Fate of Selected Pathogens Inoculated into Foods Prepared in Slow Cookers1,2

1979 ◽  
Vol 42 (11) ◽  
pp. 872-876 ◽  
Author(s):  
J. RITTER ◽  
J. O'LEARY ◽  
B. E. LANGLOIS
Keyword(s):  
Staphylococcus Aureus ◽  
Low Temperature ◽  
Salmonella Typhimurium ◽  
Clostridium Perfringens ◽  
Health Hazard ◽  
Green Bean ◽  
Vegetative Cells ◽  
Salmonella Choleraesuis ◽  
Navy Beans ◽  
The Mean

Staphylococcus aureus, Clostridium perfringens. Salmonella choleraesuis, and Salmonella typhimurium were inoculated (108 cells or spores) into two slow cookers containing green bean casserole, baked navy beans, chicken cacciatore, barbecued ribs or pork pot roast, and their fate determined after cooking. Heating patterns also were determined at three positions inside the two cookers. None of the foods cooked in either of the slow cookers contained detectable levels of S. aureus or salmonellae. The similarity between C. perfringens vegetative and spore counts indicate that only spores were present in the cooked foods. Except for the green bean casserole cooked using a low temperature setting, cooking resulted in a 0.44–1.67 and 0.36–1.54 log count reduction, respectively, of vegetative cells and spores of C. perfringens. Counts of vegetative cells and spores after cooking the green bean casserole were approximately .18 and .30 log counts higher than the uncooked counts. The mean times for the coldest areas in Cooker A to reach 50 C were 2.57 and 0.97 h, respectively, for the low (80 watts) and high (160 watts) temperature settings. The mean times for the coldest areas in Cooker B (removable liner) to reach 50 C were 2.35 and 0.52 h for the low (130 watts) and high (260 watts) temperature settings, respectively. Results suggest that when the recommended quantities of ingredients are used and the proper cooking procedure followed, foods prepared in the slow cookers studied do not present a health hazard.

Fate of Pathogens Inoculated onto Vacuum-Packaged Sliced Hams to Simulate Contamination During Packaging1

1979 ◽  
Vol 42 (6) ◽  
pp. 464-469 ◽  
Author(s):  
M. E. STILES ◽  
L.-K. NG
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Salmonella Typhimurium ◽  
Bacillus Cereus ◽  
Clostridium Perfringens ◽  
Subsequent Treatment ◽  
Vacuum Packaging ◽  
E Coli ◽  
Survival And Growth ◽  
And Staphylococcus Aureus

Ham and chopped ham from two manufacturers were contaminated with five enteropathogens: Bacillus cereus, Clostridium perfringens, Escherichia coli, Salmonella typhimurium and Staphylococcus aureus, at time of slicing and vacuum-packaging, to simulate contamination by manufacturer. Subsequent treatment of the samples, representing sound and undesirable retail handling and consumer use conditions, indicated marked differences in the fate of the pathogens between these products and within product type between the two manufacturers. Greatest differences were observed between the chopped ham products. All pathogens, except C. perfringens, grew actively in fresh ham and chopped ham with abusive holding at 30 and 21 C. After storage at 4 or 10 C for 30 days, B. cereus and C. perfringens were no longer detected, even after subsequent holding at 30 or 21 C for 24 h. E. coli survival and growth was variable, S. typhimurium survived well and grew under some conditions and S. aureus was generally inhibited at high levels of competition.

Bacterial Cell Characteristics and Conditions Influencing Their Adhesion to Poultry Skin

1985 ◽  
Vol 48 (9) ◽  
pp. 803-807 ◽  
Author(s):  
H. S. LILLARD
Keyword(s):  
Staphylococcus Aureus ◽  
Salmonella Typhimurium ◽  
Clostridium Perfringens ◽  
Constant Pressure ◽  
Linear Increase ◽  
Bacterial Attachment ◽  
Sample Type ◽  
Proteus Vulgaris ◽  
Gram Negative ◽  
Salmonella Gallinarum

Conflicting reports appear in the literature regarding attachment of flagellated and nonflagellated bacteria to poultry skin. The following parameters which may influence bacterial attachment were examined: (a) sample type and size; (b) skin from fully processed and scalded but uneviscerated broilers; (c) skin from hard- and soft-scalded broilers; and (d) potentially variable tap rinse and constant pressure spray wash (50 psi). Gram-positive and gram-negative, flagellated and nonflagellated bacteria were used in suspension fluids (Salmonella typhimurium, Salmonella gallinarum, Proteus vulgaris, Pseudomonas fluoresces, Clostridium perfringens, Staphylococcus aureus and a nonflagellated species of Micrococcus). Results showed that none of the variables tested affected the ability of bacteria to adhere to poultry skin in 0.25 min. All species tested adhered to skin, and there was a generally linear increase in rate of attachment with time (0.25 to 60 min) following exposure of poultry skin to suspending fluid. It was concluded that nonflagellated bacteria attach as readily as flagellated bacteria under the same controlled conditions.

Sensitivity of Foodborne Bacteria (Spoilage and Pathogenic) to a Methanol-Acetone Extract of Milk Fermented by Streptococcus thermophilus

1987 ◽  
Vol 50 (10) ◽  
pp. 812-814 ◽  
Author(s):  
A. SIKES ◽  
T. HILTON
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Fluorescens ◽  
Clostridium Perfringens ◽  
Salmonella Enteritidis ◽  
Streptococcus Thermophilus ◽  
Fermented Milk ◽  
Acetone Extract ◽  
Foodborne Bacteria ◽  
Test Organisms ◽  
The Mean

Effects of an inhibitory methanol-acetone (MA) extract of Streptococcus thermophilus-fermented milk was tested on growth of Salmonella enteritidis, two strains of Staphylococcus aureus (types A and E), two strains of Clostridium perfringens (types A and C) and Pseudomonas fluorescens. Each organism was tested at three levels of the extract, e.g., 250, 500 and 1000 ppm. Results indicated that the degree of sensitivity among the test organisms varied. C. perfringens (C) was the most sensitive, with a mean % inhibition (average % inhibition over the three MA extract concentrations) of 73.3, while S. enteritidis was the least sensitive (mean % inhibition = 51.8) to the extract. The differences between the mean % inhibition of P. fluorescens (65.4), S. aureus (A) (64.8), and C. perfringens (A) (62.2) were not significant (P>0.05); however, the sensitivity of these three organisms to the extract was significantly less (P<0.05) than C. perfringens (C) but significantly greater (P<0.05) than S. aureus (E) and S. enteritidis.

Survival of Pathogens on Modified-Atmosphere-Packaged Shredded Carrot and Cabbage

1997 ◽  
Vol 60 (11) ◽  
pp. 1347-1350 ◽  
Author(s):  
MARY J. FINN ◽  
MARY E. UPTON
Keyword(s):  
Carbon Dioxide ◽  
Staphylococcus Aureus ◽  
Salmonella Typhimurium ◽  
Clostridium Perfringens ◽  
Listeria Innocua ◽  
Modified Atmosphere ◽  
Polypropylene Film ◽  
Direct Plating ◽  
Selective Media ◽  
Selective Enrichment

The populations changes of Staphylococcus aureus, Bacillus cereus, Listeria innocua, Salmonella typhimurium and Clostridium perfringens inoculated separately onto modified-atmosphere-packaged fresh shredded carrot and cabbage was investigated. Shredded carrot and cabbage (25-g amounts) was packaged in polypropylene film (35 μm thick) and stored at 7°C. The modified atmosphere within the packs was produced naturally by respiration with levels of carbon dioxide reaching >25% and levels of oxygen falling to <1% following 8 days of storage. Populations of pathogens were enumerated by direct plating on selective media on the day of inoculation and 2, 4, 6, and 8 days postinoculation. The presence or absence of S. typhimurium was determined following preenrichment and selective enrichment steps: this species was found to be absent following 2 days of storage at 7°C. Statistically significant decreases (P < 0.05) in numbers of all other pathogens detected on day 0 and day 8 were observed. Pathogens were not detected on these vegetables in uninoculated packs.

Validation of Bacon Processing Conditions To Verify Control of Clostridium perfringens and Staphylococcus aureus

2005 ◽  
Vol 68 (9) ◽  
pp. 1831-1839 ◽  
Author(s):  
PETER J. TAORMINA ◽  
GENE W. BARTHOLOMEW
Keyword(s):  
Staphylococcus Aureus ◽  
Clostridium Perfringens ◽  
Meat Products ◽  
Thermal Conditions ◽  
Laboratory Scale ◽  
Vegetative Cells ◽  
Liquid Smoke ◽  
Ground Pork ◽  
Fully Cooked ◽  
And Staphylococcus Aureus

It is unclear how rapidly meat products, such as bacon, that have been heat treated but not fully cooked should be cooled to prevent the outgrowth of spore-forming bacterial pathogens and limit the growth of vegetative cells. Clostridium perfringens spores and vegetative cells and Staphylococcus aureus cells were inoculated into ground cured pork bellies with and without 1.25% liquid smoke. Bellies were subjected to the thermal profiles of industrial smoking to 48.9°C (120°F) and normal cooling of bacon (3 h) as well as a cooling phase of 15 h until the meat reached 7.2°C (45°F). A laboratory-scale bacon smoking and cooling operation was also performed. Under normal smoking and cooling thermal conditions, growth of C. perfringens in ground pork bellies was <1 log regardless of smoke. Increase of S. aureus was 2.38 log CFU/g but only 0.68 log CFU/g with smoke. When cooling spanned 15 h, both C. perfringens and S. aureus grew by a total of about 4 log. The addition of liquid smoke inhibited C. perfringens, but S. aureus still achieved a 3.97-log increase. Staphylococcal enterotoxins were detected in five of six samples cooled for 15 h without smoke but in none of the six samples of smoked bellies. In laboratory-scale smoking of whole belly pieces, initial C. perfringens populations of 2.23 ± 0.25 log CFU/g were reduced during smoking to 0.99 ± 0.50 log CFU/g and were 0.65 ± 0.21 log CFU/g after 15 h of cooling. Populations of S. aureus were reduced from 2.00 ± 0.74 to a final concentration of 0.74 ± 0.53 log CFU/g after cooling. Contrary to findings in the ground pork belly system, the 15-h cooling of whole belly pieces did not permit growth of either pathogen. This study demonstrates that if smoked bacon is cooled from 48.9 to 7.2°C (120 to 45°F) within 15 h, a food safety hazard from either C. perfringens or S. aureus is not likely to occur.

Bacterial Growth at Foodservice Operating Temperatures

1981 ◽  
Vol 44 (10) ◽  
pp. 770-775 ◽  
Author(s):  
C. P. RIVITUSO ◽  
O. P. SNYDER
Keyword(s):  
Staphylococcus Aureus ◽  
Clostridium Perfringens ◽  
Bacterial Growth ◽  
Current Literature ◽  
Sensory Quality ◽  
Regression Line ◽  
Generation Times ◽  
The Mean ◽  
Operating Temperatures

A search of current literature was conducted to determine the mean generation times (MGT) at various temperatures for growth of Staphylococcus aureus, Clostridium perfringens, Salmonella and total aerobes in various foods. The data were graphed and a regression line was plotted to begin to form a more definitive time-temperature basis for specification of safe foodservice recipe procedures and to increase sensory quality through control of spoilage organisms. The results show that generation times vary significantly over the range of temperatures normally found in foodservice, and pathogenic bacterial growth slows rapidly below 15–20 C. The results also show that data are quite limited and that there is need for additional studies.

Transfer Volume-Dependent Recovery of Salmonella from Minced Meat

1987 ◽  
Vol 50 (7) ◽  
pp. 584-586 ◽  
Author(s):  
S. KAFEL ◽  
E. POGORZELSKA
Keyword(s):  
Salmonella Typhimurium ◽  
Broth Culture ◽  
Selective Media ◽  
Selective Enrichment ◽  
Salmonella Choleraesuis ◽  
Selective Agar ◽  
Peptone Water ◽  
Pure Cultures ◽  
The Mean ◽  
Minced Meat

Six hundred 25-g samples of ground beef were divided into 3 groups of 200 each and 1 drop of a Salmonella broth culture was added to each sample. After storage at −27°C for 3–4 months, the samples were defrosted and blended with 225 ml of buffered peptone water. Ten ml of each suspension was preenriched at 37°C for 20 h and 10-fold dilutions of the material were made. One ml each of the preenriched culture and dilutions of 10−2, 10−4, 10−6, and 10−8 were transferred to selective enrichment media, and subsequently streaked onto selective agar plates. The mean percentage of Salmonella-positives obtained from all combinations of the selective media in relation to undiluted preenriched material and its 10−2, 10−4, 10−6, and 10−8 dilutions were for Salmonella typhimurium 70, 81, 84, 37, and 2, for Salmonella choleraesuis 64, 78, 66, 30, and 2, and for Salmonella anatum 60, 84, 75, 40, and 1, respectively. Colonies originating from diluted samples, particularly 10−4 and further dilutions, usually represented pure cultures of salmonellae, but from undiluted material were frequently accompanied or outgrown by concomitant bacteria.

Microbiology of Fresh Comminuted Turkey Meat

1976 ◽  
Vol 39 (12) ◽  
pp. 823-829 ◽  
Author(s):  
LINDA S. GUTHERTZ ◽  
JOHN T. FRUIN ◽  
DELANO SPICER ◽  
JAMES L. FOWLER
Keyword(s):  
Staphylococcus Aureus ◽  
San Francisco ◽  
Clostridium Perfringens ◽  
Plate Count ◽  
Most Probable Number ◽  
Probable Number ◽  
Selective Enrichment ◽  
Turkey Meat ◽  
Standard Plate ◽  
The Mean

Standard plate counts, coliform plate and most probable number (MPN) counts, Escherichia coli plate and MPN counts, Staphylococcus aureus MPN counts, and fecal streptococcus counts were determined for 75 samples of fresh ground turkey meat purchased from retail markets in the San Francisco Bay Area. The presence of Clostridium perfringens was determined by both direct plate count and enrichment techniques. Salmonellae were isolated using selective enrichment procedures. Samples were screened for presence of enteroviruses. Aerobic gram-positive and gram-negative organisms were isolated and identified. Clostridium perfringens and Salmonella sp. were isolated from 52% and 28% of the samples, respectively. The mean standard plate count was 84,000,000 per gram. The mean count for E. coli determined by the MPN method was 19 per gram. Fecal streptococci were isolated from 95% of the samples with a mean count of 18,000 per gram. Staphylococcus aureus was isolated from 80% of samples analyzed with a mean count of 34 per gram.

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