scholarly journals Elimination of Escherichia coli O157:H7 from Fermented Dry Sausages at an Organoleptically Acceptable Level of Microencapsulated Allyl Isothiocyanate

2006 ◽  
Vol 72 (5) ◽  
pp. 3096-3102 ◽  
Author(s):  
Pedro A. Chacon ◽  
Parthiban Muthukumarasamy ◽  
Richard A. Holley
Keyword(s):  
Escherichia Coli ◽  
Starter Culture ◽  
Allyl Isothiocyanate ◽  
Starter Cultures ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Initial Ph ◽  
Pork Fat ◽  
Dry Sausages ◽  
Total Bacteria

ABSTRACT Four sausage batters (17.59% beef, 60.67% pork, and 17.59% pork fat) were inoculated with two commercial starter culture organisms (>7 log10 CFU/g Pediococcus pentosaceus and 6 log10 CFU/g Staphylococcus carnosus) and a five-strain cocktail of nonpathogenic variants of Escherichia coli O157:H7 to yield 6 to 7 log10 CFU/g. Microencapsulated allyl isothiocyanate (AIT) was added to three batters at 500, 750, or 1,000 ppm to determine its antimicrobial effects. For sensory analysis, separate batches with starter cultures and 0, 500, or 750 ppm microencapsulated AIT were produced. Sausages were fermented at ≤26�C and 88% relative humidity (RH) for 72 h. Subsequently sausages were dried at 75% RH and 13�C for at least 25 days. The water activity (aw), pH, and levels of starter cultures, E. coli O157:H7, and total bacteria were monitored during fermentation and drying. All sausages showed changes in the initial pH from 5.57 to 4.89 and in aw from 0.96 to 0.89 by the end of fermentation and drying, respectively. Starter culture numbers were reduced during sausage maturation, but there was no effect of AIT on meat pH reduction. E. coli O157:H7 was reduced by 6.5 log10 CFU/g in sausages containing 750 and 1,000 ppm AIT after 21 and 16 days of processing, respectively. E. coli O157:H7 numbers were reduced by 4.75 log10 CFU/g after 28 days of processing in treatments with 500 ppm AIT, and the organism was not recovered from this treatment beyond 40 days. During sensory evaluation, sausages containing 500 ppm AIT were considered acceptable although slightly spicy by panelists.

Inhibition of Escherichia coli O157:H7 in Ripening Dry Fermented Sausage by Ground Yellow Mustard

2008 ◽  
Vol 71 (3) ◽  
pp. 486-493 ◽  
Author(s):  
GARY H. GRAUMANN ◽  
RICHARD A. HOLLEY
Keyword(s):  
Escherichia Coli ◽  
Starter Culture ◽  
Escherichia Coli O157 ◽  
Fermented Sausage ◽  
Yellow Mustard ◽  
E Coli ◽  
Dry Fermented Sausage ◽  
Hydrolysis Of ◽  
Antimicrobial Effectiveness ◽  
Dry Sausage

Compounds generated by the enzymatic hydrolysis of glucosinolates naturally present in mustard powder are potently bactericidal against Escherichia coli O157:H7. Because E. coli O157:H7 can survive the dry fermented sausage manufacturing process, 2, 4, and 6% (wt/wt) nondeheated (hot) mustard powder or 6% (wt/wt) deheated (cold) mustard powder were added to dry sausage batter inoculated with E. coli O157:H7 at about 7 log CFU/g to evaluate the antimicrobial effectiveness of the powders. Reductions in E. coli O157:H7 populations, changes in pH and water activity (aw), effects on starter culture (Pediococcus pentosaceus and Staphylococcus carnosus) populations, and effects of mustard powder on sausage texture (shear) were monitored during ripening. Nondeheated mustard powder at 2, 4, and 6% in dry sausage (0.90 aw) resulted in significant reductions in E. coli O157:H7 (P < 0.05) of 3.4, 4.4, and 6.9 log CFU/g, respectively, within 30 days of drying. During fermentation and drying, mustard powder did not affect P. pentosaceus and S. carnosus activity in any of the treatments. Extension of drying to 36 and 48 days reduced E. coli O157:H7 by >5 log CFU/g in the 4 and 2% mustard powder treatments, respectively. The 6% deheated mustard powder treatment provided the most rapid reductions of E. coli O157:H7 (yielding <0.20 log CFU/g after 24 days) by an unknown mechanism and was the least detrimental (P < 0.05) to sausage texture.

Predicting Survival of Escherichia coli O157:H7 in Dry Fermented Sausage Using Artificial Neural Networks

2008 ◽  
Vol 71 (1) ◽  
pp. 6-12 ◽  
Author(s):  
A. PALANICHAMY ◽  
D. S. JAYAS ◽  
R. A. HOLLEY
Keyword(s):  
Escherichia Coli ◽  
Neural Networks ◽  
Artificial Neural Networks ◽  
Statistical Model ◽  
Allyl Isothiocyanate ◽  
Escherichia Coli O157 ◽  
Fermented Sausage ◽  
E Coli ◽  
Dry Fermented Sausage ◽  
Artificial Neural

The Canadian Food Inspection Agency required the meat industry to ensure Escherichia coli O157:H7 does not survive (experiences ≥ 5 log CFU/g reduction) in dry fermented sausage (salami) during processing after a series of foodborne illness outbreaks resulting from this pathogenic bacterium occurred. The industry is in need of an effective technique like predictive modeling for estimating bacterial viability, because traditional microbiological enumeration is a time-consuming and laborious method. The accuracy and speed of artificial neural networks (ANNs) for this purpose is an attractive alternative (developed from predictive microbiology), especially for on-line processing in industry. Data from a study of interactive effects of different levels of pH, water activity, and the concentrations of allyl isothiocyanate at various times during sausage manufacture in reducing numbers of E. coli O157:H7 were collected. Data were used to develop predictive models using a general regression neural network (GRNN), a form of ANN, and a statistical linear polynomial regression technique. Both models were compared for their predictive error, using various statistical indices. GRNN predictions for training and test data sets had less serious errors when compared with the statistical model predictions. GRNN models were better and slightly better for training and test sets, respectively, than was the statistical model. Also, GRNN accurately predicted the level of allyl isothiocyanate required, ensuring a 5-log reduction, when an appropriate production set was created by interpolation. Because they are simple to generate, fast, and accurate, ANN models may be of value for industrial use in dry fermented sausage manufacture to reduce the hazard associated with E. coli O157:H7 in fresh beef and permit production of consistently safe products from this raw material.

Survival of Escherichia coli O157:H7 in Full- and Reduced-Fat Pepperoni after Manufacture of Sticks, Storage of Slices at 4°C or 21°C under Air and Vacuum, and Baking of Slices on Frozen Pizza at 135, 191 and 246°C

1998 ◽  
Vol 61 (4) ◽  
pp. 383-389 ◽  
Author(s):  
NANCY G. FAITH ◽  
RACHEL K. WIERZBA ◽  
ANNE M. IHNOT ◽  
ANN M. ROERING ◽  
TIMOTHY D. LORANG ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Relative Humidity ◽  
Starter Culture ◽  
Escherichia Coli O157 ◽  
Protein Ratio ◽  
Direct Plating ◽  
E Coli ◽  
Reduced Fat ◽  
Log10 Unit ◽  
D Values

Pepperoni batter was prepared with fat contents of about 15, 20, and 32% (wt/wt) and inoculated with a pediococcal starter culture and ≥2.0 × 107 CFU/g of a five-strain inoculum of Escherichia coli O157:H7. The batter was fermented at 96°F (ca. 36°C) and 85% relative humidity (RH) to pH ≤ 4.8 and then dried at 55°F (ca. 13°C) and 65% RH to a moisture/protein ratio of ≤1.6:1. For storage, slices were packaged under air or vacuum and stored at 39°F (ca. 4°C) and 70°F (ca. 21°C). For baking, frozen slices were placed on retail frozen cheese pizzas that were subsequently baked at 275°F (ca. 135°C), 375°F (ca. 191°C), or 475°F (ca. 246°C) for 0 to 20 min. Appreciable differences related to fat levels were observed after drying; pathogen numbers decreased by 1.04, 1.31 and 1.62 log10 units in sticks prepared from batter at initial fat levels of 15, 20, and 32%, respectively. During storage, the temperature rather than the atmosphere had the greater effect on pathogen numbers, with similar viability observed among the three fat levels tested. At 70°F (ca. 21°C), compared to original levels, pathogen numbers decreased by ≥5.56 and ≥4.53 log10 units within 14 days in slices stored under air and vacuum, respectively, whereas at 39°F (ca. 4°C) numbers decreased by ≤2.43 log10 CFU/g after 60 days of storage under either atmosphere. Baking, as expected, resulted in greater reductions in pathogen numbers as the temperature and/or time of baking increased. However, it was still possible to recover the pathogen by enrichment after baking frozen slices on frozen pizza at 475°F (ca. 246°C) for 10 min or at 375°F (ca. 191°C) for 15 min. The calculated D values for all three temperatures tested increased as the fat content of the batter increased from 15 to 20 to 32%. The present study confirmed that fermentation and drying were sufficient to reduce levels of E. coli O157:H7 in pepperoni sticks by <2.0 log10 CFU/g. Storage of slices for at least 14 days at ambient temperature under air resulted in a >5.5-log10-unit total reduction of the pathogen. Baking slices on frozen pizza for at least 15 min at 475°F (ca. 246°C) or 20 min at 375°F (ca. 191°C) was necessary to reduce pathogen numbers to below detection by both direct plating and enrichment.

Inactivation of Escherichia coli O157:H7 and Salmonella and Native Microbiota on Fresh Strawberries by Antimicrobial Washing and Coating

2018 ◽  
Vol 81 (8) ◽  
pp. 1227-1235 ◽  
Author(s):  
MINGMING GUO ◽  
TONY Z. JIN ◽  
JOSHUA B. GURTLER ◽  
XUETONG FAN ◽  
MADHAV P. YADAV
Keyword(s):  
Escherichia Coli ◽  
Foodborne Pathogens ◽  
Allyl Isothiocyanate ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Native Microflora ◽  
Pathogen Populations ◽  
Antimicrobial Treatments ◽  
Antimicrobial Effectiveness

ABSTRACT Antimicrobial washing (AW), antimicrobial coating (AC), and a combination of washing followed by coating (AW+AC) were evaluated for their ability to inactivate artificially inoculated foodborne pathogens and native microbiota on strawberries stored at 4°C. Strawberries were inoculated with a six-strain composite of Escherichia coli O157:H7 and Salmonella; treated by AW, AC, or AW+AC; and stored at 4°C for 3 weeks. The washing solution contained 90 ppm of peracetic acid, and the coating solution consisted of chitosan (1%, w/v), allyl isothiocyanate (1%, v/v), and corn-bio fiber gum (5%, w/v). The effectiveness of the antimicrobial treatments against E. coli O157:H7 and Salmonella pathogens and native microflora on strawberries and their impact on fruit quality (appearance, weight loss, color, and firmness) were determined. By the end of storage, pathogen populations on strawberries were 2.5 (AW+AC), 2.9 (AC), 3.8 (AW), and 4.2 log CFU for the positive (untreated) control. AW+AC treatments also inactivated the greatest population of native microflora, followed by the AC treatment alone. AW+AC treatments showed additional antimicrobial effectiveness against these two pathogens and native microflora. Both AW+AC and AC treatments preserved the color, texture, and appearance of strawberries throughout storage. The coating treatments (AW+AC and AC alone) further reduced the loss of moisture throughout storage. The AW treatment was the least effective in reducing populations of pathogens and native microflora and in maintaining the quality of strawberries throughout storage. This study demonstrates a method to improve the microbiological safety, shelf life, and quality of strawberries.

Persistence of Escherichia coli O157:H7 in Dairy Fermentation Systems

1998 ◽  
Vol 61 (12) ◽  
pp. 1602-1608 ◽  
Author(s):  
SEAN S. DINEEN ◽  
KAZUE TAKEUCHI ◽  
JANE E. SOUDAH ◽  
KATHRYN J. BOOR
Keyword(s):  
Escherichia Coli ◽  
Lactococcus Lactis ◽  
Dairy Products ◽  
Starter Cultures ◽  
Escherichia Coli O157 ◽  
Potential Health ◽  
E Coli ◽  
Lactococcus Lactis Subsp ◽  
Fermented Dairy Products ◽  
Fermented Dairy

We examined (i) the persistence of Escherichia coli O157:H7 as a postpasteurization contaminant in fermented dairy products; (ii) the ability of E. coli O157:H7 strains with and without the general stress regulatory protein, RpoS, to compete with commercial starter cultures in fermentation systems; and (iii) the survival of E. coli O157:H7 in the yogurt production process. In commercial products inoculated with 103 CFU/ml, E. coli O157:H7 was recovered for up to 12 days in yogurt (pH 4.0), 28 days in sour cream (pH 4.3), and at levels >102 CFU/ml at 35 days in buttermilk (pH 4.1). For the starter culture competition trials, the relative inhibition of E. coli O157:H7 in the experimental fermentation systems was, in decreasing order, thermophilic culture mixture, Lactobacillus delbrueckii subsp. bulgaricus R110 alone, Lactococcus lactis subsp. lactis D280 alone, Lactococcus lactis subsp. cremoris D62 alone, and Streptococcus thermophilus C90 alone showing the least inhibition. Recovery of the rpoS mutant was lower than recovery of its wild-type parent by 72 h or earlier in the presence of individual starter cultures. No E. coli O157:H7 were recovered after the curd formation step in yogurt manufactured with milk inoculated with 105 CFU/ml. Our results show that (i) postprocessing entry of E. coli O157:H7 into fermented dairy products represents a potential health hazard; (ii) commercial starter cultures differ in their ability to reduce E. coli O157:H7 CFU numbers in fermentation systems; and (iii) the RpoS protein appears to most effectively contribute to bacterial survival in the presence of conditions that are moderately lethal to the cell.

Influence of NaCl and NaNO3 on Sinigrin Hydrolysis by Foodborne Bacteria

2011 ◽  
Vol 74 (12) ◽  
pp. 2162-2168 ◽  
Author(s):  
S. HERZALLAH ◽  
M. LARA LLEDÓ ◽  
R. HOLLEY
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Fluorescens ◽  
Starter Culture ◽  
Allyl Isothiocyanate ◽  
Escherichia Coli O157 ◽  
Bacterial Strains ◽  
Natural Antimicrobial ◽  
Staphylococcus Carnosus ◽  
Factors Influencing ◽  
Endogenous Plant

The glucosinolate sinigrin (SNG) is converted by endogenous plant myrosinase or by bacterial myrosinase-like activity to form the potent antimicrobial allyl isothiocyanate. In order to use SNG as a natural antimicrobial precursor in food, it became important to better understand the ability of bacteria to synthesize the enzyme(s) and understand factors influencing this synthesis at a constant SNG concentration. Eight spoilage, pathogenic, or starter culture bacteria were grown separately in medium containing individual or combined salts with SNG. SNG degradation by the bacteria and the formation of its major degradation product, allyl isothiocyanate, were followed for 12 days at 30 or 35°C. The bacterial strains varied in their ability to metabolize SNG, and this was enhanced by NaCl and/or NaNO3. SNG hydrolysis took place after 4 days, and the greatest amount occurred by day 12. At 12 days, Escherichia coli O157:H7 showed the greatest capacity to hydrolyze SNG (45.3% degradation), followed by Staphylococcus carnosus (44.57%), while Pseudomonas fluorescens was not active against SNG. The ability of tested strains to metabolize SNG, in decreasing order, was as follows: Escherichia coli O157:H7 > Staphylococcus carnosus > Staphylococcus aureus > Pediococcus pentosaceus > Salmonella Typhimurium > Listeria monocytogenes > Enterococcus faecalis > Pseudomonas fluorescens.

scholarly journals Survival of Shiga Toxin-Producing Escherichia coli (STEC) Serogroups During Production and Storage of Yogurt

2021 ◽  
Vol 72 (1) ◽  
pp. 2689
Author(s):  
G CELIK ◽  
A DIKICI ◽  
A KOLUMAN
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Starter Culture ◽  
Escherichia Coli O157 ◽  
Potential Health ◽  
Potential Health Risk ◽  
E Coli ◽  
Lactic Acid Content ◽  
And Storage ◽  
Lactobacillus Spp

In this study, the survival of Escherichia coli O157:H7 and non-O157 STEC serogroups of O26, O111, O103, and O145 were investigated during production and storage of yogurt. For this purpose, pathogens were individually inoculated into milk after pasteurization along with the starter culture (approximately 7.00±1.00 log10 cfu/g). After incubation at 44oC (about 180 min), yogurt samples were capped and stored at 4oC for 20 days. Pathogens were enumerated at 0, 5, 10, 15, and 20th days of storage. Lactic acid content (%) and pH of the samples were also screened. Moreover, mesophilic Lactococcus spp. and mesophilic Lactobacillus spp. were enumerated during production of yogurt.After incubation, the number of E. coli O157, O26, O103, O145, O111were 6.76±0.45, 6.64±0.53, 7.12±0.43, 6.00±1.39, 5.89±1.37 log10 cfu/g, respectively. A significant decrease was determined in all groups during the storage of yogurt samples at 4oC (p<0.05). It was detected on the 20th day of storage that the number of E. coli O157:H7 and non-O157 STEC serogroups of O103 and O145 were under the detection limit. However, STEC O26 and O111 were viable around 1.51±0.98 and 1.18±0.62 log10 cfu/g respectively. Results of the study showed that Escherichia coli O157:H7 and non-O157 STEC serogroups might pose a potential health risk during production and storage of yogurt.

Fate of Enterohemorrhagic Escherichia coli O157: H7 in Commercial Mayonnaise

1994 ◽  
Vol 57 (9) ◽  
pp. 780-783 ◽  
Author(s):  
TONG ZHAO ◽  
MICHAEL P. DOYLE
Keyword(s):  
Escherichia Coli ◽  
Enterohemorrhagic Escherichia Coli ◽  
Health Concern ◽  
Plate Count ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Initial Ph ◽  
Contaminated Food ◽  
Aerobic Plate Count ◽  
Mold And Yeast

The fate of enterohemorrhagic Escherichia coli O157:H7 was determined in three different lots of commercial mayonnaise, including four different samples from a lot implicated in an outbreak of E. coli O157:H7 infection. The initial pH of the products ranged from 3.6 to 3.9. Products were inoculated with 6.5 × 103 E. coli O157:H7/g and incubated at 5 or 20°C. Escherichia coli O157:H7 did not grow at either temperature but survived for 34 to 55 days at 5°C and for 8 to 21 days at 20°C, depending on the lot. Survival was greatest in real mayonnaise purchased at retail among six mayonnaise samples which included a reduced calorie mayonnaise. Escherichia coli O157:H7 populations decreased between 2- and 100-fold by 3 weeks at 5°C, and between 10- and 1,000-fold by 7 days at 20°C. There was little or no change in pH (&lt;0.1 unit), aerobic plate count, mold and yeast count or Lactobacillus count (&lt; 1 log10 CFU/g) for the duration of the study. Commercial mayonnaise manufactured under good manufacturing practices is not a public health concern. Abusive handling of mayonnaise resulting in cross-contamination with E. coli O157:H7-contaminated food or contamination by an infected foodhandler is the principal basis for concern.

Validation of Pepperoni Processes for Control of Escherichia coli O157:H7‡

1996 ◽  
Vol 59 (12) ◽  
pp. 1260-1266 ◽  
Author(s):  
JAY C. HINKENS ◽  
NANCY G. FAITH ◽  
TIMOTHY D. LORANG ◽  
PHILLIP BAILEY ◽  
DENNIS BUEGE ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Relative Humidity ◽  
Thermal Processing ◽  
Starter Culture ◽  
Escherichia Coli O157 ◽  
Protein Ratio ◽  
E Coli ◽  
Modified Method ◽  
Low Levels ◽  
Unit Reduction

The outbreak of Escherichia coli O157:H7 linked with dry-cured salami in late 1994 prompted regulatory action that required manufacturers of fermented products to demonstrate a 5-log unit reduction in counts of this pathogen during processing. Therefore, pepperoni batter (75% pork:25% beef with a fat content of ca. 32%) was inoculated with a pediococcal starter culture and a five-strain mixture of E. coli O157:H7 (≥2 × 107 CFU/g) and stuffed into 55-mm diameter fibrous casings 47 cm in length. The viability of the pathogen was monitored before stuffing, after fermentation, after thermal processing, and/or after drying. Chubs were fermented at 96°F (36°C) and 85% relative humidity (RH) to pH ≤ 5.0 and then dried at 55°F (13°C) and 65% RH to a moisture/protein ratio of ≤1.6:1 (modified method 6 process). Counts of the pathogen decreased about 1.2 log units after fermentation and drying. In subsequent experiments, heating chubs after fermentation to internal temperatures of 145°F (63°C) instantaneous or 128°F (53°C) for 60 min resulted in a ≥5-log unit decrease in numbers of strain O157:H7 without visibly affecting the texture or appearance of the product. These data revealed that a traditional nonthermal, process for pepperoni was only sufficient to eliminate relatively low levels (ca. 2 log CFU/g) of E. coli O157:H7, whereas heating to internal temperatures of 145°F (63°C) instantaneous or 128°F (53°C) for 60 min delivered a 5 to 6 log unit reduction in counts of the pathogen in pepperoni.

Viability of Escherichia coli O157:H7 in Salami Following Conditioning of Batter, Fermentation and Drying of Sticks, and Storage of Slices

1998 ◽  
Vol 61 (4) ◽  
pp. 377-382 ◽  
Author(s):  
NANCY G. FAITH ◽  
NELLY PARNIERE ◽  
TRINA LARSON ◽  
TIMOTHY D. LORANG ◽  
CHARLES W. KASPAR ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Storage Temperature ◽  
Starter Culture ◽  
Escherichia Coli O157 ◽  
Protein Ratio ◽  
E Coli ◽  
Log10 Unit ◽  
Storage Atmosphere ◽  
Unit Reduction ◽  
And Storage

The fate of Escherichia coli O157:H7 was monitored in salami during conditioning of batter, fermentation and drying of sticks, and storage of slices. The raw batter (75% pork:25% beef, wt/wt, fat content about 20%) was inoculated with a pediococcal starter culture (about 108 CFU/g) and a five-strain cocktail of E. coli O157:H7 (≥2 × 107 CFU/g) and stuffed into 104-mm diameter fibrous casings. After being refrigerated at 4°C or being tempered at 13°C, frozen at −20°C, and thawed at 4°C, or being frozen at −20°C, and thawed at 4°C, the inoculated batter was fermented at 24°C and 90% relative humidity (RH) to pH ≤4.8, dried at 13°C and 65% RH to a moisture/protein ratio of ≤1.9:1, and then stored at 4 or 21°C under air or vacuum. For salami sticks sampled immediately after drying, appreciable differences were evident among the various batter-conditioning treatments; pathogen numbers were reduced from original levels by 2.1, 1.6, or 1.1 log10 units when batter was tempered, frozen, and thawed, frozen and thawed, or refrigerated, respectively. Similarly, regardless of storage temperature or atmosphere, within 7 days salami slices cut from sticks prepared from batter that was tempered, frozen, and thawed (2.7- to 4.9-log10-unit reduction) or frozen and thawed (2.3- to 4.8-log10-unit reduction) displayed a greater impact on pathogen numbers than slices cut from sticks prepared from batter that was refrigerated (1.6- to 3.1-log10-unit reduction). The effects of batter conditioning notwithstanding, a greater reduction in levels of E. coli O157:H7 was observed when slices were stored at 21°C compared to otherwise similar slices stored at 4°C. After storage for 60 days the pathogen was only detected by enrichment in slices stored at 21°C, whereas pathogen levels ranged from 1.4 to 4.5 log10 CFU/g in slices stored at 4°C. Differences related to storage atmosphere were first observed after slices were stored for 21 days. Such differences were more readily demonstrable after 60 and 90 days, with pathogen numbers for treatments that were statistically different ranging from 0.6- to 1.5-log10 units higher on slices stored under vacuum than in air. These data emphasize the need to implement multiple barriers to appreciably reduce numbers of E. coli O157:H7 in salami.

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