Lethality of Heat to Escherichia coli 0157:H7: D-Value and Z-Value Determinations in Ground Beef

1991 ◽  
Vol 54 (10) ◽  
pp. 762-766 ◽  
Author(s):  
J. ERIC LINE ◽  
ALFRED R. FAIN ◽  
ALICE B. MORAN ◽  
L. MICHELE MARTIN ◽  
RICHARD V. LECHOWICH ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Ground Beef ◽  
Plate Count ◽  
Ground Meat ◽  
Plate Count Agar ◽  
Death Time ◽  
Lean Beef ◽  
Z Value ◽  
D Values ◽  
D Value

D-values and z-values were determined for lean (2.0% fat) and fatty (30.5% fat) ground beef inoculated with approximately 107 Escherichia coli 0157:H7 cells per g. Inoculated ground meat was sealed in glass thermal death time tubes which were completely immersed in a circulating water bath and held at prescribed temperatures for predetermined lengths of time. Survival was determined by enumeration on plate count agar (PCA) containing 1% sodium pyruvate and by the 2-h indole test of Lee and McClain (7). D-values for fatty ground beef exceeded those for lean ground beef at the temperatures tested. D-values for lean and fatty ground beef at 125°F were 78.2 and 115.5 min, respectively, as enumerated on PCA plus pyruvate. D-values at 135°F were 4.1 and 5.3 min for lean and fatty beef. At 145°F D-values were determined to be 0.3 and 0.5 min. D-values calculated from 2-h indole test data for lean and fatty ground beef at 125°F were 80.1 and 121.0 min, respectively. D-values at 135°F were 4.0 and 7.4 min for lean and fatty beef and at 145°F a D-value of 0.2 min was calculated for lean beef only, due to insufficient survival of E. coli 0157:H7 in fatty beef at this temperature. The z-values determined for lean beef and fatty beef using PCA were 8.3 and 8.4°F respectively. The z-value for lean beef using the 2-h indole data was 7.8°F. No z-value for fatty beef using 2-h indole data could be determined.

Lethality of Heat to Listeria monocytogenes Scott A: D-Value and Z-Value Determinations in Ground Beef and Turkey

1991 ◽  
Vol 54 (10) ◽  
pp. 756-761 ◽  
Author(s):  
ALFRED R. FAIN ◽  
J. ERIC LINE ◽  
ALICE B. MORAN ◽  
L. MICHELE MARTIN ◽  
RICHARD V. LECHOWICH ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Ground Beef ◽  
Ground Meat ◽  
Circulating Water ◽  
Death Time ◽  
Lean Beef ◽  
Z Value ◽  
D Values ◽  
Thermal Death Time ◽  
D Value

D-Values and z-values for Listeria monocytogenes strain Scott A were determined in lean (2.0% fat) and fatty (30.5%) ground beef inoculated with approximately 107cells/g. Inoculated ground meat was sealed in glass thermal death time tubes which were completely immersed in a circulating water bath and held at prescribed temperatures for predetermined lengths of time. Survival was determined by enumeration on Columbia CNA agar base containing 1% sodium pyruvate with a CNA + 4% horse blood overlay (CBNA) and on Listeria Plating Medium (LPM). D-values for L. monocytogenes in lean and fatty ground beef at 125° were 81.3 and 71.1 min, respectively, as enumerated on CBNA plus pyruvate. D-values at 135°F were 2.6 and 5.8 min in lean and fatty beef. At 145°F, D-values were determined to be 0.6 and 1.2 min. D-values calculated from LPM recovery data from fatty ground beef at 125°F were 56.1 and 34.5 min, respectively. D-values at 135°F were 2.4 and 4.6 min in lean and fatty beef. At 145°F a D-value of 0.5 min was calculated in lean beef and a D-value of 1.1 min was determined in fatty beef. The z-values determined in lean beef and fatty beef using CBNA recovery data were 9.3 and 11.4°F, respectively. The z-value in lean beef using LPM recovery data was 9.8°F. The z-value in fatty beef using LPM recovery data was 13.2°F. A D-value for ground turkey meat at 160°F could not be determined under the conditions of this study. Problems encountered are discussed.

Thermal Inactivation of Escherichia coli O157: H7, Salmonella senftenberg, and Enzymes with Potential as Time-Temperature Indicators in Ground Beef

1997 ◽  
Vol 60 (5) ◽  
pp. 471-475 ◽  
Author(s):  
ALICIA ORTA-RAMIREZ ◽  
JAMES F. PRICE ◽  
YIH-CHIH HSU ◽  
GIRIDARAN J. VEERAMUTHU ◽  
JAMIE S. CHERRY-MERRITT ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Thermal Inactivation ◽  
Ground Beef ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Triose Phosphate ◽  
Beef Products ◽  
Z Value ◽  
D Values ◽  
Salmonella Senftenberg

The USDA has established processing schedules for beef products based on the destruction of pathogens. Several enzymes have been suggested as potential indicators of heat processing. However, no relationship between the inactivation rates of these enzymes and those of pathogenic microorganisms has been determined. Our objective was to compare the thermal inactivation of Escherichia coli O157:H7 and Salmonella senftenberg to those of endogenous muscle proteins. Inoculated and noninoculated ground beef samples were heated at four temperatures for predetermined intervals of time in thermal-death-time studies. Bacterial counts were determined and enzymes were assayed for residual activity. The D values for E. coli O157:H7 were 46.10, 6.44, 0.43, and 0.12 min at 53, 58, 63, and 68°C, respectively, with a z value of 5.60°C. The D values for S. senftenberg were 53.00, 15.17, 2.08, and 0.22 min at 53, 58, 63, and 68°C, respectively, with a z value of 6.24°C. Apparent D values at 53, 58, 63, and 68°C were 352.93, 26.31, 5.56, and 3.33 min for acid phosphatase; 6968.64, 543.48, 19.61, and 1.40 min for lactate dehydrogenase; and 3870.97, 2678.59, 769.23, and 42.92 min for peroxidase; with z values of 7.41,3.99, and 7.80°C, respectively. Apparent D values at 53, 58, 63, and 66°C were 325.03, 60.07, 3.07, and 1.34 min for phosphoglycerate mutase; 606.72, 89.86, 4.40, and 1.28 min for glyceraldehyde-3-phosphate dehydrogenase; and 153.06, 20.13, 2.25, and 0.74 min for triose phosphate isomerase; with z values of 5.18, 4.71, and 5.56°C, respectively. The temperature dependence of triose phosphate isomerase was similar to those of both E. coli O157 :H7 and S. senftenberg, suggesting that this enzyme could be used as an endogenous time-temperature indicator in beef products.

scholarly journals Antibiogram Profiling and Thermal Inactivation of Staphylococcus aureus and Escherichia coli Isolated from Milk of Dharan, Nepal

2020 ◽  
pp. 81-87
Author(s):  
Susmita Phattepuri ◽  
Prince Subba ◽  
Arjun Ghimire ◽  
Shiv Nandan Sah
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Thermal Inactivation ◽  
Total Coliform ◽  
Plate Count ◽  
Diffusion Method ◽  
E Coli ◽  
Coliform Count ◽  
Z Value ◽  
D Values

Milk is an excellent medium for the growth of many bacteria. This study aimed to determine antibiotic profiling and thermal inactivation of Staphylococcus aureus and Escherichia coli isolated from raw milk of Dharan. Total viable count, total Staphylococcal count, and total coliform count were carried out by conventional microbiological methods. Identification was done on the basis of Gram staining and biochemical tests. The antibiotic susceptibility test of the isolates carried out by the modified Kirby-Baur disc diffusion method. Thermal inactivation of S. aureus and E. coli were carried out by subjecting to thermal treatment in a water bath. Total plate count ranged from 204×104 CFU/mL to 332×105 CFU/mL. Total staphylococcal count and total coliform count ranged from 14×105 CFU/mL to 8×106 CFU/mL and 11×104 CFU/mL to 3×106 CFU/mL respectively. S. aureus showed an increasing resistance patterns towards Ampicillin, Cefotixin, Carbenicillin and Cefotaxime. Ciprofloxacin, Erythromycin, Amikacin, Gentamycin, Azithromycin, and Chloramphenicol were found to be effective against S. aureus. All the E. coli isolates were resistant to Ampicillin and least resistant to Cefotixin. Chloramphenicol, Amikacin, Azithromycin, and Nalidixic acid were found highly effective to E. coli. The D-values for S. aureus at 56°C, 58°C and 60°C were 1.36 min, 1.19 min, and 1.09 min respectively. The Z-value was 14.92°C. While D-values were obtained as 0.98 min, 0.75 min, and 0.57 min for E. coli at 56° C, 58° C and 60° C respectively, and Z-value was 9.75° C. Hence, S. aureus was found to be more heat resistant than E. coli.

Carvacrol and Cinnamaldehyde Facilitate Thermal Destruction of Escherichia coli O157:H7 in Raw Ground Beef†

2008 ◽  
Vol 71 (8) ◽  
pp. 1604-1611 ◽  
Author(s):  
VIJAY K. JUNEJA ◽  
MENDEL FRIEDMAN
Keyword(s):  
Escherichia Coli ◽  
Ground Beef ◽  
Inactivation Kinetics ◽  
Escherichia Coli O157 ◽  
Internal Temperature ◽  
Circulating Water ◽  
Critical Control Points ◽  
Thermal Death ◽  
D Values ◽  
D Value

The heat resistance of a four-strain mixture of Escherichia coli O157:H7 in raw ground beef in both the absence and presence of the antimicrobials carvacrol and cinnamaldehyde was tested at temperatures ranging from 55 to 62.5°C. Inoculated meat packaged in bags was completely immersed in a circulating water bath, cooked for 1 h to an internal temperature of 55, 58, 60, or 62.5°C, and then held for predetermined lengths of time ranging from 210 min at 55°C to 5 min at 62.5°C. The surviving bacteria were enumerated by spiral plating onto tryptic soy agar overlaid with sorbitol MacConkey agar. Inactivation kinetics of the pathogens deviated from first-order kinetics. D-values (time for the bacteria to decrease by 90%) in the control beef ranged from 63.90 min at 55°C to 1.79 min at 62.5°C. D-values determined by a logistic model ranged from 43.18 min (D1, the D-value of a major population of surviving cells) and 89.84 min (D2, the D-value of a minor subpopulation) at 55°C to 1.77 (D1) and 0.78 min (D2) at 62.5°C. The thermal death times suggested that to achieve a 4-D reduction, contaminated processed ground beef should be heated to an internal temperature of 60°C for at least 30.32 min. Significantly increased sensitivity to heat (P < 0.05) was observed with the addition and/or increasing levels of carvacrol or cinnamaldehyde from 0.5 to 1.0%. The observed thermal death times may facilitate the design of acceptance limits at critical control points for ground beef at lower times and temperatures of heating.

Thermal Destruction of Escherichia coli O157:H7 in Sous-Vide Cooked Ground Beef as Affected by Tea Leaf and Apple Skin Powders†

2009 ◽  
Vol 72 (4) ◽  
pp. 860-865 ◽  
Author(s):  
VIJAY K. JUNEJA ◽  
M. L. BARI ◽  
Y. INATSU ◽  
S. KAWAMOTO ◽  
MENDEL FRIEDMAN
Keyword(s):  
Escherichia Coli ◽  
Ground Beef ◽  
Inactivation Kinetics ◽  
Skin Extract ◽  
Escherichia Coli O157 ◽  
Circulating Water ◽  
Sous Vide ◽  
D Values ◽  
A Minor ◽  
D Value

We investigated the heat resistance of a four-strain mixture of Escherichia coli O157:H7 in raw ground beef in both the absence and presence of white and green tea powders and an apple skin extract. Inoculated meat was cooked using the sous-vide technique, i.e., the meat was packaged in sterile bags and completely immersed in a circulating water bath at low temperature for a period of time. The bags were cooked for 1 h to an internal temperature of 55, 58, 60, or 62.5°C, and then held from 240 min at 55°C to 10 min at 62.5°C. The surviving bacteria were enumerated by spiral plating onto tryptic soy agar overlaid with sorbitol-MacConkey agar. Inactivation kinetics of the pathogens deviated from first-order kinetics. D-values (time, in minutes, required for the bacteria to decrease by 90%) in the control beef ranged from 67.79 min at 55°C to 2.01 min at 62.5°C. D-values determined by a logistic model ranged from 36.22 (D1, the D-value of a major population of surviving cells) and 112.79 (D2, the D-value of a minor subpopulation) at 55°C to 1.39 (D1) and 3.00 (D2) at 62.5°C. A significant increase (P < 0.05) in the sensitivity of the bacteria to heat was observed with the addition of 3% added antimicrobials. D-value reductions of 62 to 74% were observed with apple powder and 18 to 58% with tea powders. Thermal death times from this study will assist the retail food industry to design cooking regimes that ensure the safety of beef contaminated with E. coli O157:H7.

Thermal Inactivation of Shiga Toxin–Producing Escherichia coli in Ground Beef with Varying Fat Content

2018 ◽  
Vol 81 (6) ◽  
pp. 986-992 ◽  
Author(s):  
JAGPINDER S. BRAR ◽  
JOLENA N. WADDELL ◽  
MATTHEW BAILEY ◽  
SYDNEY CORKRAN ◽  
CARMEN VELASQUEZ ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Thermal Inactivation ◽  
Ground Beef ◽  
Fat Content ◽  
Water Bath ◽  
Survival Curves ◽  
Laboratory Medium ◽  
D Values ◽  
D Value

ABSTRACT Decimal reduction time (D-value) was calculated for six non-O157 Shiga toxin–producing Escherichia coli (STEC) in a laboratory medium and ground beef. For the laboratory medium, an overnight culture of each strain of STEC was divided into 10-mL sample bags and heated in a water bath for a specific time on the basis of the temperatures. Survival curves were generated by plotting the surviving bacterial population against time, and a linear-log primary model was used to estimate the D-values from survival curves. The z-values (the temperature raised to reduce the D-value by one-tenth) were calculated by plotting the log D-values against temperature. Similarly, for ground beef, six fat contents, 5, 10, 15, 20, 25, and 30% of ground beef were formulated for this study. Inoculated meat was divided into 5-g pouches and submerged in a water bath set at specific temperatures (55, 60, 65, 68, and 71.1°C). The average D-value for these strains in a laboratory medium was 17.96 min at 55°C, which reduced significantly (P < 0.05) to 1.58 min at 60°C, and then further reduced (P < 0.05) to 0.46 min at 65°C. In ground beef, a negative correlation (P < 0.05) between fat content of ground beef and D-values was observed at 55°C. However, at temperatures greater than 60°C, there was no impact (P > 0.05) of fat content of ground beef on the thermal resistance of non-O157 STECs. Irrespective of the fat content of ground beef, the D-values ranged from 15.93 to 11.69, 1.15 to 1.12, and 0.14 to 0.09 min and 0.05 at 55, 60, 65, and 68°C, respectively. The data generated from this study can be helpful for the meat industry to develop predictive models for thermal inactivation of non-O157 STECs in ground beef with varying fat content.

Comparison of β-Glucuronidase and Indole-Based Direct Plating Methods for Enumerating Escherichia coli in Artificially Inoculated Ground Meats

1990 ◽  
Vol 53 (11) ◽  
pp. 933-935 ◽  
Author(s):  
ELON W. FRAMPTON ◽  
LAWRENCE RESTAINO ◽  
NANCY BLASZKO
Keyword(s):  
Escherichia Coli ◽  
Ground Beef ◽  
Plate Count ◽  
Most Probable Number ◽  
Probable Number ◽  
E Coli ◽  
Glucuronidase Activity ◽  
Plate Count Agar ◽  
Significant Difference ◽  
Indole Production

Peptone tergitol glucuronide (PTG) agar containing 4-methylumbelliferyl-β-D glucuronide (MUG) (for β-glucuronidase activity), the Holbrook, Anderson, Baird-Parker (HABP) method (for detecting indole production), and the standard 3-tube most probable number (MPN) method were compared with plate count agar (PCA) for enumerating three strains of unstressed Escherichia coli artificially inoculated into ground beef and chicken at 1–6 × 106 cells/g. No significant difference (P>0.05) was determined between PTG agar and PCA in the recovery of E. coli. The MPN method enumerated a significantly greater (P<0.05) number of E. coli cells than PCA. Compared with PCA, the HABP method recovered a significantly lower (P<0.05) number of E. coli cells from chicken, whereas no significant difference (P>0.05) was obtained with ground beef. When combining all data from chicken and beef, the recovery of E. coli cells by the HABP method was also significantly lower (P<0.05). Overall, based on the enumeration of E. coli on PCA, the HABP method, PTG agar, and MPN method recovered 57, 102, and 144%, respectively.

Survival of Listeria monocytogenes in Ground Beef or Liver During Storage at 4 and 25°C.

1989 ◽  
Vol 52 (6) ◽  
pp. 379-383 ◽  
Author(s):  
LEORA A. SHELEF
Keyword(s):  
Listeria Monocytogenes ◽  
Ground Beef ◽  
Plate Count ◽  
C Cells ◽  
Ground Meat ◽  
Potassium Tellurite ◽  
Plate Count Agar ◽  
Natural Microflora ◽  
Survival And Growth ◽  
Selective Environment

Survival and growth of three Listeria monocytogenes strains (Scott A, Brie-1, and ATCC 35152) were studied in ground beef or liver during storage from freshness to spoilage at 4 and 25°C. Cells were enumerated on Plate Count Agar, Trypticase Soy Agar, and selective media, including McBride Listeria Agar (MLA), Cyclohexanedione Nalidixic Acid Phenylethanol Agar (CNPA), LiCl Phenylethanol Moxalactam Agar (LPM), and LPM with potassium tellurite (LPMT). Aerobic natural microflora in the fresh uninoculated samples ranged from 102 to 104 CFU/g, and L. monocytogenes inocula were ca. 103 or 105 CFU/g. Total aerobes after 2 weeks at 4°C were >108 or >107/g in meat or liver respectively, while recovered numbers of L. monocytogenes remained unchanged during a storage of over 30 d in either ground meat or liver. Samples stored at 25°C confirmed recovery but absence of multiplication of the organism. LPM or LPMT provided the best selective environment for direct plating of meat. Despite differences in composition and spoilage pattern of meat and liver, no difference was observed in the fate of L. monocytogenes in these foods.

scholarly journals Cemaran bakteri pada makanan pempek produksi rumah tangga dan pabrik pengolah makanan

2020 ◽  
Vol 12 (2) ◽  
pp. 193-200
Author(s):  
Joko Sapto Pramono ◽  
Mustaming Mustaming ◽  
Dewi Samara Putri
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Random Sampling ◽  
Plate Count ◽  
Plate Count Agar ◽  
Colony Counter

Pempek merupakan makanan tradisional yang berasal dari Palembang. Makanan ini diproduksi oleh industri rumah tangga maupun pabrik pengolah makanan. Olahan ikan ini beresiko dicemari oleh bakteri Escherichia coli, Salmonella, dan Staphylococcus aureus. Penelitian ini bertujuan untuk mengetahui cemaran bakteri pada pempek yang dijual di pasaran kota Samarinda. Jenis penelitian yang digunakan adalah penelitian laboratorium. Teknik sampling yang digunakan yaitu random sampling. Jumlah sampel yang diperoleh sebanyak 20 sampel pempek, 10 sampel produksi industri rumah tangga dan 10 sampel produksi pabrik. Sampel kemudian dibawa ke laboratorium dan dilakukan pemeriksaan jumlah koloni dengan menggunakan colony counter. Hasil penghitungan Angka Lempeng Total (ALT) pada media Plate Count Agar (PCA) menunjukkan bahwa sebanyak 18 sampel (90%) yang terdiri dari 10 sampel pempek produksi pabrik dan 8 sampel pempek produksi rumahan mengandung cemaran mikroba yang tinggi (> 5x 104). Masyarakat disarankan memasak pempek hingga matang sebelum mengkonsumsi baik pempek produksi pabrik maupun produksi rumahan agar terhindar dari resiko cemaran bakteri patogen. Catatan PenerbitPoltekkes Kemenkes Kendari menyatakan tetap netral sehubungan dengan klaim dari perspektif atau buah pikiran yang diterbitkan dan dari afiliasi institusional manapun. PendanaanKajian terlaksana atas pembiayaan sukarela peneliti. Konflik KepentinganPara penulis menyatakan bebas dari konflik kepentingan. Berbagi DataData hasil kajian tersedia melalui permohonan kepada penulis koresponden. Kontribusi PenulisPara penulis tidak mendeklarasikan setiap kontribusinya.

Evaluation of Dichloran-Rose Bengal Agar for Enumeration of Fungi in Foods1

1985 ◽  
Vol 48 (7) ◽  
pp. 562-563 ◽  
Author(s):  
J. A. KOBURGER ◽  
F. C. CHANG ◽  
C. I. WEI
Keyword(s):  
Rose Bengal ◽  
Bacterial Contamination ◽  
Plate Count ◽  
Corn Meal ◽  
Ground Meat ◽  
Plate Count Agar ◽  
Standard Procedures

Samples of flour, corn meal, ground meat and carrots were analyzed by standard procedures for presence of fungi using both Dichloran-Rose Bengal (DRBC) and Plate Count agar with antibiotics. Bacterial contamination was so extensive with ground meat and carrot samples on DRBC that meaningful fungal counts could not be obtained. Therefore, DRBC is not recommended for routine enumeration of fungi in foods.

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