Viability of Listeria monocytogenes Strain Brie-1 in the Avian Egg

1990 ◽  
Vol 53 (1) ◽  
pp. 15-21 ◽  
Author(s):  
PAMELA J. SIONKOWSKI ◽  
LEORA A. SHELEF
Keyword(s):  
Listeria Monocytogenes ◽  
Sharp Decline ◽  
Cell Numbers ◽  
Generation Times ◽  
Heat Treated ◽  
Egg Yolks ◽  
Survival And Growth ◽  
Avian Egg

The viability of Listeria monocytogenes strain Brie-1 was studied in raw and heat-treated (121°C, 15 min) whole eggs, albumen, or yolks during storage at 5 and 20°C. Studies with raw eggs showed that the organism grew only in egg yolks, where initial numbers (106 cells/g) increased to 108 cells/g (generation times of 1.7 d and 2.4 h at 5 and 20°C, respectively). Cell numbers in whole eggs initially declined and then leveled off. A sharp decline in cell numbers was observed in the raw albumen (to 102 cells/g after 22 d at 5°C and to <10 after 55 h at 20°C). In contrast, the organism grew in all heat-treated egg samples. Generation times for cooked whole eggs, yolks, and albumen were 1.9, 2.3, and 2.4 d at 5°C, and 2.6, 2.6, and 3.5 h at 20°C, respectively. The rapid initial decline in populations was observed in raw albumen (pH 8.9), and after adjustments to pH 7.0 or 8.0. Numbers of surviving cells/g after 35 d at 5°C were reduced to 104, 103, and <10, at pH 7, 8, and 9 respectively. With the exception of the raw albumen, refrigerated raw and cooked eggs supported survival and growth of L. monocytogenes, and hence can serve as vehicle of transmission of listeriosis.

Fate of Listeria monocytogenes in Bovine Manure–Amended Soil

2004 ◽  
Vol 67 (8) ◽  
pp. 1676-1681 ◽  
Author(s):  
XIUPING JIANG ◽  
MAHBUB ISLAM ◽  
JENNIE MORGAN ◽  
MICHAEL P. DOYLE
Keyword(s):  
Listeria Monocytogenes ◽  
Environmental Conditions ◽  
Fresh Produce ◽  
Soil Microflora ◽  
Soil Samples ◽  
Cell Numbers ◽  
Survival And Growth ◽  
Field Workers ◽  
Amended Soil

The survival and growth of Listeria monocytogenes in soil amended with bovine manure was studied under different environmental conditions of temperature, nutrients, and soil microflora. Autoclaved soil was compared with unautoclaved soil for assessing the influence of competitive soil microflora on the survival of L. monocytogenes. Initial L. monocytogenes cell numbers of 5 to 6 log CFU/g survived for up to 43, 43, and 14 days in manure-amended autoclaved soil at 5, 15, and 21°C, respectively. In manure-amended unautoclaved soil, the pathogen was detectable for up to 43, 21, and 21 days at 5, 15, and 21°C, respectively. L. monocytogenes was inactivated more rapidly in autoclaved soil amended with manure at a manure/soil ratio of 1:10 than in the more dilute (1:100) manure in soil samples at both 15 and 21°C. However, in manure-amended unautoclaved soil, L. monocytogenes survived longer in samples with ratios of 1:10 than in the more dilute (1:100) manure-amended soil. The persistence of L. monocytogenes for several weeks in manure-amended soil suggests listeriae could be transmitted through soil to fresh produce or to shoes, clothing, and hands of field workers, especially during the cold months.

Behaviour ofStreptococcus lactisin heat treated (80 °C for 30 min) or sterilized cow's and ewe's milk

1983 ◽  
Vol 50 (3) ◽  
pp. 357-363 ◽  
Author(s):  
Francisco J. Chavarri ◽  
Jose A. Nuñez ◽  
Manuel Nuñez
Keyword(s):  
Acid Production ◽  
Generation Time ◽  
Buffer Capacity ◽  
Cow’S Milk ◽  
Cow's Milk ◽  
Vitamin Content ◽  
Streptococcus Lactis ◽  
Generation Times ◽  
Heat Treated ◽  
Ewe's Milk

SummaryGeneration times and acid production after 6 and 24 h by 20 strains ofStreptococcus lactisof dairy origin were determined in heat treated (80 °C for 30 min) and sterilized cow's and ewe's milk. Ewe's milk enhanced growth of the streptococci, with significantly (P< 0·001) shorter generation times and higher acid production after 6 h incubation than cow's milk, probably due to its higher vitamin content. The stronger buffer capacity of ewe's milk allowed a higher (P< 0·001) acid production after 24 h than cow's milk. A stimulatory effect of sterilization on generation time and acid production after 24 h was observed in cow's milk. However, the heat treated ewe's milk was shown to be a better substrate than sterilized ewe's milk forStr. lactis.

scholarly journals A simplified method for extracting androgens from avian egg yolks

Zoo Biology ◽  
2009 ◽  
Vol 28 (2) ◽  
pp. 137-143 ◽  
Author(s):  
Corinne P. Kozlowski ◽  
Joan E. Bauman ◽  
D. Caldwell Hahn
Keyword(s):  
Simplified Method ◽  
Egg Yolks ◽  
Avian Egg

Control of Listeria monocytogenes with Combined Antimicrobials after Postprocess Contamination and Extended Storage of Frankfurters at 4° C in Vacuum Packages

2002 ◽  
Vol 65 (2) ◽  
pp. 299-307 ◽  
Author(s):  
JOHN SAMELIS ◽  
GERARD K. BEDIE ◽  
JOHN N. SOFOS ◽  
KEITH E. BELK ◽  
JOHN A. SCANGA ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Sodium Acetate ◽  
Sensory Quality ◽  
Sodium Lactate ◽  
Hot Water ◽  
Processed Meat ◽  
C Storage ◽  
Heat Treated ◽  
Cured Meat ◽  
Sodium Diacetate

Contamination of ready-to-eat foods, such as frankfurters, with Listeria monocytogenes, is a major concern that needs to be addressed in order to enhance the safety of these products. The objective of this study was to determine the effectiveness of combinations of antimicrobials included in the formulation of frankfurters against L. monocytogenes inoculated (103 to 104 CFU/cm2) on their surface after peeling and before vacuum packaging. In addition, the antilisterial effect of immersing the packaged products, prepared with or without antimicrobials, in hot (75 or 80°C) water for 30 to 90 s was evaluated. Samples were stored at 4°C for up to 120 days and periodically analyzed for pH and for microbial growth on tryptic soy agar plus 0.6% yeast extract (TSAYE) and PALCAM agar. Sodium lactate (1.8%; 3% of a 60% commercial solution) used alone inhibited growth of L. monocytogenes for 35 to 50 days, whereas when used in combination with 0.25% sodium acetate, sodium diacetate, or glucono-δ-lactone (GDL), sodium lactate inhibited growth throughout storage (120 days). Immersing packaged frankfurters in hot water (80°C, 60 s) reduced inoculated populations of L. monocytogenes by 0.4 to 0.9 log CFU/cm2 and reduced its growth by 1.1 to 1.4 log CFU/cm2 at 50 to 70 days of storage in samples containing 1.8% sodium lactate alone. However, immersion of frankfurters containing no antimicrobials in hot water (75 or 80°C) did not inhibit growth of the pathogen for more than 10 to 20 days, unless one frankfurter was placed per bag and heat treated for 90 s. These results indicate that the inclusion of 1.8% sodium lactate with 0.25% sodium acetate, sodium diacetate, or GDL in cured meat formulations may control L. monocytogenes growth during refrigerated (4°C) storage. Additional studies are required to evaluate the effects of these combinations at abusive temperatures of storage, as well as on additional processed meat formulations and on the sensory quality and shelf life of products.

Survival and Growth of Listeria monocytogenes on Fresh-Cut “Athena” and “Rocky Ford” Cantaloupes During Storage at 4°C and 10°C

2016 ◽  
Vol 13 (11) ◽  
pp. 587-591 ◽  
Author(s):  
Esmond Nyarko ◽  
Kalmia E. Kniel ◽  
Russell Reynnells ◽  
Cheryl East ◽  
Eric T. Handy ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Survival And Growth ◽  
Fresh Cut

Behavior of Listeria monocytogenes at 4 and 22°C in Whey and Skim Milk Containing 6 or 12% Sodium Chloride

1989 ◽  
Vol 52 (9) ◽  
pp. 625-630 ◽  
Author(s):  
DEMETRIOS K. PAPAGEORGIOU ◽  
ELMER H. MARTH
Keyword(s):  
Listeria Monocytogenes ◽  
Sodium Chloride ◽  
Skim Milk ◽  
Salt Tolerant ◽  
Ph Values ◽  
Generation Times ◽  
Order Of Magnitude ◽  
Entire Experiment

Autoclaved samples of skim milk and deproteinated whey were fortified with 6 or 12% NaCl, inoculated with Listeria monocytogenes strains Scott A or California (CA), to contain ca. 1.0 × 103 cfu/ml (in the products with 6% salt) or ca. 5.0 × 103 cfu/ml (in the products with 12% salt) and incubated at 4 and 22°C. The pH values of the 6% salted whey, 6% salted skim milk, 12% salted whey, and 12% salted skim milk were 5.65, 6.20, 5.50, and 6.00 respectively. These values remained relatively constant during the entire experiment. Listeria counts were obtained by surface-plating appropriate dilutions and/or undiluted samples on Trypticase Agar (TA). Samples in which L. monocytogenes was not detected, were re-examined after 2, 4, 6 and 8 weeks of cold-enrichment. Generation times of L. monocytogenes in 6% salted whey at 22°C (3.67 h and 3.56 h for strains Scott A and CA, respectively) were significantly shorter than those in 6% salted skim milk at 22°C (4.31 and 4.42 h for the two strains, respectively). Generation times in 6% salted products at 4°C ranged between 37.49 h and 49.43 h. Maximum populations reached at 22 and 4°C ranged from 7.58 to 8.10 Log10 cfu/ml, and were significantly higher in 6% salted whey than in 6% salted skim milk. In 12% salted whey and skim milk incubated at 22°C, L. monocytogenes gradually decreased in numbers. Strain CA was inactivated within 85 d in 12% salted skim milk or within 110 d in 12% salted whey, and was significantly less salt tolerant than strain Scott A which survived for more than 130 d under the same conditions. Loss of viability by both strains was similar in 12% salted whey and skim milk after 130 d of storage at 4°C, and the decreases in population were less than 0.7 order of magnitude.

A Solid Agar Overlay Method for Recovery of Heat-Injured Listeria monocytogenes

2006 ◽  
Vol 69 (2) ◽  
pp. 428-431 ◽  
Author(s):  
ZHINONG YAN ◽  
JOSHUA B. GURTLER ◽  
JEFFREY L. KORNACKI
Keyword(s):  
Listeria Monocytogenes ◽  
Yeast Extract ◽  
Foodborne Pathogens ◽  
Bacterial Cells ◽  
Heat Injury ◽  
Layer Method ◽  
Heat Treated ◽  
Solid Agar ◽  
Overlay Method ◽  
Agar Layer

A solid agar overlay method was developed for recovery of heat-injured Listeria monocytogenes. Presolidified nonselective tryptic soy agar with 0.6% yeast extract (TSAYE, 2% agar) was overlaid on top of solidified modified Oxford agar (MOX). Heat injury of L. monocytogenes was conducted at 58°C for 6 min in a jacketed flask filled with tryptic soy broth. Both noninjured and heat-treated L. monocytogenes cells were plated onto TSAYE, MOX, and TSAYE-MOX plates. No significant differences (P &gt; 0.05) in recovery were found among the three media for noninjured bacterial cells. Recovery of heat-injured L. monocytogenes cells on TSAYE-MOX overlay plates was equivalent to that on the nonselective TSAYE medium, whereas recovery on the selective MOX medium was significantly lower (P &lt; 0.05) compared with both TSAYE and the overlay plates. There were no significant differences (P &gt; 0.05) among the overlay plates prepared 0, 2, 4, 6, 8, 16, and 24 h prior to plating heat-injured bacterial cells. The TSAYE-MOX overlay also allowed differentiation of L. monocytogenes from a mixture of four other types of foodborne pathogens. This solid agar overlay method for recovery of heat-injured L. monocytogenes cells is less time-consuming and less complicated than the conventional overlay-underlay technique and the double overlay modification of the thin agar layer method and may allow for greater laboratory plating efficiencies.

Contamination of Beef Tissue Surfaces by Cattle Manure Inoculated with Salmonella typhimurium and Listeria monocytogenes

1991 ◽  
Vol 54 (2) ◽  
pp. 102-104 ◽  
Author(s):  
JAMES S. DICKSON ◽  
MICHAEL D. MACNEIL
Keyword(s):  
Listeria Monocytogenes ◽  
Salmonella Typhimurium ◽  
Phosphate Buffer ◽  
Bacterial Species ◽  
Cattle Manure ◽  
Tissue Type ◽  
Fat Tissue ◽  
Cell Numbers ◽  
Tissue Surfaces

Contamination of beef lean and fat tissue surfaces by Salmonella typhimurium and Listeria monocytogenes was evaluated using phosphate buffer or sterilized manure as an inoculation menstruum. Immersion in inoculated phosphate buffer resulted in an increase in numbers of attached cells during the 120 min inoculation for both bacterial species. Tissue immersed in inoculated manure generally showed an increase in cell numbers up to 10 min of immersion with only slight increases in cell numbers from 10 to 120 min. Fewer cells attached to either tissue type from the manure inoculum (P&lt;0.05), although actual numerical differences were small.

Incidence and Survival of Listeria monocytogenes in Ready-To-Eat Seafood Products

1997 ◽  
Vol 60 (4) ◽  
pp. 372-376 ◽  
Author(s):  
SUSAN A. MCCARTHY
Keyword(s):  
Listeria Monocytogenes ◽  
Storage Time ◽  
Storage Temperature ◽  
Storage Conditions ◽  
Plate Count ◽  
Standard Plate Count ◽  
Smoked Salmon ◽  
Standard Plate ◽  
Seafood Products ◽  
Survival And Growth

The effects of processing and postprocess storage conditions on the incidence and survival of Listeria monocytogenes on crawfish (Procambaris sp.), crabmeat (Callinectus sapidus), and smoked salmon (Salmo salar) were evaluated. L. monocytogenes was recovered from 3% of whole boiled market crawfish samples and 17% of frozen vacuum-packaged partially cooked crawfish tail meat, but not from boiled crabmeat or smoked salmon. Contamination was most likely due to postprocess handling as commonly used methods of cooking (5 min boil or 20 min steep) reduced L. monocytogenes to nondetectable levels in laboratory-contaminated crawfish. In postprocess storage temperature abuse studies, cooked whole crawfish were inoculated internally and externally with 3.0 log CFU of L. monocytogenes per g and incubated at 22 or 30°C for 6 h. The greatest increase in numbers of cells, 1.9 log CFU/g (determined by standard plate count), occurred at 30°C on externally contaminated crawfish. There was little change in numbers of L. monocytogenes during cold storage (6°C, 5 days; −20°C, 15 days). There was little change in cell numbers associated with products stored at 22 or −20°C. At 6°C, numbers of cells associated with crabmeat increased by 3.8 log MPN/g after 6 days; however, there was no increase in numbers of cells associated with salmon. The results show that the survival and growth characteristics of L. monocytogenes are dependent on storage time and temperature and the nature of the seafood product.

Effect of Single or Sequential Hot Water and Lactic Acid Decontamination Treatments on the Survival and Growth of Listeria monocytogenes and Spoilage Microflora during Aerobic Storage of Fresh Beef at 4, 10, and 25°C

2004 ◽  
Vol 67 (12) ◽  
pp. 2703-2711 ◽  
Author(s):  
KONSTANTINOS P. KOUTSOUMANIS ◽  
LAURA V. ASHTON ◽  
IFIGENIA GEORNARAS ◽  
KEITH E. BELK ◽  
JOHN A. SCANGA ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Lactic Acid Bacteria ◽  
Hot Water ◽  
Microbial Profile ◽  
Spoilage Bacteria ◽  
Brochothrix Thermosphacta ◽  
Survival And Growth ◽  
Spoilage Microflora ◽  
Storage Temperatures

The survival and growth of Listeria monocytogenes and spoilage microflora during storage of fresh beef subjected to different decontamination treatments was studied. Fresh beef inoculated with a five-strain mixture of L. monocytogenes (5.18 log CFU/cm2) was left untreated (control) or was immersed (30 s) in hot water (HW; 75°C), 2% lactic acid (LA; 55°C), hot water followed by lactic acid (HW-LA), or lactic acid followed by hot water (LA-HW) and then stored aerobically at 4, 10, and 25°C for 25, 17, and 5 days, respectively. Initial populations of L. monocytogenes were reduced by 0.82 (HW), 1.43 (LA), 2.73 (HW-LA), and 2.68 (LA-HW) log CFU/cm2. During storage, the pathogen grew at higher rates in HW than in control samples at all storage temperatures. Acid decontamination treatments (LA, HW-LA, and LA-HW) resulted in a weaker inhibition of L. monocytogenes (P &lt; 0.05) at 25°C than at 4 and 10°C. In general, the order of effectiveness of treatments was HW-LA &gt; LA &gt; LA-HW &gt; HW &gt; control at all storage temperatures tested. In untreated samples, the spoilage microflora was dominated by pseudomonads, while lactic acid bacteria, Enterobacteriaceae, and yeasts remained at lower concentrations during storage. Brochothrix thermosphacta was detected periodically in only a limited number of samples. Although decontamination with HW did not affect the above spoilage microbial profile, acid treatments shifted the predominant microflora in the direction of yeasts and gram-positive bacteria (lactic acid bacteria). Overall, the results of the present study indicate that decontamination with LA and combinations of LA and HW could limit growth of L. monocytogenes and inhibit pseudomonads, which are the main spoilage bacteria of fresh beef stored under aerobic conditions. However, to optimize the efficacy of such treatments, they must be applied in the appropriate sequence and followed by effective temperature control.

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