scholarly journals Calculation of the expected increases of coliform organisms,Escherichia coliandSalmonella typhimurium, in raw blended mutton tissue

1987 ◽  
Vol 99 (2) ◽  
pp. 323-331 ◽  
Author(s):  
M. G. Smith
Keyword(s):  
Escherichia Coli ◽  
Polyvinyl Chloride ◽  
Temperature Measurements ◽  
Tissue Samples ◽  
Codes Of Practice ◽  
Generation Times ◽  
Before And After ◽  
Plate Counts

SUMMARYSamples of blended mutton tissue in small polyvinyl chloride sachets were incubated in water baths for different times and at varying temperatures. The temperature of each bath was recorded accurately throughout each experiment. Using equations previously derived for the lag and generation times of coliform organisms in blended mutton tissue, the expected increases of these bacteria were calculated from the time/temperature recordings. These were compared with the data obtained from plate counts made on the tissue samples in the sachets before and after incubation. The studies were done with a strain ofEscherichia coli, one ofSalmonella lyphimuriumand the coliform organisms naturally present on sheep carcasses processed in a commercial abattoir. The calculated growth agreed closely with that measured. Therefore, if mutton, after overnight chilling, is warmed again to temperatures within the growth range of these bacteria, the possible increases in the numbers of cells present can be calculated directly from time and temperature measurements.The implications for the present codes of practice in abattoirs are discussed.

Effectiveness of a Laboratory-Scale Vertical Tower Static Chamber Steam Pasteurization Unit against Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria innocua on Prerigor Beef Tissue†

2004 ◽  
Vol 67 (8) ◽  
pp. 1630-1633 ◽  
Author(s):  
DEANNA RETZLAFF ◽  
RANDALL PHEBUS ◽  
ABBEY NUTSCH ◽  
JAMES RIEMANN ◽  
CURTIS KASTNER ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Salmonella Typhimurium ◽  
Cold Water ◽  
Laboratory Scale ◽  
Listeria Innocua ◽  
Steam Treatment ◽  
Escherichia Coli O157 ◽  
Tissue Samples ◽  
Before And After ◽  
Steam Pasteurization

A laboratory-scale vertical tower steam pasteurization unit was evaluated to determine the antimicrobial effectiveness of different exposure times (0, 3, 6, 12, and 15 s) and steam chamber temperatures (82.2, 87.8, 93.3, and 98.9°C) against pathogens (Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria innocua) inoculated onto prerigor beef tissue. Samples were collected and microbiologically analyzed immediately before and after steam treatment to quantify the effectiveness of each time-temperature combination. The 0-s exposure at all chamber temperatures (cold water spray only, no steam treatment) was the experimental control and provided ≤0.3 log CFU/cm2 reductions. Chamber temperatures of 82.2 and 87.8°C were ineffective (P > 0.05) at all exposure times. At 93.3°C, significant reductions (>1.0 log CFU/cm2) were observed at exposure times of ≥6 s, with 15 s providing approximately 1 log cycle greater reductions than 12 s of exposure. The 98.9°C treatment was consistently the most effective, with exposure times of ≥9 s resulting in >3.5 log CFU/cm2 reductions for all pathogens.

scholarly journals Comparison of Steam Pasteurization and Other Methods for Reduction of Pathogens on Surfaces of Freshly Slaughtered Beef

1997 ◽  
Vol 60 (5) ◽  
pp. 476-484 ◽  
Author(s):  
RANDALL K. PHEBUS ◽  
ABBEY L. NUTSCH ◽  
DAVID E. SCHAFER ◽  
R. CRAIG WILSON ◽  
M. JAMES RIEMANN ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Hot Water ◽  
Tissue Samples ◽  
Bacterial Populations ◽  
Water Steam ◽  
Before And After ◽  
Pathogen Populations ◽  
Steam Pasteurization

The effectiveness of a recently invented “steam pasteurization” (S) process in reducing pathogenic bacterial populations on surfaces of freshly slaughtered beef was determined and compared with that of other standard commercial methods including knife trimming (T), water washing (35°C; W), hot water/steam vacuum spot cleaning (V), and spraying with 2% vol/vol lactic acid (54°C, pH 2.25; L). These decontamination treatments were tested individually and in combinations. Cutaneus trunci muscles from freshly slaughtered steers were inoculated with feces containing Listeria monocytogenes Scott A, Escherichia coli OI57:H7, and Salmonella typhimurium over a predesignated meat surface area, resulting in initial populations of ca. 5 log CFU/cm2 of each pathogen. Tissue samples were excised from each portion before and after decontamination treatments, and mean population reductions were determined. Treatment combinations evaluated were the following (treatment designations within the abbreviations indicate the order of application): TW, TWS, WS, VW, VWS, TWLS, and VWLS. These combinations resulted in reductions ranging from 3.5 to 5.3 log CFU/cm2 in all three pathogen populations. The TW, TWS, WS, TWLS, and VWLS combinations were equally effective (P > 0.05), resulting in reductions ranging from 4.2 to 5.3 log CFU/cm2. When used individually, T, V, and S resulted in pathogen reductions ranging from 2.5 to 3.7 log CFU/cm2 Steam pasteurization consistently provided numerically greater pathogen reductions than T or V. Treatments T, V, and S were all more effective than W (which gave a reduction on the order of 1.0 log CFU/cm2). Steam pasteurization is an effective method for reducing pathogenic bacterial populations on surfaces of freshly slaughtered beef, with multiple decontamination procedures providing greatest overall reductions.

Chemical Dehairing of Bovine Skin To Reduce Pathogenic Bacteria and Bacteria of Fecal Origin†

1998 ◽  
Vol 61 (5) ◽  
pp. 623-625 ◽  
Author(s):  
A. CASTILLO ◽  
J. S. DICKSON ◽  
R. P. CLAYTON ◽  
L. M. LUCIA ◽  
G. R. ACUFF
Keyword(s):  
Escherichia Coli ◽  
Detection Limit ◽  
Pathogenic Bacteria ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Final Count ◽  
Before And After ◽  
Plate Counts ◽  
Bovine Hide ◽  
Bovine Feces

A Chemical dehairing process was applied to artificially contaminated bovine hide to evaluate the effect on populations of Escherichia coli O157:H7 and Salmonella Typhimurium, as well as other strains of E. coli, total coliforms, and aerobic plate counts (APC). Pieces of hide (4 cm2) were contaminated with bovine feces inoculated with both rifampicin-resistant E. coli O157:H7 and S. Typhimurium to yield a final count of each pathogen of ca. 5.0 log10 CFU/cm2, or with noninoculated feces which produced an approximate final APC of 6.0 log10 CFU/cm2 and a coliform and E. coli count of 5.0 log10 CFU/cm2. Counts of pathogens, APC, coliforms, and E. coli were conducted before and after applying the dehairing treatment. S. Typhimurium and E. coli O157:H7 populations were significantly reduced from initial numbers (5.1 to 5.3 log10 CFU/cm2) to levels below the detection limit of 0.5 log10 CFU/cm2 after Chemical dehairing. APC, coliforms, and E. coli counts were also reduced significantly after dehairing, with reductions of 3.4 for APC, 3.9 for coliforms, and >4.3 log10 CFU/cm2 for other E. coli strains. Since the hide is a major source of fecal contamination of beef carcass surfaces, Chemical dehairing may be beneficial in reducing overall contamination of carcasses.

Microbiological Quality of Fresh Blue Crabmeat, Clams and Oysters

1983 ◽  
Vol 46 (11) ◽  
pp. 978-981 ◽  
Author(s):  
B. A. WENTZ ◽  
A. P. DURAN ◽  
A. SWARTZENTRUBER ◽  
A. H. SCHWAB ◽  
R. B. READ
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Microbiological Quality ◽  
Fecal Coliforms ◽  
Geometric Means ◽  
Colony Forming Units ◽  
Plate Counts ◽  
The Mean ◽  
Eastern Oysters

The microbiological quality of fresh blue crabmeat, soft- and hardshell clams and shucked Eastern oysters was determined at the retail (crabmeat, oysters) and wholesale (clams) levels. Geometric means of aerobic plate counts incubated at 35°C were: blue crabmeat 140,000 colony-forming units (CFU)/g, hardshell clams, 950 CFU/g, softshell clams 680 CFU/g and shucked Eastern oysters 390,000 CFU/g. Coliform geometric means ranged from 3,6/100 g for hardshell clams to 21/g for blue crabmeat. Means for fecal coliforms or Escherichia coli ranged from <3/100 g for clams to 27/100 g for oysters, The mean Staphylococcus aureus count in blue crabmeat was 10/g.

scholarly journals Comparison of materials used for cleaning equipment in retail food premises, and of two methods for the enumeration of bacteria on cleaned equipment and work surfaces

1970 ◽  
Vol 68 (2) ◽  
pp. 221-232 ◽  
Author(s):  
R. J. Gilbert
Keyword(s):  
Control Method ◽  
Field Trials ◽  
Surface Sampling ◽  
Step Procedure ◽  
Cleaning Equipment ◽  
Before And After ◽  
Plate Counts ◽  
Self Service ◽  
Materials Used ◽  
Retail Food

SUMMARYThere is no official scheme for testing disinfectants and detergent/disinfectants for use in the retail food trade and few recommended procedures have been given for the cleaning of equipment with these agents. Therefore, field trials were carried out in a large self-service store. Comparisons were made of the various cleaning efficiencies, as determined by bacterial plate counts, of detergent and disinfectant solutions and machine cleaning oils applied with either clean cloths or disposable paper towels to items of equipment. The most satisfactory results were always obtained when anionic detergent (0·75 % w/v) and hypochlorite (200 p.p.m. available chlorine) solutions were applied in a ‘two-step’ procedure.Tests were made to compare the calcium alginate swab-rinse and the agar sausage (Agaroid) techniques for the enumeration of bacteria on stainless steel, plastic, formica and wooden surfaces before and after a cleaning process. Although recovery rates were always greater by the swab-rinse technique, the agar sausage technique was considered to be a useful routine control method for surface sampling.

scholarly journals The quantitative bacteriology of some commercial bivalve shellfish entering British markets

1975 ◽  
Vol 74 (3) ◽  
pp. 431-440 ◽  
Author(s):  
P. A. Ayres
Keyword(s):  
Public Health ◽  
Escherichia Coli ◽  
Health Risk ◽  
E Coli ◽  
Accepted Standard ◽  
Plate Counts ◽  
Bivalve Shellfish ◽  
Faecal Streptococci ◽  
Specific Illness

SUMMARYIncidents of non-specific illness associated with the consumption of oysters have highlighted the lack of published information on the bacteriology of shellfish suitable for consumption. Investigations showed that the majority of molluscan shellfish entering English markets conform to the accepted standard of less than 5 Escherichia coli/ml. tissue. The numbers of E. coli were related to the sanitary quality of the growing area but no relation could be established between numbers of E. coli and coliforms, faecal streptococci or Clostridium welchii. The numbers of non-specific bacteria varied considerably but shellfish from sources associated with non-specific illness yielded relatively high counts at 37° C. The results showed that there was no justification for a standard based on total plate counts, which often exceeded 106/g. Such a standard would have to be coupled with spoilage or the incidence of non-specific illness. The relation between the numbers of non-specific bacteria growing at 20 and 37° C. appears to be a useful measure for assessing the likelihood that raw shellfish are a public health risk.

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.

A Comparison of Hand Washing Techniques To Remove Escherichia coli and Caliciviruses under Natural or Artificial Fingernails

2003 ◽  
Vol 66 (12) ◽  
pp. 2296-2301 ◽  
Author(s):  
CHIA-MIN LIN ◽  
FONE-MAO WU ◽  
HOI-KYUNG KIM ◽  
MICHAEL P. DOYLE ◽  
BARRY S. MICHAELS ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Tap Water ◽  
Hand Washing ◽  
Microbial Populations ◽  
Liquid Soap ◽  
E Coli ◽  
Hand Sanitizer ◽  
Before And After ◽  
Escherichia Coli Jm109 ◽  
Viral Indicators

Compared with other parts of the hand, the area beneath fingernails harbors the most microorganisms and is most difficult to clean. Artificial fingernails, which are usually long and polished, reportedly harbor higher microbial populations than natural nails. Hence, the efficacy of different hand washing methods for removing microbes from natural and artificial fingernails was evaluated. Strains of nonpathogenic Escherichia coli JM109 and feline calicivirus (FCV) strain F9 were used as bacterial and viral indicators, respectively. Volunteers with artificial or natural nails were artificially contaminated with ground beef containing E. coli JM109 or artificial feces containing FCV. Volunteers washed their hands with tap water, regular liquid soap, antibacterial liquid soap, alcohol-based hand sanitizer gel, regular liquid soap followed by alcohol gel, or regular liquid soap plus a nailbrush. The greatest reduction of inoculated microbial populations was obtained by washing with liquid soap plus a nailbrush, and the least reduction was obtained by rubbing hands with alcohol gel. Lower but not significantly different (P > 0.05) reductions of E. coli and FCV counts were obtained from beneath artificial than from natural fingernails. However, significantly (P ≤ 0.05) higher E. coli and FCV counts were recovered from hands with artificial nails than from natural nails before and after hand washing. In addition, microbial cell numbers were correlated with fingernail length, with greater numbers beneath fingernails with longer nails. These results indicate that best practices for fingernail sanitation of food handlers are to maintain short fingernails and scrub fingernails with soap and a nailbrush when washing hands.

Multiplex Quantitative PCR Assays for the Detection and Quantification of the Six Major Non-O157 Escherichia coli Serogroups in Cattle Feces†

2016 ◽  
Vol 79 (1) ◽  
pp. 66-74 ◽  
Author(s):  
P. B. SHRIDHAR ◽  
L. W. NOLL ◽  
X. SHI ◽  
B. AN ◽  
N. CERNICCHIARO ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Quantitative Pcr ◽  
Foodborne Pathogens ◽  
Virulence Genes ◽  
Target Genes ◽  
Culture Methods ◽  
Fecal Samples ◽  
E Coli ◽  
Cattle Feces ◽  
Before And After

ABSTRACT Shiga toxin–producing Escherichia coli (STEC) serogroups O26, O45, O103, O111, O121, and O145, called non-O157 STEC, are important foodborne pathogens. Cattle, a major reservoir, harbor the organisms in the hindgut and shed them in the feces. Although limited data exist on fecal shedding, concentrations of non-O157 STEC in feces have not been reported. The objectives of our study were (i) to develop and validate two multiplex quantitative PCR (mqPCR) assays, targeting O-antigen genes of O26, O103, and O111 (mqPCR-1) and O45, O121, and O145 (mqPCR-2); (ii) to utilize the two assays, together with a previously developed four-plex qPCR assay (mqPCR-3) targeting the O157 antigen and three virulence genes (stx1, stx2, and eae), to quantify seven serogroups and three virulence genes in cattle feces; and (iii) to compare the three mqPCR assays to a 10-plex conventional PCR (cPCR) targeting seven serogroups and three virulence genes and culture methods to detect seven E. coli serogroups in cattle feces. The two mqPCR assays (1 and 2) were shown to be specific to the target genes, and the detection limits were 4 and 2 log CFU/g of pure culture–spiked fecal samples, before and after enrichment, respectively. A total of 576 fecal samples collected from a feedlot were enriched in E. coli broth and were subjected to quantification (before enrichment) and detection (after enrichment). Of the 576 fecal samples subjected, before enrichment, to three mqPCR assays for quantification, 175 (30.4%) were quantifiable (≥4 log CFU/g) for at least one of the seven serogroups, with O157 being the most common serogroup. The three mqPCR assays detected higher proportions of postenriched fecal samples (P < 0.01) as positive for one or more serogroups compared with cPCR and culture methods. This is the first study to assess the applicability of qPCR assays to detect and quantify six non-O157 serogroups in cattle feces and to generate data on fecal concentration of the six serogroups.

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