 21 enterococci strains (Enterococcus faecalis, E. faecium, and E. durans), only 2 E. durans and 3 E. faecium strains survived well. Simple broth-based colorimetric methods were developed that detected the presence of approximately 10 cells of coliforms or enterococci. In three field studies, samples of unwashed apples (drops and picked), washed apples, and freshly pressed cider were presumptively analyzed for total coliforms, E. coli, and enterococci using qualitative and/or quantitative methods. Drop apples were more likely than picked apples to be contaminated with E. coli (26.7% vs. 0%) and enterococci (20% vs. 0%). Washing had little effect on coliform populations and in one field study was associated with increased numbers. Total coliform populations in cider ranged from < 1 CFU/ml to > 738 most probable number/ml, depending on the enumeration method used and the sample origin. E. coli was not recovered from washed apples or cider, but enterococci were present on 13% of washed apple samples. The qualitative coliform method successfully detected these bacteria on apples and in cider. Based on its exclusively fecal origin, good survival in apple cider, and association with drop apples, we conclude that E. coli is the most useful organism for verifying apple cider sanitation and HACCP programs.     

Inactivation of Escherichia coli inoculated into cloudy apple juice exposed to dense phase carbon dioxide

The inactivation of Escherichia coli in cloudy apple juice by dense phase carbon dioxide (DPCD) was investigated. With CO2 at 20 MPa and 37 degrees C or at 30 MPa and 42 degrees C, the inactivation of E. coli significantly increased (p<0.05) when increasing the exposure time, which conformed to a fast-to-slow two-stage kinetics. The two stages were well fitted to first-order reactions. Higher temperature or pressure significantly enhanced the bactericidal effect of DPCD (p<0.05), the maximum reduction was 7.66 log CFU at 45 MPa and 52 degrees C for 30 min. The survival curves against temperature or pressure were fitted using a linear equation with high regression coefficients (R2>0.94). The temperature inactivation rate (kT) and pressure inactivation rate (kP) were obtained. Higher kT or kP indicated higher susceptibility of E. coli to temperature or pressure. Moreover, there was good linear correlation of kT with pressure (R2=1.00). Also, kP increased with increasing temperature except for 37 degrees C. Greater inactivation of E. coli was obtained with 99.9% CO2 than with 99.5% CO2 or with the initial number of 10(5) CFU/mL than with that of 10(8) CFU/mL at 20 MPa and 37 degrees C.     

INACTIVATION OF E. COLI 0157:H7 IN APPLE CIDER BY OZONE AT VARIOUS TEMPERATURES AND CONCENTRATIONS

The effect of temperature (5–20C) at 860 ppm (v/v) ozone and different gaseous ozone concentrations above 1,000 ppm on inactivation of E. coli O157:H7 in apple cider was studied. Lag times ranged from 3.5 min at 20C to 6.7 min at 10C before the on-set of E. coli O157:H7 inactivation. D-values ranged from 0.6 to 1.5 min at 20C and 5C, respectively. After ozone treatment of cider for 14 min, dissipation of ozone from cider was slow, decreasing to about 5 mg/L after 2 h at 5C. At high gaseous ozone concentration, log time was shortest and D-value lowest. There was a critical concentration of dissolved ozone of about 5–6 mg/L at 20C, before the on-set of E. coli O157:H7 inactivation in the cider. Total processing times, based on lag time plus 5D, ranged from about 4 to 14 min depending on temperature and ozone concentration. Overall, inactivation of E. coli O157:H7 by ozone was fast enough to allow practical applications in cider production, and it should be considered as an alternative to thermal pasteurization.     

Pathogen reduction in unpasteurized apple cider: adding cranberry juice to enhance the lethality of warm hold and freeze-thaw steps

U.S. Food and Drug Administration (FDA) regulations require processors of apple cider sold wholesale to use processing steps that ensure a 5-log reduction in numbers of the pertinent pathogen, generally considered to be Escherichia coli O157:H7. Current widely used validated pathogen-reduction steps are thermal pasteurization and UV light treatment. These techniques may be unaffordable or undesirable for some processors. This study investigated the cran-cider process, which is the addition of cranberry juice at a 15% (vol/vol) level, followed by warm hold (45 degrees C for 2 h) and freeze-thaw steps (-20 degrees C for 24 h, 5 degrees C for 24 h). When enumeration procedures did not include injury repair, the cran-cider process achieved a > or = 5-log reduction in numbers of E. coli O157:H7, Salmonella serovars, and Listeria monocytogenes. However, an injury-repair step was included in the pathogen enumeration procedure in confirmatory trials, and the resulting E. coli O157:H7 reductions of 3.5 to 4.2 log did not meet the FDA requirement. Consumer evaluation of apple cider subjected to the cran-cider process was favorable with a mean (n = 197) score of 5.8 on a seven-point hedonic scale (where 6 equals "like moderately") and 89% of panelists giving the product a positive score of 5, 6, or 7. The cran-cider process provides a novel way to improve microbial safety of unpasteurized apple cider, but it does not meet FDA-mandated pathogen reductions for wholesalers. However, cider makers selling apple cider only at retail could use the process to improve the safety of their product, provided containers were labeled with the FDA-mandated consumer warning.     

Reduction in levels of Escherichia coli O157:H7 in apple cider by pulsed electric fields.

Many studies have demonstrated that high voltage pulsed electric field (PEF) treatment has lethal effects on microorganisms including Escherichia coli O157:H7; however, the survival of this pathogen through the PEF treatment is not fully understood. Fresh apple cider samples inoculated with E. coli O157:H7 strain EC920026 were treated with 10, 20, and 30 instant charge reversal pulses at electric field strengths of 60, 70, and 80 kV/cm, at 20, 30, and 42 degrees C. To accurately evaluate the lethality of apple cider processing steps, counts were determined on tryptic soy agar (TSA) and sorbitol MacConkey agar (SMA) to estimate the number of injured and uninjured E. coli O157:H7 cells after PEF treatment. Cell death increased significantly with increased temperatures and electric field strengths. A maximum of 5.35-log10 CFU/ml (P < 0.05) reduction in cell population was achieved in samples treated with 30 pulses and 80 kV/cm at 42 degrees C. Cell injury measured by the difference between TSA and SMA counts was found to be insignificant (P > 0.05). Under extreme conditions, a 5.91-log10 CFU/ml reduction in cell population was accomplished when treating samples with 10 pulses and 90 kV/cm at 42 degrees C. PEF treatment, when combined with the addition of cinnamon or nisin, triggered cell death, resulting in a reduction in E. coli O157:H7 count of 6 to 8 log10 CFU/ml. Overall, the combination of PEF and heat treatment was demonstrated to be an effective pasteurization technique by sufficiently reducing the number of viable E. coli O157:H7 cells in fresh apple cider to meet U.S. Federal Drug Administration recommendations.     

Simultaneous detection of Escherichia coli O157:H7, Salmonella, and Shigella in apple cider and produce by a multiplex PCR

With three pairs of primers, a multiplex PCR assay was established for the simultaneous detection of Escherichia coli 0157:H7, Salmonella, and Shigella. Under the optimized conditions, the assay yielded a 252-bp product from E. coli O157:H7, a 429-bp product from Salmonella Typhimurium, and a 620-bp product from Shigella flexneri, respectively. When the DNA extraction of multiple target organisms was included in the same reaction, two or three corresponding amplicons of different sizes were observed. In the specificity test, 10 E. coli O157:H7 strains and one E. coli O157:NM strain showed the expected 252-bp amplicon. Seven other E. coli strains yielded no signal. Additionally, the 429-bp amplicon was produced from 20 Salmonella strains covering 16 serotypes, whereas the 620-bp amplicon was generated from 11 Shigella strains covering 4 species. No nonspecific amplification was observed with DNA from 48 other bacterial strains. Following a 24-h enrichment, the developed assay could concurrently detect the three pathogens at initial inoculation levels of approximately 8 x 10(-1) CFU/g (or CFU/ml) in apple cider, cantaloupe, lettuce, tomato, and watermelon and 8 x 10(1) CFU/g in alfalfa sprouts. The whole procedure can be easily completed within 30 h. The multiplex PCR assay can potentially be a simple, rapid, and efficient tool for presumptive and simultaneous screening of apple cider and produce for contamination by E. coli O157:H7, Salmonella, and/or Shigella.     

Inactivation of Escherichia coli O157:H7 and Salmonella in Apple Cider and Orange Juice Treated with Combinations of Ozone, Dimethyl Dicarbonate, and Hydrogen Peroxide

ABSTRACT: Inactivation of Escherichia coli O157:H7 and Salmonella in apple cider and orange juice treated with ozone in combination with antimicrobials was evaluated. E. coli O157:H7 or Salmonella was suspended in cider and orange juice, and ozone was pumped into juices (4°C) containing dimethyl dicarbonate (DMDC; 250 or 500 ppm) or hydrogen peroxide (300 or 600 ppm) for up to 90 min (study 1) or 60 min followed by 24-h storage at 4°C (study 2). Study 1: No combination of treatments resulted in a 5-log colony-forming units (CFU) /mL reduction of either pathogen. Study 2: All combinations of antimicrobials plus ozone treatments, followed by refrigerated storage, caused greater than a 5-log CFU/mL reduction, except ozone/DMDC (250 ppm) treatment in orange juice. Ozone treatment in combination with DMDC or hydrogen peroxide followed by refrigerated storage may provide an alternative to thermal pasteurization to meet the 5-log reduction standard in cider and orange juice.     

Polyphenol oxidase activity as a potential intrinsic index of adequate thermal pasteurization of apple cider

In response to increasing concerns about microbial safety of apple cider, the U.S. Food and Drug Administration has mandated treatment of cider sufficient for a 5-log reduction of the target pathogen. Pasteurization has been suggested as the treatment most likely to achieve a 5-log reduction, with Escherichia coli O157:H7 as the target pathogen. Regulators and processors need a reliable method for verifying pasteurization, and apple cider polyphenol oxidase (PPO) activity was studied as a potential intrinsic index for thermal pasteurization. The effect of pasteurization conditions and apple cider properties on PPO activity and survival of three pathogens (E. coli O157:H7, Salmonella, and Listeria monocytogenes) was studied using a Box-Behnken response surface design. Factors considered in the design were pasteurization conditions, i.e., hold temperature (60, 68, and 76 degrees C), preheat time (10, 20, 30 s), and hold time (0, 15, 30 s), pH, and sugar content ((o)Brix) of apple cider. Response surface contour plots were constructed to illustrate the effect of these factors on PPO activity and pathogen survival. Reduction in PPO activity of at least 50% was equivalent to a 5-log reduction in E. coli O157:H7 or L. monocytogenes for cider at pH 3.7 and 12.5 (o)Brix. Further studies, however, are needed to verify the relationship between PPO activity and pathogen reduction in cider with various pH and (o)Brix values.     

Modeling the survival of Escherichia coli O157:H7 in apple cider using probability distribution functions for quantitative risk assessment

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 degrees C]; temperature abuse [6 to 10 degrees C]; room temperature [20 to 25 degrees 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) x 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.     

Isolation and characterization of Escherichia coli recovered from Maryland apple cider and the cider production environment

Contaminated apple cider has been implicated in several Escherichia coli O157:H7 outbreaks. In an attempt to investigate sources and modes of entry of E. coli into apple cider, samples of fresh apple, pomace, and cider and equipment and mill floor swabs were analyzed for standard plate counts (SPC), total coliforms (TC), fecal coliforms (FC), and E. coli. E. coli was isolated from 14 (33%) of 42 samples of bottled fresh cider, from food equipment in 6 (67%) of 9 mills, and from apples, pomace, or cider in 7 (78%) of 9 mills. Seventy-five E. coli isolates were further characterized for Shiga toxin-producing E. coli (STEC)-associated virulence factors, antimicrobial susceptibility, and pulsed-field gel electrophoresis (PFGE) type. No E. coli O157:H7 or other STEC was identified. Serotyping and PFGE revealed 64 distinct profiles, suggesting that recovered E. coli arose from multiple independent sources. However, on one occasion, E. coli isolated from the source apple sample was closely related to the E. coli identified in the finished cider sample. E. coli isolates were further tested for antimicrobial susceptibility to 17 antimicrobial agents of human and veterinary importance. Fourteen (19%) of the 75 isolates were resistant to at least one of the antimicrobial agents tested, and 9 (12%) were resistant to at least two of these agents. Of the resistant isolates recovered, 64% were resistant to tetracycline and 57% were resistant to streptomycin. Overall, the level of E. coli contamination in source apple samples did not differ significantly from those in samples of pomace, cider at the press, and cider entering the bottling tank; therefore, source apples cannot be dismissed as a potential contributor of E. coli to the cider-making process.     

Inactivation of Escherichia coli K-12 in Apple Juice Using Combination of High-Pressure Homogenization and Chitosan

ABSTRACT:  Apple juice and apple cider were inoculated with Escherichia coli K-12 and processed using a high-pressure homogenizer to study bacterial inactivation. Seven levels of pressure ranging from 50 to 350 MPa were used in the high-pressure homogenizer. Two types of chitosan (regular and water soluble) with 2 levels of concentration 0.01% and 0.1% were investigated for synergistic effect with high-pressure homogenization for the bacterial inactivation. E. coli K-12 inactivation was evaluated as a function of homogenizing pressure at different concentration of 2 types of chitosan in apple juice and cider. High-pressure homogenization (HPH) induced significant inactivation in the range of 100 to 200 MPa, while thermal inactivation was the primary factor for the bacterial inactivation above 250 MPa. Significant ( P < 0.05) 2-way interactions involving pressure and type of substrate or pressure and chitosan concentration were observed during the study. The homogenization pressure and the incremental quantity of chitosan (both types) acted synergistically with the pressure to give higher inactivation. Significantly ( P < 0.05) higher inactivation was observed in apple juice than apple cider at same homogenizing pressure. No effect of type of chitosan was observed on the bacterial inactivation.     

UV INACTIVATION OF E. COLI O157:H7 IN APPLE CIDER: QUALITY, SENSORY AND SHELF-LIFE ANALYSIS

Increasing concern about food safety following contamination of unpasteurized apple cider with Escherichia coli O157:H7 reinforces the need for using the best technologies in apple cider production. Pasteurization of apple cider with ultraviolet irradiation (UV) is a low‐cost alternative to heat pasteurization for small processing operations. UV treatment efficacy applied to raw unpasteurized apple cider was examined through evaluation of physical parameters, exposure time and treatment dosage. A UV light processing system was used to treat apple cider. The apple cider received a calculated average dosage of 8777 µW‐s/cm ² per pass through the system. UV light (at 254.7 nm) was effective in reducing bacteria‐inoculated apple cider by an average of 2.20 logs per pass. In multiple passes, the 5‐log reduction mandated by the Food and Drug Administration was achieved. Sensory analysis yielded no significant differences between the UV‐treated and control apple ciders. Experiments with UV‐treated apple cider indicated a significant extension of product shelf life through inhibition of yeast and mold growth. For low throughput apple cider processing operations, this technology is a viable cost‐effective alternative.     

Modified immunoliposome sandwich assay for the detection of Escherichia coli O157:H7 in apple cider

Detection of Escherichia coli O157:H7 in fruit juices such as apple cider is necessary for diagnosis of infection and epidemiological investigations. However, inhibitors in the apple cider, such as endogenous polyphenols and acids, often decrease the sensitivity of PCR assays and immunoassays, thus routinely requiring laborious cell separation steps to increase the sensitivity. In the current study, polyethylene glycol (PEG)-derivatized liposomes encapsulating sulforhodamine B were tagged with anti-E. coli O157:H7 antibodies and used in an immunoliposome sandwich assay for the detection of E. coli O157:H7 in apple cider. Even without prior separation, this assay can detect E. coli O157:H7 in apple cider samples inoculated with as few as 1 CFU/ml after an 8-h enrichment period. The lower limit of detection in pure cultures without enrichment was 7 x 10(3) CFU/ml (280 CFU/40-microl sample). PEGylated immunoliposomes are suitable as an analytical reagent for the detection of E. coli O157:H7 in fruit juices containing polyphenols.     

Analysis and modeling of the variability associated with UV inactivation of Escherichia coli in apple cider

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 Analyticato describe these distributions, such as one would find in a quantitative risk assessment, are included.     

Presence and Stability of Patulin in Pasteurized Apple Cider

Pasteurized apple cider produced in Georgia was surveyed for patulin. Levels from 244-3993 μg patulin/L cider were found. Eight high temperature-short time (HTST) treatments (60°, 70°. 80°, and 90°C for 10 set; 90°C for 20, 40, 80, and 160 set) and one batch treatment (90°C for 10 min) were used to determine the stability of patulin in pasteurized cider. The 60°, 80°, and 90°C HTST treatments and the batch pasteurization significantly reduced the patulin level, but did not completely destroy the toxin. Storage of the cider had no effect on the patulin level.     

Modeling of Escherichia coli inactivation by UV irradiation at different pH values in apple cider

This study examined the effects and interactions of UV light dose (1,800 to 20,331 microJ/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 microJ/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.