Historical Perspectives on Methodology to Detect Listeria monocytogenes

1988 ◽  
Vol 71 (3) ◽  
pp. 644-646 ◽  
Author(s):  
Catherine W Donnelly

Abstract While recognized as a causative agent of illness in animals and humans for some time, the foodborne role of Listeria monocytogenes is a new and emerging one. This review briefly summarizes the historical developments in methodology used to detect the presence of L. monocytogenes. Although clinical procedures exist, these procedures do not consider isolation of Listeria from heavily contaminated environments. Federal agencies such as the U.S. Food and Drug Administration and the U.S. Department of Agriculture have defined protocols for the isolation of Listeria from dairy and meat products, respectively. Each of these protocols, and current problems common to all methods for the isolation of Listeria from food products, are discussed. Finally, future challenges with respect to improvement in our abilities to recognize, isolate, and rapidly identify Listeria in foods are presented

2004 ◽  
Vol 67 (12) ◽  
pp. 2698-2702 ◽  
Author(s):  
STEVEN C. INGHAM ◽  
DENNIS R. BUEGE ◽  
BRENDA K. DROPP ◽  
JILL A. LOSINSKI

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.


2007 ◽  
Vol 70 (12) ◽  
pp. 2749-2756 ◽  
Author(s):  
SARITHA GEDELA ◽  
RACHEL K. GAMBLE ◽  
SUNITA MACWANA ◽  
JOSEPH R. ESCOUBAS ◽  
PETER M. MURIANA

Surface pasteurization was examined in combination with low-phenolic antimicrobial extracts derived from liquid smoke to inhibit and prevent the growth of Listeria monocytogenes during the shelf life of ready-to-eat meats. In preliminary trials with retail frankfurters, one smoke derivative (2-min dip) produced a 0.3-log reduction of L. monocytogenes and a 1-min inbag pasteurization (73.9°C) produced a 2.9-log reduction, whereas a combination of the two treatments produced a 5.3-log reduction that resulted in no detectable Listeria by week 3 under accelerated shelf-life conditions (10°C). In trials with frankfurters manufactured without lactate or diacetate that were treated with a shortened 1-s dip, this smoke extract and one with reduced smoke flavor and color both produced a >4.5-log reduction of L. monocytogenes on frankfurters when heated at 73.9°C for 1 min, with no recoverable Listeria detected for 10 weeks when stored at 6.1°C. When deli turkey breast chubs manufactured without lactate, diacetate, or nitrite were treated with a 1-s dip in combination with radiant-heat pasteurization (270°C), growth of L. monocytogenes was retarded but not prevented. However, in a similar study in which smoke extract treatment of deli turkey breast was combined with in-bag postpackage pasteurization (water submersion at 93.3°C), a 60-, 45-, or even 30-s heat treatment resulted in a 2- to 3-log reduction of L. monocytogenes, with no growth on the meat during 10 weeks of storage at 6.1°C. These findings indicate that reduced-acid low-phenolic antimicrobial liquid smoke derivatives combined with surface pasteurization are capable of reducing or preventing growth of L. monocytogenes to meet the criteria for the U.S. Department of Agriculture Food Safety and Inspection Service Alternative 1 process for ready-to-eat deli meat products manufactured without lactate or diacetate.


1992 ◽  
Vol 55 (7) ◽  
pp. 492-496 ◽  
Author(s):  
I-PING D. HUANG ◽  
AHMED E. YOUSEF ◽  
ELMER H. MARTH ◽  
M. EILEEN MATTHEWS

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.


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 ◽  
...  

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.


1991 ◽  
Vol 54 (1) ◽  
pp. 7-11 ◽  
Author(s):  
JOSEPH LOVETT ◽  
DAVID W. FRANCIS ◽  
JAMES T. PEELER ◽  
ROBERT M. TWEDT

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.


1987 ◽  
Vol 109 (4) ◽  
pp. 363-367
Author(s):  
D. H. Pai

The organizational and technological advances of the last two decades in the U.S. Pressure Vessel and Piping (PVP) Technology are first traced. Highlights of growth in the major organizations supporting PVP technology: ASME Boiler and Pressure Vessel Code, Pressure Vessel Research Committee, and the ASME Pressure Vessels and Piping Division, are given, along with highlights in the technological advances in Design Analysis, Materials and Fabrication. Future challenges in key technological areas for PVP engineers are discussed, including the role of the PVP engineer in developing technologies such as BIOTECHNOLOGY, SUPERCONDUCTIVITY, MICRO-ELECTRONICS, ENERGY, ENVIRONMENTAL ENGINEERING, and ADVANCED MATERIALS. This paper concludes with a discussion of two major institutional challenges of our times: winning public acceptance of technology; competitiveness and foreign trade.


EDIS ◽  
1969 ◽  
Vol 2004 (1) ◽  
Author(s):  
Michael T. Olexa ◽  
Aaron Leviten ◽  
Kelly Samek

This document discusses the important federal laws and regulations that impact solid waste management. Each particular statute is “explained” as it would probably apply to you. It also includes a brief description of the federal agencies responsible for implementing and enforcing these statutes. First and foremost is the Environmental Protection Agency (EPA), but other federal agencies, such as the Department of Agriculture, the U.S. Army Corps of Engineers, and the U.S. Coast Guard, may become involved in the disposal of solid and hazardous wastes. This is EDIS document FE443, a publication of the Department of Food and Resource Economics, Florida Cooperative Extension Service, UF/IFAS, University of Florida, Gainesville, FL. Published December 2003.  https://edis.ifas.ufl.edu/fe443


1990 ◽  
Vol 53 (1) ◽  
pp. 22-25 ◽  
Author(s):  
SUSAN A. McCARTHY ◽  
MILES L. MOTES ◽  
R. MERRILL McPHEARSON

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.


1992 ◽  
Vol 55 (12) ◽  
pp. 952-959 ◽  
Author(s):  
PEGGY S. HAYES ◽  
LEWIS M. GRAVES ◽  
B. SWAMINATHAN ◽  
GLORIA W. AJELLO ◽  
GEORGIA B. MALCOLM ◽  
...  

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).


2005 ◽  
Vol 68 (9) ◽  
pp. 1911-1915 ◽  
Author(s):  
STEVEN C. INGHAM ◽  
REBECCA A. ENGEL ◽  
MELODY A. FANSLAU ◽  
ERICA L. SCHOELLER ◽  
GINA SEARLS ◽  
...  

The U.S. Department of Agriculture has established standards for the composition and shelf stability of various ready-to-eat meat products. These standards may include product pH, moisture:protein ratio, and water activity (aw) values. It is unclear how closely these standards are based on the potential for pathogen growth or toxin production. Because the vacuum packaging used on most ready-to-eat meat products inhibits mold, Staphylococcus aureus is the pathogen most likely to grow on products with reduced aw and increased percentage of water-phase salt. In this study, 34 samples of various ready-to-eat meat products were inoculated with a three-strain mixture of S. aureus, vacuum packaged, and stored at 21°C for 4 weeks. S. aureus numbers decreased by 1.1 to 5.6 log CFU on fermented products (pH ≤ 5.1) with a wide range of salt concentrations and moisture content. Similarly, S. aureus numbers decreased by 3.2 to 4.5 log CFU on dried nonacidified jerky (aw ≤ 0.82; moisture:protein ratio of ≤0.8). Products that were not fermented or dried clearly supported S. aureus growth and cannot be considered shelf stable. The product pH and moisture:protein ratio were the two compositional factors most highly correlated (R2 = 0.84) with S. aureus survival and growth for the types of products tested, but pH and aw or pH and percentage of water-phase salt also may provide useful predictive guidance (R2 = 0.81 and 0.77, respectively).


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