Quantitative Comparison of Two Enrichment Methods for Isolating Listeria monocytogenes from Seafoods

1991 ◽  
Vol 54 (1) ◽  
pp. 7-11 ◽  
Author(s):  
JOSEPH LOVETT ◽  
DAVID W. FRANCIS ◽  
JAMES T. PEELER ◽  
ROBERT M. TWEDT
Keyword(s):  
Listeria Monocytogenes ◽  
Drug Administration ◽  
Clinical Sample ◽  
Quantitative Comparison ◽  
Plate Count ◽  
Department Of Agriculture ◽  
Standard Procedures ◽  
Aerobic Plate Count ◽  
The U.S ◽  
Enrichment Methods

Two enrichment methods that had been used as standard procedures by the U.S. Food and Drug Administration (FDA) and the U.S. Department of Agriculture (USDA) were quantitatively compared for their ability to isolate Listeria monocytogenes from seafoods. Cultures of a clinical sample and a seafood isolate were inoculated into raw and cooked shrimp; cultures heated at 57.8°C for 5 min were added to surimi, cooked crabmeat, and cooked shrimp. With the FDA procedure, which used enrichment intervals of 24 h, 48 h, and 7 d, KOH culture treatment and enrichment for 24 h provided no advantage for Listeria recovery. The FDA procedure isolated heated L. monocytogenes from seafoods at a lower level than the USDA method; however, the two methods isolated unheated cells equally well. The greater selectivity of the USDA procedure may offer an advantage for isolating nonheat-stressed Listeria when the aerobic plate count of the product is high.

Quantitative Comparison of Two Enrichment Methods for Isolating Listeria monocytogenes from Inoculated Ice Cream

1989 ◽  
Vol 52 (12) ◽  
pp. 898-900 ◽  
Author(s):  
ANTHONY D. HITCHINS
Keyword(s):  
Listeria Monocytogenes ◽  
Ice Cream ◽  
Quantitative Comparison ◽  
Portion Size ◽  
Alkali Pretreatment ◽  
Department Of Agriculture ◽  
Test Portion ◽  
Order Of Magnitude ◽  
The U.S ◽  
Enrichment Methods

Two enrichment methods for isolating Listeria monocytogenes (the Lovett method, formerly used by the U.S. Food and Drug Administration, and the revised method for the U. S. Department of Agriculture) were compared using 25 g test portions of spiked vanilla ice cream. Both methods were found to be equally sensitive. Prolonging the enrichments to 7 d and the use of alkali pretreatment had no significant effect on the results. Reduction of the test portion size from 25 to 1 g in the revised USDA method decreased the level of sensitivity by an order of magnitude, as expected.

Contamination Revealed by Indicator Microorganism Levels during Veal Processing

2016 ◽  
Vol 79 (8) ◽  
pp. 1341-1347 ◽  
Author(s):  
JOSEPH M. BOSILEVAC ◽  
RONG WANG ◽  
BRANDON E. LUEDTKE ◽  
TOMMY L. WHEELER ◽  
MOHAMMAD KOOHMARAIE
Keyword(s):  
Escherichia Coli ◽  
Plate Count ◽  
Department Of Agriculture ◽  
E Coli ◽  
Veal Calves ◽  
Indicator Microorganism ◽  
Analysis Of Results ◽  
Aerobic Plate Count ◽  
Inspection Service ◽  
The U.S

ABSTRACT During site visits of veal processors, the U.S. Department of Agriculture, Food Safety Inspection Service (FSIS) has reported processing deficiencies that likely contribute to increased levels of veal contamination. Here, we report the results of measuring aerobic plate count bacteria (APC), Enterobacteriaceae, coliforms (CF), and Escherichia coli during eight sample collections at five veal processors to assess contamination during the harvest of bob veal and formula-fed veal before (n = 5 plants) and after (n = 3 plants) changes to interventions and processing practices. Hides of veal calves at each plant had mean log CFU/100 cm2 APC, Enterobacteriaceae, CF, and E. coli of 6.02 to 8.07, 2.95 to 5.24, 3.28 to 5.83, and 3.08 to 5.59, respectively. Preintervention carcasses had mean log CFU/100 cm2 APC, Enterobacteriaceae, CF, and E. coli of 3.08 to 5.22, 1.16 to 3.47, 0.21 to 3.06, and −0.07 to 3.10, respectively, before and 2.72 to 4.50, 0.99 to 2.76, 0.69 to 2.26, and 0.33 to 2.12, respectively, after changes were made to improve sanitary dressing procedures. Final veal carcasses had mean log CFU/100 cm2 APC, Enterobacteriaceae, CF, and E. coli of 0.36 to 2.84, −0.21 to 1.59, −0.23 to 1.59, and −0.38 to 1.45 before and 0.44 to 2.64, −0.16 to 1.33, −0.42 to 1.20, and −0.48 to 1.09 after changes were made to improve carcass-directed interventions. Whereas the improved dressing procedures resulted in improved carcass cleanliness, the changes to carcass-directed interventions were less successful, and veal processors are urged to use techniques that ensure uniform and consistent delivery of antimicrobials to carcasses. Analysis of results comparing bob veal to formula-fed veal found bob veal hides, preintervention carcasses, and final carcasses to have increased (P < 0.05) APC, Enterobacteriaceae, CF, and E. coli (with the exception of hide Enterobacteriaceae; P > 0.05) relative to formula fed veal. When both veal categories were harvested at the same plant on the same day, similar results were observed. Since identification by FSIS, the control of contamination during veal processing has started to improve, but challenges still persist.

Factors Associated with Salmonella Prevalence on Pork Carcasses in Very Small Abattoirs in Wisconsin

2009 ◽  
Vol 72 (4) ◽  
pp. 714-721 ◽  
Author(s):  
R. J. ALGINO ◽  
G. A. BADTRAM ◽  
B. H. INGHAM ◽  
S. C. INGHAM
Keyword(s):  
Odds Ratio ◽  
Wash Water ◽  
Plate Count ◽  
Processing Conditions ◽  
Department Of Agriculture ◽  
Factors Associated ◽  
Percent Relative Humidity ◽  
Aerobic Plate Count ◽  
Chilled Pork ◽  
The U.S

The U.S. Department of Agriculture has expressed concern over Salmonella prevalence on pork carcasses. Our objectives were to survey the prevalence of Salmonella on pork carcasses in very small Wisconsin abattoirs, and identify processing conditions and indicator bacteria levels associated with reduced Salmonella prevalence. During April to July 2007, sponge samples were obtained from 181 pork carcasses at 10 Wisconsin abattoirs before carcass washing (carcass half A), and after washing and chilling and before fabrication (carcass half B). Each sample was categorized by whether the carcass was skinned, by wash-water temperature (7 to 43°C), and the duration (1 or 2 days), temperature, and percent relative humidity of chilling. Sponge samples were analyzed qualitatively for Salmonella and quantitatively for Escherichia coli, coliforms, Enterobacteriaceae, and aerobic plate count (APC). Salmonella prevalences on skinned and unskinned prewash carcasses were 11.7 and 8.3%, respectively. Corresponding values for chilled carcasses were 32.0 and 19.5% for 1-day chilled carcasses, and 11.4 and 14.7% for 2-day chilled carcasses. Lower Salmonella prevalence on prewash carcasses was significantly related to lower prewash carcass APC levels (odds ratio = 7.8 per change of 1.0 log CFU/cm2), while lower Salmonella prevalence on chilled carcasses was significantly related to 2-day chilling (odds ratio = 5.2), and chilled-carcass levels of coliforms, Enterobacteriaceae, and APC (odds ratio = 1.5 to 1.9 per change of 1.0 log CFU/cm2). Salmonella prevalence on chilled pork carcasses in very small Wisconsin plants could be reduced by chilling carcasses 2 days before fabrication and improving carcass-handling hygiene.

Recovery of Heat-Stressed Listeria monocytogenes from Experimentally and Naturally Contaminated Shrimp

1990 ◽  
Vol 53 (1) ◽  
pp. 22-25 ◽  
Author(s):  
SUSAN A. McCARTHY ◽  
MILES L. MOTES ◽  
R. MERRILL McPHEARSON
Keyword(s):  
Listeria Monocytogenes ◽  
Drug Administration ◽  
Food And Drug Administration ◽  
New Method ◽  
Department Of Agriculture ◽  
The U.S ◽  
Thermally Stressed

A method was developed to enhance recovery of thermally stressed Listeria monocytogenes from internally contaminated shrimp. Shrimp tail meat was inoculated with 105 L. monocytogenes cells/g and boiled for 1–5 min. Thermally stressed L. monocytogenes cells were recovered following cold enrichment for 3 d without broth. Methods of the Food and Drug Administration and the U.S. Department of Agriculture for isolating L. monocytogenes permitted recovery of the organism from shrimp boiled for 1 min: however, with the new method, L. monocytogenes cells were recovered from shrimp boiled up to 5 min. No Listeria spp. were recovered from naturally contaminated, frozen, imported shrimp after 1 min of boiling.

Comparison of Three Selective Enrichment Methods for the Isolation of Listeria monocytogenes from Naturally Contaminated Foods

1992 ◽  
Vol 55 (12) ◽  
pp. 952-959 ◽  
Author(s):  
PEGGY S. HAYES ◽  
LEWIS M. GRAVES ◽  
B. SWAMINATHAN ◽  
GLORIA W. AJELLO ◽  
GEORGIA B. MALCOLM ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
The Netherlands ◽  
Department Of Agriculture ◽  
Selective Enrichment ◽  
Negative Results ◽  
Sporadic Cases ◽  
Inspection Service ◽  
The U.S ◽  
Enrichment Methods ◽  
Better Than

Three selective enrichment procedures—the U.S. Food and Drug Administration (FDA) method, the U.S. Department of Agriculture (USDA) method, and the Netherlands Government Food Inspection Service (NGFIS) method—were compared for isolating Listeria monocytogenes from contaminated foods. The foods were obtained from the refrigerators of patients with culture-proven listeriosis who were identified through multistate active surveillance in a U.S. population of 19 million. The study was designed to identify foods that may be important in transmission of L. monocytogenes in sporadic cases of human listeriosis. Of 899 foods analyzed by all three methods, 121 were positive for L. monocytogenes by at least one method. The three enrichment methods detected L. monocytogenes in 65% (FDA), 74% (USDA), and 74% (NGFIS) of the foods shown to contain L. monocytogenes. The differences among the three methods were not statistically significant. However, the recovery of L. monocytogenes by a combination of any two methods (USDA-FDA 88%, USDA-NGFIS 91%, FDA-NGFIS 87%) was significantly better than that by one method alone (p < 0.02). The differences among the combinations of methods were not statistically significant. These results suggest that at least two enrichment methods must be used in combination to recover L. monocytogenes from contaminated foods with a success rate near 90%. Correlations were observed between negative results and low (<0.3 CFU/g) level of L. monocytogenes contamination for the USDA (p << 0.001) and NGFIS (p << 0.001) methods. A similar but somewhat weaker association was observed for the FDA method (p < 0.06).

Thermal Inactivation of Listeria monocytogenes in Chicken Gravy

1992 ◽  
Vol 55 (7) ◽  
pp. 492-496 ◽  
Author(s):  
I-PING D. HUANG ◽  
AHMED E. YOUSEF ◽  
ELMER H. MARTH ◽  
M. EILEEN MATTHEWS
Keyword(s):  
Heat Treatment ◽  
Listeria Monocytogenes ◽  
Heat Resistance ◽  
Thermal Inactivation ◽  
Refrigerated Storage ◽  
Department Of Agriculture ◽  
Large Numbers ◽  
Z Value ◽  
D Values ◽  
The U.S

Heat resistance of Listeria monocytogenes strains V7 and Scott A in chicken gravy and changes in heat resistance during refrigerated storage were studied. After chicken gravy was made, it was cooled to 40°C, inoculated with 105 CFU L. monocytogenes per ml of gravy, and then stored at 7°C for 10 d. Gravy was heated at 50, 55, 60, and 65°C immediately after inoculation and after 1, 3, 5, and 10 d of refrigerated storage. The D values for strains Scott A and V7 in gravy heated at 50°C at day 0 were 119 and 195 min and at day 10 they were 115 and 119 min, respectively, whereas at 65°C comparable values at day 0 were 0.48 and 0.19 min and at day 10 they were 0.014 and 0.007 min. Heat resistance (expressed as D values) was greater at day 0 than at the end of refrigerated storage. The z values ranged from 3.41 to 6.10°C and were highest at the early stages of chill storage and then decreased at the later stages. Strain V7 was more heat resistant than Scott A at 50°C. Strain Scott A always had a higher z value than did strain V7 at the same storage interval. A heat treatment greater than the 4-D process recommended by the U.S. Department of Agriculture was required to inactivate the large numbers of L. monocytogenes that developed in chicken gravy during refrigerated storage.

Prevalence, Types, and Geographical Distribution of Listeria monocytogenes from a Survey of Retail Queso Fresco and Associated Cheese Processing Plants and Dairy Farms in Sonora, Mexico†

2007 ◽  
Vol 70 (11) ◽  
pp. 2596-2601 ◽  
Author(s):  
R. I. MORENO-ENRIQUEZ ◽  
A. GARCIA-GALAZ ◽  
E. ACEDO-FELIX ◽  
H. GONZALEZ-RIOS ◽  
J. E. CALL ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Environmental Samples ◽  
Northern Region ◽  
Pulsed Field Gel Electrophoresis ◽  
Department Of Agriculture ◽  
Retail Markets ◽  
Processing Plants ◽  
Contact Surfaces ◽  
Inspection Service ◽  
The U.S

In the first part of this study, samples were collected from farms, cheese processing plants (CPPs), and retail markets located in various geographical areas of Sonora, Mexico, over a 12-month period during the summer of 2004 and winter of 2005. Four (all Queso Fresco [QF] from retail markets) of 349 total samples tested positive for Listeria monocytogenes (Lm). Of these four positive samples, three were collected in the northern region and one in the southern region of Sonora. Additionally, two were collected during the winter months, and two were collected during the summer months. For the second part of the study, a total of 39 samples from a farm, a CPP, and retail markets were collected and processed according to a combination of the Norma Oficial Mexicana NOM-143-SSA1-1995.10 method (NOM) and the U.S. Food and Drug Administration (FDA) Bacteriological Analytical Manual method, and 27 samples from these same locations were collected and processed according to the U.S. Department of Agriculture Food Safety and Inspection Service method (USDA-FSIS). The NOM-FDA method recovered the pathogen from 6 (15%) of 39 samples (one cheese and five product contact surfaces), while the USDA-FSIS method recovered the pathogen from 5 (18.5%) of 27 samples (all product contact surfaces). In addition, the 40 isolates recovered from the 15 total samples that tested positive for Lm grouped into five distinct pulsotypes that were ca. 60% related, as determined by pulsed-field gel electrophoresis analysis. The results of this study confirmed a 3.4% prevalence of Lm in QF collected from retail markets located in Sonora and no appreciable difference in the effectiveness of either the NOM-FDA or USDA-FSIS method to recover the pathogen from cheese or environmental samples.

scholarly journals Survival of Listeria monocytogenes during Storage of Ready-to-Eat Meat Products Processed by Drying, Fermentation, and/or Smoking

2004 ◽  
Vol 67 (12) ◽  
pp. 2698-2702 ◽  
Author(s):  
STEVEN C. INGHAM ◽  
DENNIS R. BUEGE ◽  
BRENDA K. DROPP ◽  
JILL A. LOSINSKI
Keyword(s):  
Listeria Monocytogenes ◽  
Water Activity ◽  
Room Temperature ◽  
Meat Products ◽  
Department Of Agriculture ◽  
Poultry Products ◽  
Beef Jerky ◽  
The U.S

The survival of Listeria monocytogenes was evaluated on 15 ready-to-eat meat products made using drying, fermentation, and/or smoking. The products were obtained from six processors and included summer sausage, smoked cured beef, beef jerky, snack stick, and pork rind and crackling products. The water activity of the products ranged from 0.27 (pork rinds and cracklings) to 0.98 (smoked cured beef slices). Products were inoculated with a five-strain cocktail of L. monocytogenes, repackaged under either vacuum or air, and then stored either at room temperature (21°C) or under refrigeration (5°C) for 4 to 11 weeks. Numbers of L. monocytogenes fell for all products during storage, ranging from a decrease of 0.8 log CFU on smoked cured beef slices during 11 weeks under vacuum at 5°C to a decrease of 3.3 log CFU on a pork rind product stored 5 weeks under air at 21°C. All of the products tested could be produced under alternative 2 of the U.S. Department of Agriculture regulations mandating control of L. monocytogenes on ready-to-eat meat and poultry products. For many of the products, 1 week of postprocessing storage prior to shipment would act as an effective postlethality treatment and would allow processors to operate under alternative 1 of these regulations.

Microbiological Quality of Shawarma in Saudi Arabia

1985 ◽  
Vol 48 (9) ◽  
pp. 811-814 ◽  
Author(s):  
M. AYAZ ◽  
F. A. OTHMAN ◽  
T. O. BAHARETH ◽  
A. M. AL-SOGAIR ◽  
W. N. SAWAYA
Keyword(s):  
Saudi Arabia ◽  
Foodborne Pathogens ◽  
Fast Food ◽  
Health Hazard ◽  
Microbiological Quality ◽  
Plate Count ◽  
Standard Procedures ◽  
Fast Food Restaurants ◽  
Aerobic Plate Count ◽  
Meat Samples

A total of 108 shawarma (cooked meat) samples were aseptically collected from various fast-food restaurants in Riyadh, Saudi Arabia. These samples were examined by standard procedures for determination of aerobic plate count (APC), and counts of coliforms, Staphylococcus aureus, Clostridium perfringens, and the detection of salmonellae. The APC ranged from 102 to 3.0 × 108 CFU/g. The counts for coliforms, S. aureus and C. perfringens ranged from <10 to 106, <10 to 105 and <10 to 106 CFU/g, respectively. Twelve percent of the shawarma samples was positive for Salmonella. The results of this investigation indicate that foodborne pathogens present in shawarmas constitute a potential public health hazard.

Histamine-Related Hygienic Qualities and Bacteria Found in Popular Commercial Scombroid Fish Fillets in Taiwan

2004 ◽  
Vol 67 (2) ◽  
pp. 407-412 ◽  
Author(s):  
YUNG-HSIANG TSAI ◽  
HSIEN-FENG KUNG ◽  
TSONG-MING LEE ◽  
GUO-TAI LIN ◽  
DENG-FWU HWANG
Keyword(s):  
Escherichia Coli ◽  
Selective Medium ◽  
Plate Count ◽  
Average Content ◽  
Bacterial Strains ◽  
Allowable Limit ◽  
Fish Fillets ◽  
Southern Taiwan ◽  
Aerobic Plate Count ◽  
The U.S

To determine the histamine-relatedhygienic qualities and bacteria of scombroid fish fillets sold in traditionalretail markets, 61 samples were collected from northern and southern Taiwan. It was found that the content of volatile base nitrogen in most samples was below 25 mg/100 g, which is the regulatory level in Taiwan. The ratio of unacceptable samples/total samples for aerobic plate count and Escherichia coli was 100% and 15% in northern samples and 100% and 20% in southern samples, respectively, compared with the requirements of hygienic standards. The average content of various biogenic amines in all samples were lower than 3 mg/100 g, except for histamine average content (4.6 mg/100 g) in southern samples. Among southern samples, four samples contained 12.8 to 28.8 mg/100 g histamine, which is more than 5 mg/100 g that is the allowable limit suggested by the U.S. Food and Drug Administration. Furthermore, 14 bacterial strains were isolated from sailfish fillets on a selective medium for histamine-forming bacteria. These presumptive histamine-forming strains, such as Proteus, Enterobacter, Klebsiella, Rahnella, and Acinetobacter, have been identified and found to produce 20 to 2,000 ppm histamine after incubating at 37°C for 24 h.

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