Effects of Dry Chilling on the Microflora on Beef Carcasses at a Canadian Beef Packing Plant

2016 ◽  
Vol 79 (4) ◽  
pp. 538-543 ◽  
Author(s):  
Y. LIU ◽  
M. K. YOUSSEF ◽  
X. YANG
Keyword(s):  
Escherichia Coli ◽  
Relative Humidity ◽  
Air Temperature ◽  
Ambient Air ◽  
Indicator Organisms ◽  
Air Velocity ◽  
E Coli ◽  
Beef Carcasses ◽  
Significant Difference

ABSTRACT The aim of this study was to determine the course of effects on the microflora on beef carcasses of a commercial dry chilling process in which carcasses were dry chilled for 3 days. Groups of 25 carcasses selected at random were sampled when the chilling process commenced and after the carcasses were chilled for 1, 2, 4, 6, 8, 24, and 67 h for determination of the numbers of aerobes, coliforms, and Escherichia coli. The temperatures of the surfaces and the thickest part of the hip (deep leg) of carcasses, as well as the ambient air conditions, including air temperature, velocity, and relative humidity (RH), were monitored throughout the chilling process. The chiller was operated at 0°C with an off-coil RH of 88%. The air velocity was 1.65 m/s when the chiller was loaded. The initial RH levels of the air in the vicinity of carcasses varied with the locations of carcasses in the chiller and decreased rapidly during the first hour of chilling. The average times for shoulder surfaces, rump surfaces, and the deep leg of carcasses to reach 7°C were 13.6 ± 3.1, 16.0 ± 2.4 and 32.4 ± 3.2 h, respectively. The numbers of aerobes, coliforms, and E. coli on carcasses before chilling were 5.33 ± 0.42, 1.95 ± 0.77, 1.42 ± 0.78 log CFU/4,000 cm2, respectively. The number of aerobes on carcasses was reduced by 1 log unit each in the first hour of chilling and in the subsequent 23 h of chilling. There was no significant difference (P > 0.05) between the numbers of aerobes recovered from carcasses after 24 and 67 h of chilling. The total numbers (log CFU/100,000 cm2) on carcasses before chilling and after the first hour of chilling were 3.86 and 2.24 for coliforms and 3.30 and 2.04 for E. coli. The subsequent 23 h of chilling reduced the numbers of both groups of organisms by a further log unit. No coliforms or E. coli were recovered after 67 h of chilling. The findings show that the chilling regime investigated in this study resulted in significant reductions of all three groups of indicator organisms.

Recovery of Escherichia coli Biotype I and Enterococcus spp. during Refrigerated Storage of Beef Carcasses Inoculated with a Fecal Slurry

1999 ◽  
Vol 62 (8) ◽  
pp. 944-947 ◽  
Author(s):  
M. CALICIOGLU ◽  
D. R. BUEGE ◽  
S. C. INGHAM ◽  
J. B. LUCHANSKY
Keyword(s):  
Escherichia Coli ◽  
Storage Period ◽  
Most Probable Number ◽  
Probable Number ◽  
E Coli ◽  
Viable Cells ◽  
Beef Carcasses ◽  
Significant Difference ◽  
Enterococcus Spp ◽  
Appreciable Reduction

Three beef front quarters/carcasses were inoculated with a slurry of cattle manure. During storage at 4°C, two sponge samples from each of three sites (i.e., 100 cm2 from each of two fat surfaces and 100 cm2 from a lean surface) were taken from each of the three carcasses on days 0, 1, 3, 7, and 10 after inoculation. The initial numbers of Escherichia coli averaged 2.0 log10 CFU/cm2 (1.21 to 2.47 log10 CFU/cm2) using the Petrifilm method and 2.09 log10 most probable number (MPN)/cm2 (0.88 to 2.96 log10 MPN/cm2) using the MPN method. The initial numbers of enterococci averaged 3.34 log10 CFU/cm2 (3.07 to 3.79 log10 CFU/cm2) using kanamycin esculin azide agar. In general, an appreciable reduction in the numbers of E. coli occurred during the first 24 h of storage; for the Petrifilm method an average reduction of 1.37 log10 CFU/cm2 (0.69 to 1.71 log10 CFU/cm2) was observed, and for the MPN method an average reduction of 1.52 log10 MPN/cm2 (0.47 to 2.08 log10 MPN/cm2) was observed. E. coli were not detected (<−0.12 log10 CFU/cm2) using Petrifilm on day 7 of the storage period on two (initial counts of 1.21 and 2.29 log10 CFU/cm2) of the three carcasses. However, viable E. coli cells were recovered from these two carcasses after a 24-h enrichment at 37°C in EC broth. Viable E. coli cells were detected at levels of −0.10 log10 CFU/cm2 on the third carcass (initial count of 2.47 log10 CFU/cm2) after 7 days at 4°C. No significant difference in recovery of viable cells was observed between the MPN and Petrifilm methods on days 0, 1, and 3 (P > 0.05). However, viable E. coli cells were recovered from all three carcasses by the MPN method on day 7 at an average of −0.29 log10 MPN/cm2 (−0.6 to −0.1 log10 MPN/cm2). On day 10, viable cells were recovered by the MPN method from two of the three carcasses at −0.63 and −0.48 log10 MPN/cm2 but were not recovered from the remaining carcass (<−0.8 log10 MPN/cm2). Similar to E. coli, the greatest reduction (average of 1.26 log10 CFU/cm2, range = 1.06 to 1.45 log10 CFU/cm2) in the numbers of enterococci occurred during the first 24 h of storage. Because of higher initial numbers and a slightly slower rate of decrease, the numbers of Enterococcus spp. were significantly higher (P < 0.017) than the numbers of E. coli Biotype I after 3, 7, and 10 days of storage. These results suggest that enterococci may be useful as an indicator of fecal contamination of beef carcasses.

A New Technique for Escherichia coli Testing of Beef and Pork Carcasses†

2002 ◽  
Vol 65 (1) ◽  
pp. 192-195 ◽  
Author(s):  
J. J. ERDMANN ◽  
J. S. DICKSON ◽  
M. A. GRANT
Keyword(s):  
Escherichia Coli ◽  
Membrane Filtration ◽  
Total Coliform ◽  
Mean Values ◽  
E Coli ◽  
Coliform Count ◽  
Beef Carcasses ◽  
Significant Difference ◽  
The Mean ◽  
A New Technique

A novel technique has been developed to monitor Escherichia coli contamination on carcasses using membrane filtration and m-ColiBlue24 (mCB). mCB is a membrane filtration medium that simultaneously detects total coliforms and E. coli (EC) in a period of 24 ± 4 h. A study was conducted, using a sponge method to obtain samples from pork carcasses and the excision technique to remove samples from beef carcasses, that compared mCB to standard methods. On pork carcasses (n = 77), the mean values for mCB and violet red bile agar were 7.4 CFU/15 cm2 and 6.1 CFU/15 cm2, respectively. The paired t test (P > 0.05) indicated no significant difference between the two methods (t = 0.5; P = 0.6). Samples from beef carcasses (n = 57) were used to compare mCB to both coliform count and EC Petrifilm. Of these samples, 27 were artificially inoculated with cattle manure. The mean total coliform count was 4.2 log CFU/cm2 and 4.0 log CFU/cm2 on mCB and coliform count Petrifilm, respectively. The mean EC count on mCB was 4.0 log CFU/cm2 and 3.5 log CFU/cm2 on EC Petrifilm. When comparing mCB to both coliform count (t = 2.4; P = 0.02) and EC (t = 3.5; P < 0.01) Petrifilm, paired t tests (P ≤ 0.05) indicated significant differences.

Role of Bacterial Association and Penetration on Destruction of Escherichia coli O157:H7 in Beef Tissue by High pH

2000 ◽  
Vol 63 (1) ◽  
pp. 3-11 ◽  
Author(s):  
JON-MIKEL WOODY ◽  
ROSEMARY A. WALSH ◽  
STEPHANIE DOORES ◽  
WILLIAM R. HENNING ◽  
RICHARD A. WILSON ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Type I Collagen ◽  
Type I ◽  
Escherichia Coli O157 ◽  
Scanning Electron Micrographs ◽  
High Ph ◽  
E Coli ◽  
Beef Carcasses ◽  
Significant Difference ◽  
Scanning Electron

This study was undertaken to determine if association with collagen enables Escherichia coli O157:H7 to resist high-pH treatments and to determine the effects of high pH on the survival of E. coli O157:H7 within different layers of beef tissue. E. coli O157:H7 was inoculated onto purified bovine type I collagen on 12-mm2 circular glass coverslips, plain 12-mm2 circular glass coverslips (control), and 12-mm2 irradiated (cobalt-60) lean beef tissue. The rates of destruction of E. coli O157: H7 inoculated on coverslips in pH 10.5 NaHCO3-NaOH buffer at 35°C were determined at various sampling times. E. coli O157:H7 cells associated with collagen and treated in the same manner were also examined using scanning electron microscopy to determine if association with collagen enabled the organism to resist high-pH treatments. The inoculated tissue was treated in pH 13.0 NaHCO3-NaOH buffer at 25°C, and penetrating cells of E. coli O157:H7 were recovered using a cryostat technique. There was no significant difference (P < 0.05) between the rates of destruction of collagen-associated E. coli O157:H7 and non–collagen-associated E. coli O157:H7 following exposure to high-pH treatments. Scanning electron micrographs showed that collagen-associated E. coli O157:H7 cells appeared physically damaged by exposure to high-pH treatments, and association of E. coli O157:H7 to collagen did not increase the resistance of the organism to destruction by high-pH rinses. No significant differences were seen between 20 ml of NaHCO3-NaOH buffer at pH 13.0 (treatment) and 20 ml of distilled water at pH 7.0 (control) when E. coli O157:H7 cells were recovered in beef tissue at depths of up to 2,000 μm (P < 0.05). The ability of E. coli O157:H7 to penetrate beef tissue may be an important factor in reducing the effectiveness of high-pH treatments in killing this organism on beef tissue. This finding should be considered in the future when designing treatments to decontaminate beef carcasses.

scholarly journals Effect of Weather on the Die-Off of Escherichia coli and Attenuated Salmonella enterica Serovar Typhimurium on Preharvest Leafy Greens following Irrigation with Contaminated Water

2020 ◽  
Vol 86 (17) ◽  
Author(s):  
Alexandra M. Belias ◽  
Adrian Sbodio ◽  
Pilar Truchado ◽  
Daniel Weller ◽  
Janneth Pinzon ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Relative Humidity ◽  
Scientific Evidence ◽  
Weather Conditions ◽  
Rapid Decline ◽  
Indicator Organisms ◽  
Content Type ◽  
E Coli ◽  
Log Linear ◽  
The Impact

ABSTRACT The Food Safety Modernization Act (FSMA) includes a time-to-harvest interval following the application of noncompliant water to preharvest produce to allow for microbial die-off. However, additional scientific evidence is needed to support this rule. This study aimed to determine the impact of weather on the die-off rate of Escherichia coli and Salmonella on spinach and lettuce under field conditions. Standardized, replicated field trials were conducted in California, New York, and Spain over 2 years. Baby spinach and lettuce were grown and inoculated with an ∼104-CFU/ml cocktail of E. coli and attenuated Salmonella. Leaf samples were collected at 7 time points (0 to 96 h) following inoculation; E. coli and Salmonella were enumerated. The associations of die-off with study design factors (location, produce type, and bacteria) and weather were assessed using log-linear and biphasic segmented log-linear regression. A segmented log-linear model best fit die-off on inoculated leaves in most cases, with a greater variation in the segment 1 die-off rate across trials (−0.46 [95% confidence interval {95% CI}, −0.52, −0.41] to −6.99 [95% CI, −7.38, −6.59] log10 die-off/day) than in the segment 2 die-off rate (0.28 [95% CI, −0.20, 0.77] to −1.00 [95% CI, −1.16, −0.85] log10 die-off/day). A lower relative humidity was associated with a faster segment 1 die-off and an earlier breakpoint (the time when segment 1 die-off rate switches to the segment 2 rate). Relative humidity was also found to be associated with whether die-off would comply with FSMA’s specified die-off rate of −0.5 log10 die-off/day. IMPORTANCE The log-linear die-off rate proposed by FSMA is not always appropriate, as the die-off rates of foodborne bacterial pathogens and specified agricultural water quality indicator organisms appear to commonly follow a biphasic pattern with an initial rapid decline followed by a period of tailing. While we observed substantial variation in the net culturable population levels of Salmonella and E. coli at each time point, die-off rate and FSMA compliance (i.e., at least a 2 log10 die-off over 4 days) appear to be impacted by produce type, bacteria, and weather; die-off on lettuce tended to be faster than that on spinach, die-off of E. coli tended to be faster than that of attenuated Salmonella, and die-off tended to become faster as relative humidity decreased. Thus, the use of a single die-off rate for estimating time-to-harvest intervals across different weather conditions, produce types, and bacteria should be revised.

Attachment of Bacteria to Beef from Steam-Pasteurized Carcasses

2001 ◽  
Vol 64 (4) ◽  
pp. 493-497 ◽  
Author(s):  
K. WARRINER ◽  
K. EVELEIGH ◽  
J. GOODMAN ◽  
G. BETTS ◽  
M. GONZALES ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Bacterial Species ◽  
Bacterial Attachment ◽  
Pseudomonas Fragi ◽  
E Coli ◽  
Beef Carcasses ◽  
Significant Difference ◽  
Attachment Strength ◽  
Steam Pasteurization ◽  
Treatment Use

The extent to which a bacterial cocktail containing equal numbers of Pseudomonas fragi NCTC 10689, Listeria monocytogenes BL5/2, Salmonella Typhimurium LT2, and Escherichia coli JM 109 attached to loin surface cuts (7 by 5 cm) derived from steam-pasteurized beef carcasses has been evaluated. The extent of attachment was categorized as loosely attached (removed by rinsing), firmly attached (released by stomaching), and irreversibly bound. No significant difference (P > 0.10) in the attachment of bacteria to steam-pasteurized carcasses was found compared with control loin samples that had received no treatment. No significant difference (P > 0.05) was also found in the attachment strength between the different bacterial species tested. Most bacteria inoculated onto the loin cuts were reversibly bound, since they had been removed by rinsing and stomaching. The irreversible attachment of bacteria to loin cuts was found to vary significantly (P < 0.01) among the different carcass sets used but was independent of whether the carcass had undergone steam pasteurization treatment. Use of a bioluminescent strain of E. coli showed that cells bound preferentially to cut edges and convoluted areas on the loin surface and could not be removed by rinsing. The possible mechanisms of bacterial attachment and the suitability of steam pasteurization to remove contamination incurred during slaughter are discussed.

scholarly journals Distribution of Sulfonamide Resistance Genes in Escherichia coli and Salmonella Isolates from Swine and Chickens at Abattoirs in Ontario and Québec, Canada

2009 ◽  
Vol 75 (18) ◽  
pp. 5999-6001 ◽  
Author(s):  
Gosia K. Kozak ◽  
David L. Pearl ◽  
Julia Parkman ◽  
Richard J. Reid-Smith ◽  
Anne Deckert ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Resistance Genes ◽  
E Coli ◽  
Significant Difference ◽  
Sulfonamide Resistance ◽  
Sulfonamide Resistance Genes

ABSTRACT Sulfonamide-resistant Escherichia coli and Salmonella isolates from pigs and chickens in Ontario and Québec were screened for sul1, sul2, and sul3 by PCR. Each sul gene was distributed differently across populations, with a significant difference between distribution in commensal E. coli and Salmonella isolates and sul3 restricted mainly to porcine E. coli isolates.

Evaluation of the influence of ambient air temperature and air velocity on mortar cement durability using a forced convection solar dryer

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Younes Bahammou ◽  
Mounir Kouhila ◽  
Haytem Moussaoui ◽  
Hamza Lamsyehe ◽  
Zakaria Tagnamas ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Forced Convection ◽  
Air Temperature ◽  
Building Materials ◽  
Ambient Air ◽  
Physical Significance ◽  
Drying Process ◽  
Air Velocity ◽  
Content Type ◽  
Ambient Air Temperature

PurposeThis work aims to study the hydrothermal behavior of mortar cement toward certain environmental factors (ambient air temperature and air velocity) based on its drying kinetics data. The objective is to provide a better understanding and controlling the stability of mortar structures, which integrate the sorption phenomenon, drying process, air pressure and intrinsic characteristics. This leads to predict the comportment of mortar structures in relation with main environmental factors and minimize the risk of cracking mortar structures at an early age.Design/methodology/approachThermokinetic study was carried out in natural and forced convection solar drying at three temperatures 20, 30 and 40°C and three air velocities (1, 3 and 5 m.s-1). The empirical and semiempirical models tested successfully describe the drying kinetics of mortar. These models simulate the drying process of water absorbed by capillarity, which is the most common humidity transfer mechanism in building materials and contain parameters with physical significance, which integrate the effect of several environmental factors and intrinsic characteristics of mortar structures.FindingsThe models simulate the drying process of water absorbed by capillarity, which is the most common humidity transfer mechanism in building materials and contain parameters with physical significance, which integrate the effect of several environmental factors and intrinsic characteristics of mortar structures. The average activation energy obtained expressed the temperature effect on the mortar diffusivity. The drying constant and the diffusion coefficient can be used to predict the influence of these environmental factors on the drying behavior of various building materials and therefore on their durability.Originality/valueEvaluation of the effect of several environmental factors and intrinsic characteristics of mortar structures on their durability.

Changes in Aerobic Plate and Escherichia coli–Coliform Counts and in Populations of Inoculated Foodborne Pathogens on Inshell Walnuts during Storage

2016 ◽  
Vol 79 (7) ◽  
pp. 1143-1153 ◽  
Author(s):  
JOHN C. FRELKA ◽  
GORDON R. DAVIDSON ◽  
LINDA J. HARRIS
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Relative Humidity ◽  
Low Temperature ◽  
Foodborne Pathogens ◽  
Limit Of Detection ◽  
Sampling Time ◽  
E Coli ◽  
Plate Counts ◽  
Forced Air

ABSTRACT After harvest, inshell walnuts are dried using low-temperature forced air and are then stored in bins or silos for up to 1 year. To better understand the survival of bacteria on inshell walnuts, aerobic plate counts (APCs) and Escherichia coli–coliform counts (ECCs) were evaluated during commercial storage (10 to 12°C and 63 to 65% relative humidity) over 9 months. APCs decreased by 1.4 to 2.0 log CFU per nut during the first 5 months of storage, and ECCs decreased by 1.3 to 2.2 log CFU per nut in the first month of storage. Through the remaining 4 to 8 months of storage, APCs and ECCs remained unchanged (P > 0.05) or decreased by <0.15 log CFU per nut per month. Similar trends were observed on kernels extracted from the inshell walnuts. APCs and ECCs were consistently and often significantly higher on kernels extracted from visibly broken inshell walnuts than on kernels extracted from visibly intact inshell walnuts. Parameters measured in this study were used to determine the survival of five-strain cocktails of E. coli O157:H7, Listeria monocytogenes, and Salmonella inoculated onto freshly hulled inshell walnuts (~8 log CFU/g) after simulated commercial drying (10 to 12 h; 40°C) and simulated commercial storage (12 months at 10°C and 65% relative humidity). Populations declined by 2.86, 5.01, and 4.40 log CFU per nut for E. coli O157:H7, L. monocytogenes, and Salmonella, respectively, after drying and during the first 8 days of storage. Salmonella populations changed at a rate of −0.33 log CFU per nut per month between days 8 and 360, to final levels of 2.83 ± 0.79 log CFU per nut. E. coli and L. monocytogenes populations changed by −0.17 log CFU per nut per month and −0.26 log CFU per nut per month between days 8 and 360, respectively. For some samples, E. coli or L. monocytogenes populations were below the limit of detection by plating (0.60 log CFU per nut) by day 183 or 148, respectively; at least one of the six samples was positive at each subsequent sampling time by either plating or by enrichment.

Potential Public Health Significance of Non-Escherichia coli Coliforms in Food

1979 ◽  
Vol 42 (2) ◽  
pp. 161-163 ◽  
Author(s):  
ROBERT M. TWEDT ◽  
BRENDA K. BOUTIN
Keyword(s):  
Public Health ◽  
Escherichia Coli ◽  
Diarrheal Disease ◽  
Health Hazard ◽  
High Yield ◽  
Potential Health ◽  
E Coli ◽  
Potential Health Hazard ◽  
Health Significance

Several coliform species other than Escherichia coli are often associated with and possibly responsible for acute and chronic diarrheal disease. Recent evidence suggests that non-Escherichia coli coliforms may be capable of colonizing the human intestine and producing enterotoxin(s) in high-yield. Whether these organisms are newly capable of causing disease because of infestation with extrachromosomal factors mediating pathogenicity or simply because of inherent pathogenic capabilities that have gone unrecognized, they pose a potential health hazard. Food, medical, and public health microbiologists should be aware that the non-E. coli coliforms contaminating foods may be potential enteropathogens. This possibility may make determination of their pathogenic capabilities even more important than identification of their taxonomic characteristics.

Thermal Lethality of Salmonella in Chicken Leg Quarters Processed via an Air/Steam Impingement Oven

2004 ◽  
Vol 67 (3) ◽  
pp. 493-498 ◽  
Author(s):  
R. Y. MURPHY ◽  
K. H. DRISCOLL ◽  
L. K. DUNCAN ◽  
T. OSAILI ◽  
J. A. MARCY
Keyword(s):  
Relative Humidity ◽  
Surface Area ◽  
Air Temperature ◽  
Cooking Time ◽  
Air Velocity ◽  
Poultry Products ◽  
Product Surface ◽  
Cooking Times

Chicken leg quarters were injected with 0.1 ml of the cocktail culture per cm2 of the product surface area to contain about 7 log(CFU/g) of Salmonella. The inoculated leg quarters were processed in an air/steam impingement oven at an air temperature of 232°C, an air velocity of 1.4 m/s, and a relative humidity of 43%. The endpoint product temperatures were correlated with the cooking times. A model was developed for pathogen thermal lethality up to 7 log(CFU/g) reductions of Salmonella in correlation to the product mass (140 to 540 g) and cooking time (5 to 35 min). The results from this study are useful for validating thermal lethality of pathogens in poultry products that are cooked via impingement ovens.

Sign in / Sign up

Export Citation Format

Share Document