Heterogeneity in single-cell outgrowth of Listeria monocytogenes in half Fraser enrichment broth is affected by strain variability and physiological state

ABSTRACT The impacts of 12 common food industry stresses on the single-cell growth probability and single-cell lag time distribution of Listeria monocytogenes were determined in half Fraser broth, the primary enrichment broth of the International Organization for Standardization detection method. First, it was determined that the ability of a cell to multiply in half Fraser broth is conditioned by its history (the probability for a cell to multiply can be decreased to 0.05), meaning that, depending on the stress in question, the risk of false-negative samples can be very high. Second, it was established that when cells are injured, the single-cell lag times increase in mean and in variability and that this increase represents a true risk of not reaching the detection threshold of the method in the enrichment broth. No relationship was observed between the impact on single-cell lag times and that on growth probabilities. These results emphasize the importance of taking into account the physiological state of the cells when evaluating the performance of methods to detect pathogens in food.

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Antimicrobial Effects of d-3-Phenyllactic Acid on Listeria monocytogenes in TSB-YE Medium, Milk, and Cheese

Journal of Food Protection ◽

10.4315/0362-028x-61.10.1281 ◽

1998 ◽

Vol 61 (10) ◽

pp. 1281-1285 ◽

Cited By ~ 42

Author(s):

VIRGINIE DIEULEVEUX ◽

MICHELINE GUÉGUEN

Keyword(s):

Listeria Monocytogenes ◽

Growth Phase ◽

Physiological State ◽

Geotrichum Candidum ◽

Bactericidal Effect ◽

Exponential Growth Phase ◽

Bacteriostatic Effect ◽

Experimental Conditions ◽

Phenyllactic Acid ◽

Whole Milk

d-3-Phenyllactic acid is a compound with anti-Listeria activity which is produced and secreted by the yeastlike fungus, Geotrichum candidum. This compound has a bactericidal effect independent of the physiological State of Listeria monocytogenes when added at a concentration of 7 mg/ml to tryptic soy broth supplemented with yeast extract (TSB-YE). An initial L. monocytogenes population of 105 CFU/ml was reduced 100-fold (2 log) after 4 days of culture at 25 °C in TSB-YE containing d-3-phenyllactic acid. The Listeria population was reduced 1,000-fold (3 log) when the compound was added during the exponential growth phase, and was reduced to less than 10 CFU/ml when it was added during the stationary phase. d-3-Phenyllactic acid had a bacteriostatic effect in UHT whole milk, reducing the population by 4.5 log, to give fewer cells than in the control after 5 days of culture. The results obtained with L. monocytogenes at concentrations of 105 and 103 CFU/ml in cheese curds were less conclusive. d-3-Phenyllactic acid was 10 times less active than nisin in our experimental conditions (TSB-YE at 25°C).

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Variability in lag duration of Listeria monocytogenes strains in half Fraser enrichment broth after stress affects the detection efficacy using the ISO 11290-1 method

International Journal of Food Microbiology ◽

10.1016/j.ijfoodmicro.2020.108914 ◽

2021 ◽

Vol 337 ◽

pp. 108914

Author(s):

Jasper W. Bannenberg ◽

Tjakko Abee ◽

Marcel H. Zwietering ◽

Heidy M.W. den Besten

Keyword(s):

Listeria Monocytogenes ◽

Enrichment Broth

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Effect of Enrichment Media and Sampling Protocol on Recovery of Listeria monocytogenes

Journal of Food Protection ◽

10.4315/0362-028x-53.6.505 ◽

1990 ◽

Vol 53 (6) ◽

pp. 505-507 ◽

Cited By ~ 6

Author(s):

J. S. BAILEY ◽

D. L. FLETCHER ◽

N. A. COX

Keyword(s):

Listeria Monocytogenes ◽

Pure Culture ◽

Sampling Protocol ◽

Enrichment Broth ◽

Secondary Enrichment ◽

Pure Cultures ◽

University Of Vermont

These studies examined the differences in recovery of Listeria monocytogenes from pure culture and in the populations of mixed aerobic microflora from chicken and Brie cheese incubated in University of Vermont (UVM) and Listeria enrichment broth (LEB) enrichment broths for different times and conditions. No significant differences were observed in levels of L. monocytogenes from pure cultures in UVM or LEB on any sampling day. No differences were observed in the levels of mixed microflora from Brie cheese in either UVM or LEB, but from chicken rinse the level of mixed flora competitors was significantly higher on all sampling days in LEB as compared to UVM. No differences were observed between a single enrichment in UVM or LEB for 2 d and a transfer to a secondary enrichment tube after 1 d. Overall, the level of mixed microflora capable of growing in enrichment broths was greater from chicken rinse than from Brie cheese. The ratio of L. monocytogenes to mixed microflora which survived the selective enrichments was most favorable for recovery of L. monocytogenes after 2 d of enrichment.

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Changes in Heat Resistance Resulting from pH and Nutritional Shifts of Acid-Adapted and Non–Acid-Adapted Listeria monocytogenes Scott A†

Journal of Food Protection ◽

10.4315/0362-028x-67.2.316 ◽

2004 ◽

Vol 67 (2) ◽

pp. 316-321 ◽

Cited By ~ 8

Author(s):

DARRELL O. BAYLES

Keyword(s):

Listeria Monocytogenes ◽

Heat Resistance ◽

Frequency Distribution ◽

Culture Supernatant ◽

Physiological State ◽

Distribution Data ◽

Treatment Conditions ◽

Lower Heat ◽

Full Factorial ◽

Cell Free Culture Supernatant

Stationary-phase Listeria monocytogenes cells that were either pH dependent acid adapted or not acid adapted were heat challenged at 60°C in a two-level full factorial design for three variables. The three variables and the levels consisted of tryptic soy broth (TSB) and sterile cell-free culture supernatant (sterile TSB), the presence and absence of 1% added glucose, and pH 4.8 and pH 7. Non–acid-adapted cells were most heat resistant when challenged in TSB (mean decimal reduction times at 60°C: D60 = 1.16 min). In the absence of added glucose, non–acid-adapted cells had similar D60-values for inactivations at pH 4.8 and pH 7; however, the presence of glucose caused non–acid-adapted cells challenged at pH 4.8 to be more heat sensitive (D60 = 0.65 min) than those inactivated at pH 7 (D60 = 1.03 min), indicating an interaction between glucose and pH. Overall, the significantly decreased heat resistance of the acid-adapted cells was due to the presence of glucose (D60 = 0.78 min without glucose, D60 = 0.59 min with glucose). Acid-adapted cells heat challenged in TSB had similar D60-values for inactivations at pH 4.8 and pH 7; however, acid-adapted cells in sterile TSB challenged at pH 4.8 (D60 = 0.52 min) had significantly lower heat resistance than did cells challenged at pH 7 (D60 = 0.76 min), indicating an interaction between the medium and pH. The L. monocytogenes survivor data were modeled to extract information on the frequency distribution of heat resistance within heat-challenged populations, and the frequency distribution characteristics of mean, mode, and variance were compared among treatment conditions. Significant differences in the frequency distribution data were compared with the D60-values. These data indicated that the presence and level of cross-protection is highly dependent on the physiological state of the cells and nutrient availability at the time of heat challenge. Such conditions should be considered to ensure that stressed pathogens in foods are destroyed or inactivated.

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Using measures of single‐cell physiology and physiological state to understand organismic aging

Aging Cell ◽

10.1111/acel.12424 ◽

2015 ◽

Vol 15 (1) ◽

pp. 4-13 ◽

Cited By ~ 6

Author(s):

Alexander Mendenhall ◽

Monica Driscoll ◽

Roger Brent

Keyword(s):

Single Cell ◽

Physiological State ◽

Cell Physiology ◽

Single Cell Physiology

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Delivery of Selective Agents via Time-Delayed Release Tablets Improves Recovery of Listeria monocytogenes Injured by Acid and Nitrite

Journal of Food Protection ◽

10.4315/0362-028x.jfp-13-315 ◽

2014 ◽

Vol 77 (5) ◽

pp. 772-780 ◽

Cited By ~ 1

Author(s):

ESMOND NYARKO ◽

DENNIS D'AMICO ◽

PATRICK MACH ◽

WENSHENG XIA ◽

CATHERINE DONNELLY

Keyword(s):

Listeria Monocytogenes ◽

Cell Populations ◽

Enrichment Broth ◽

Selective Enrichment ◽

Delayed Release ◽

Selective Agents ◽

Meat Samples ◽

Food Sample Analysis ◽

University Of Vermont ◽

The U.S

Listeria selective enrichment media are designed to enhance the isolation of the organism and increase the chances of detection. Drawbacks include the requirements for prolonged sample incubation (48 to 72 h) and manual addition of selective agents, which may be a source of contamination. Modified Listeria recovery broth (mLRB) is a proprietary enrichment medium formulated to facilitate the recovery of injured cells; its selective agents are incorporated into a format that allows delayed release until 6 h of incubation. We evaluated the change in cell populations over time for acid- and nitrite-injured Listeria monocytogenes in mLRB with the selective agents added manually at 0 h (mLRBS0) and 6 h (mLRBS6). Recovery of injured cells in mLRB plus time-delayed tablets (mLRBTD) was also compared with that in enrichment media recommended by the U.S. Department of Agriculture (University of Vermont broth), the U.S. Food and Drug Administration (buffered Listeria enrichment broth), and the International Organization for Standardization (demi-Fraser broth). Nitrite- or acid-injured Listeria at approximately 10 CFU/ml were inoculated into each broth medium, and Listeria populations were enumerated at various times from 12 to 48 h of incubation at 37°C. Analysis of variance revealed that acid-injured Listeria populations in mLRBS6 at 24 h were significantly higher (P < 0.05) than those in mLRBS0; however, the differences in populations on these two media were not significant for nitrite-injured cells. Cell populations of four strains of Listeria inoculated into mLRBTD were significantly higher at 24 h than when those strains were enriched in buffered Listeria enrichment broth, demi-Fraser broth, and University of Vermont broth. Comparison between artificially contaminated milk and meat samples with a four-strain cocktail of Listeria resulted in cell populations that were significantly higher (P < 0.05) at 24 h on mLRBTD for contaminated meat than on mLRB for contaminated milk. Delivery of selective agents via time-delayed release tablets into mLRB maximizes recovery of acid- and nitrite-injured Listeria and saves analyst time during food sample analysis.

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Comparison of EB and Fraser Enrichment Broths for the Detection of Listeria spp. and Listeria monocytogenes in Raw-Milk Dairy Products and Environmental Samples

Journal of Food Protection ◽

10.4315/0362-028x-59.11.1172 ◽

1996 ◽

Vol 59 (11) ◽

pp. 1172-1175 ◽

Cited By ~ 15

Author(s):

GEERTRUI M. VLAEMYNCK ◽

RENAAT MOERMANS

Keyword(s):

Listeria Monocytogenes ◽

Dairy Products ◽

Raw Milk ◽

Chain Reaction ◽

Enrichment Broth ◽

Selective Enrichment ◽

Isolation Frequency ◽

Detection And Identification ◽

Significant Difference ◽

Polymerase Chain

This study is a comparison of the isolation frequency of Listeria spp. and Listeria monocytogenes from selected naturally contaminated dairy products, especially soft smear-ripened cheeses from raw milk and samples of feces and rinse samples from the udder taken on the farm, by using an enrichment broth (EB) recommended by the International Dairy Federation and the U.S. Food and Drug Administration (IDF and FDA) or Fraser broth as the selective enrichment. Detection and identification were carried out according to the IDF protocols and a polymerase chain reaction technique. Listeria spp. were detected in 39.8% of the 570 samples while 15.3% were positive for L. monocytogenes. For cheese and curd samples, Fraser enrichment broth gave a statistically significant higher recovery for all Listeria spp. (26 to 21 %) as well as for L. monocytogenes in particular (9 to 1.4%). For raw milk and samples taken from feces and the udder rinse no significant difference was found between EB and Fraser broth. A combination of both enrichments resulted in an increase of recovery over all matrices by 15%.

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Detection of Listeria monocytogenes in Samples Containing Listeria innocua

Journal of Food Protection ◽

10.4315/0362-028x-57.12.1048 ◽

1994 ◽

Vol 57 (12) ◽

pp. 1048-1051 ◽

Cited By ~ 84

Author(s):

MICHAEL S. CURIALE ◽

CATHERINE LEWUS

Keyword(s):

Listeria Monocytogenes ◽

Growth Rates ◽

Environmental Samples ◽

Listeria Innocua ◽

Enrichment Broth ◽

Selective Media ◽

Common Culture ◽

Generation Times ◽

Secondary Enrichment ◽

Culture Procedure

A common culture procedure for the detection of Listeria monocytogenes in meats and environmental samples was evaluated in a multilaboratory study using samples inoculated with both Listeria monocytogenes and Listeria innocua. Listeria monocytogenes was recovered from 5.4% of beef broth samples containing between 140 and 1400 L. monocytogenes cells per 25-ml sample in the presence of twice as many L. innocua cells; whereas L. innocua was recovered from all of the samples. Listeria monocytogenes was isolated from 100% of the samples when L. innocua was absent. Similar results were obtained for swab samples containing both L. monocytogenes and L. innocua. Listeria monocytogenes was recovered from 31% of the swabs containing 4.8 L. monocytogenes cells per swab and from 0% of the swabs containing the same number of L. monocytogenes cells and 4 L. innocua cells per swab. When the ratios of L. monocytogenes to L. innocua were 12:1, 120:1 and 1200:1, L. monocytogenes was isolated from 38%, 92% and 85% of the swabs, respectively. The recovery rates were consistent with the differences in growth rates for the two organisms in selective media. The generation times for L. monocytogenes were 74 min in primary enrichment broth and 105 min in modified secondary enrichment broth. Listeria innocua posted generation times of 53 and 81 min in the same two enrichment broths.

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Simultaneous Growth of Listeria monocytogenes and Listeria innocua

Journal of Food Protection ◽

10.4315/0362-028x-56.7.616 ◽

1993 ◽

Vol 56 (7) ◽

pp. 616-618 ◽

Cited By ~ 77

Author(s):

RUTH L. PETRAN ◽

KATHERINE M. J. SWANSON

Keyword(s):

Listeria Monocytogenes ◽

Yeast Extract ◽

Environmental Samples ◽

Culture Media ◽

Listeria Innocua ◽

Enrichment Broth ◽

University Of Vermont ◽

Simultaneous Growth

Listeria spp. have been isolated from a wide variety of sources, and in many situations Listeria innocua is more commonly found than Listeria monocytogenes. Growth of three L. monocytogenes strains was studied when inoculated simultaneously with a rhamnose negative L. innocua strain into culture media and cheese sauce. Fraser broth (FB), Trypticase™ soy broth plus 0.6% yeast extract (TSB-YE), University of Vermont medium (UVM) modified Listeria enrichment broth, and cheese sauce were inoculated (ca. 102 cells per ml) and incubated for 24 h; FB, TSB-YE, and cheese sauce at 35°C, UVM at 30°C. Growth of four rhamnose-positive, L. innocua strains was also studied in culture media. Growth of L. monocytogenes was similar to that for L. innocua in TSB-YE or cheese sauce. However, in FB and UVM, L. innocua populations were significantly higher than L. monocytogenes. This occurred when media were inoculated individually or simultaneously. This may explain in part why L. innocua is isolated more frequently than L. monocytogenes from foods and environmental samples.

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