scholarly journals Differential Listeria monocytogenes Strain Survival and Growth in Katiki, a Traditional Greek Soft Cheese, at Different Storage Temperatures

2009 ◽  
Vol 75 (11) ◽  
pp. 3621-3626 ◽  
Author(s):  
Dafni-Maria Kagkli ◽  
Vassilios Iliopoulos ◽  
Virginia Stergiou ◽  
Anna Lazaridou ◽  
George-John Nychas
Keyword(s):  
Listeria Monocytogenes ◽  
Pulsed Field Gel Electrophoresis ◽  
Temperature Dependent ◽  
Protected Designation Of Origin ◽  
Soft Cheese ◽  
Different Temperatures ◽  
The Subject ◽  
Survival And Growth ◽  
Different Strains ◽  
Storage Temperatures

ABSTRACT Katiki Domokou is a traditional Greek cheese, which has received the Protected Designation of Origin recognition since 1994. Its microfloras have not been studied although its structure and composition may enable (or even favor) the survival and growth of several pathogens, including Listeria monocytogenes. The persistence of L. monocytogenes during storage at different temperatures has been the subject of many studies since temperature abuse of food products is often encountered. In the present study, five strains of L. monocytogenes were aseptically inoculated individually and as a cocktail in Katiki Domokou cheese, which was then stored at 5, 10, 15, and 20°C. Pulsed-field gel electrophoresis was used to monitor strain evolution or persistence during storage at different temperatures in the case of the cocktail inoculum. The results suggested that strain survival of L. monocytogenes was temperature dependent since different strains predominated at different temperatures. Such information is of great importance in risk assessment studies, which typically consider only the presence or absence of the pathogen.

Growth ofListeria monocytogenesin Camembert and other soft cheeses at refrigeration temperatures

1993 ◽  
Vol 60 (3) ◽  
pp. 421-429 ◽  
Author(s):  
Jonathan P. Back ◽  
Sarah A. Langford ◽  
Rohan G. Kroll
Keyword(s):  
Listeria Monocytogenes ◽  
Temperature Dependent ◽  
Ripening Process ◽  
Significant Growth ◽  
Soft Cheese ◽  
French And English ◽  
Dependent Growth ◽  
Rates Of Growth ◽  
Storage Temperatures

SummaryListeria monocytogenessurvived and, under most conditions, multiplied when inoculated directly into the cheese milk of laboratory made Camembert cheeses. The rate and extent of growth was reduced at lower storage temperatures. Significantly higher rates of growth occurred at the surface compared with the centre of the cheeses, and these were probably associated with increased pH and proteolysis at the cheese surface due to the mould ripening process. Similar results were obtained with Camembert cheeses surface inoculated after manufacture. There was also temperature-dependent growth of List, monocytogenes on a range of inoculated commercially manufactured soft cheeses. Significant growth occurred in Cambazola, French and English Brie, blue and white Lymeswold, French Camembert and Brie with garlic. Little if any growth occurred in blue and white Stilton, Mycella, Chaume and full fat soft cheese with garlic and herbs at the temperatures examined.

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 < 0.05) at 25°C than at 4 and 10°C. In general, the order of effectiveness of treatments was HW-LA > LA > LA-HW > HW > 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.

Human isolates ofListeria monocytogenesin Sweden during half a century (1958–2010)

2014 ◽  
Vol 142 (11) ◽  
pp. 2251-2260 ◽  
Author(s):  
G. LOPEZ-VALLADARES ◽  
W. THAM ◽  
V. SINGH PARIHAR ◽  
S. HELMERSSON ◽  
B. ANDERSSON ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Gel Electrophoresis ◽  
Pulsed Field Gel Electrophoresis ◽  
Pfge Type ◽  
Pulsed Field ◽  
Smoked Salmon ◽  
Soft Cheese ◽  
Cheese Production

SUMMARYIsolates ofListeria monocytogenes(n = 932) isolated in Sweden during 1958–2010 from human patients with invasive listeriosis were characterized by serotyping and pulsed-field gel electrophoresis (PFGE) (AscI). Of the 932 isolates, 183 different PFGE types were identified, of which 83 were each represented by only one isolate. In all, 483 serovar 1/2a isolates were distributed over 114 PFGE types; 90 serovar 1/2b isolates gave 32 PFGE types; 21 serovar 1/2c isolates gave nine PFGE types; three serovar 3b isolates gave one PFGE type; and, 335 serovar 4b isolates gave 31 PFGE types. During the 1980s in Sweden, several serovar 4b cases were associated with the consumption of European raw soft cheese. However, as cheese-production hygiene has improved, the number of 4b cases has decreased. Since 1996, serovar 1/2a has been the dominantL. monocytogenesserovar in human listeriosis in Sweden. Therefore, based on current serovars and PFGE types, an association between human cases of listeriosis and the consumption of vacuum-packed gravad and cold-smoked salmon is suggested.

scholarly journals More than one variant ofListeria monocytogenesisolated from each of two human cases of invasive listeriosis

2006 ◽  
Vol 135 (5) ◽  
pp. 854-856 ◽  
Author(s):  
W. THAM ◽  
G. LOPEZ VALLADARES ◽  
S. HELMERSSON ◽  
A. ÖSTERLUND ◽  
M.-L. DANIELSSON-THAM
Keyword(s):  
Listeria Monocytogenes ◽  
Molecular Typing ◽  
Gel Electrophoresis ◽  
Blood Cultures ◽  
Pulsed Field Gel Electrophoresis ◽  
The Other ◽  
Dna Profile ◽  
Pulsed Field ◽  
Different Strains

SUMMARYTwo variants ofListeria monocytogeneswere isolated from blood cultures from each of two patients with listeriosis. Each variant displayed a two-band difference in DNA profile from the other by pulsed-field gel electrophoresis. Although this difference in profile is insufficient to distinguish clearly between the variants, the possibility of co-infection with different strains ofL. monocytogenesneeds to be considered. We suggest that more than one colony should be selected for molecular typing to aid interpretation during investigation of the sources and routes ofListeriainfection.

Comparison of Media and Sampling Locations for Isolation of Listeria monocytogenes in Queso Fresco Cheese

2006 ◽  
Vol 69 (9) ◽  
pp. 2151-2156 ◽  
Author(s):  
CHIA-MIN LIN ◽  
LEI ZHANG ◽  
MICHAEL P. DOYLE ◽  
BALA SWAMINATHAN
Keyword(s):  
Listeria Monocytogenes ◽  
Storage Temperature ◽  
Epidemiologic Studies ◽  
Detection Methods ◽  
Health Concern ◽  
Public Health Concern ◽  
Sampling Locations ◽  
Soft Cheese ◽  
Regulatory Analysis ◽  
Storage Temperatures

Listeriosis associated with Hispanic-style soft cheese is an ongoing public health concern. Although rapid detection methods based on molecular and immunological technologies have been applied successfully for detecting Listeria monocytogenes in foods, obtaining isolates of the pathogen is a critical procedure for epidemiologic studies and regulatory analysis. Oxford agar, a medium recommended by the U.S. Food and Drug Administration Bacteriological Analytical Manual (BAM) to isolate L. monocytogenes from cheese, is unable to differentiate L. monocytogenes from other Listeria species. Hence, two selective isolation media, L. monocytogenes blood agar (LMBA) and Rapid 'L. mono agar (RLMA), were compared with Oxford agar for isolating L. monocytogenes from cheese. Queso fresco cheese was inoculated at 100 or 101 CFU/g with a five-strain mixture of L. monocytogenes or with the five-strain L. monocytogenes mixture and Listeria innocua. Cheese samples were stored at 21, 12, and 4°C and Listeria counts were determined at 3, 7, and 10 days; 7, 10, 14, 21 days; and 2, 4, 8, and 12 weeks postinoculation, respectively. Surface and interior cheese samples as well as liquid exudate produced during storage were assayed individually to determine differences in Listeria contamination at different sampling locations. L. monocytogenes was more easily differentiated from L. innocua on RLMA than LMBA and Oxford agar. Similar L. monocytogenes counts (ca. 104 CFU/g) were obtained on the last sampling day on the surface and interior of cheese samples (P > 0.05) for all storage temperatures and both initial inoculation levels, but smaller cell numbers were detected in the exudate produced during storage. In addition, simultaneous inoculation of L. innocua with L. monocytogenes did not affect the final L. monocytogenes counts in the cheese. The amount of exudate released from the cheese and decrease of pH correlated with storage temperature. More exudate was produced and a greater decrease of pH occurred at 21°C than at 12 or 4°C. Our results indicate that RLMA is a suitable medium for isolating L. monocytogenes from queso fresco cheese. Higher counts of L. monocytogenes were obtained from surface and interior samples of cheese than from the exudate of the cheese during storage. In addition, pH may be a useful indicator of improperly stored queso fresco cheese.

Survival and Growth of Listeria monocytogenes and Escherichia coli O157:H7 in Ready-to-Eat Iceberg Lettuce Washed in Warm Chlorinated Water

2002 ◽  
Vol 65 (3) ◽  
pp. 459-464 ◽  
Author(s):  
PASCAL DELAQUIS ◽  
SANDRA STEWART ◽  
SANDRA CAZAUX ◽  
PETER TOIVONEN
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Iceberg Lettuce ◽  
Before And After ◽  
Survival And Growth ◽  
Spoilage Microflora ◽  
Storage Temperatures

Cut iceberg lettuce inoculated with Escherichia coli O157:H7 and Listeria monocytogenes before and after washing for 3 min in cold (4°C) and warm (47°C) water containing 100 mg/liter total chlorine was stored at 1 and 10°C in oxygen-permeable film packages (6,000 to 8,000 cc/m2/24 h). Cold chlorinated water was detrimental to the survival of E. coli O157: H7 and L. monocytogenes at both storage temperatures. In contrast, washing in warm chlorinated water favored the growth of both pathogens in lettuce stored at 10°C. There was no evidence of a relationship between the magnitude of spoilage microflora and the fate of either bacterium.

Capacity of Listeria monocytogenes Strains from the 2011 Cantaloupe Outbreak To Adhere, Survive, and Grow on Cantaloupe

2016 ◽  
Vol 79 (5) ◽  
pp. 757-763 ◽  
Author(s):  
MIRA RAKIC MARTINEZ ◽  
JASON OSBORNE ◽  
VICTOR OLADIMEJI JAYEOLA ◽  
VERA KATIC ◽  
SOPHIA KATHARIOU
Keyword(s):  
Listeria Monocytogenes ◽  
Growth Potential ◽  
Sterile Water ◽  
Different Temperatures ◽  
Reduce Risk ◽  
Biological Attributes ◽  
Different Strains

ABSTRACT The 2011 listeriosis outbreak attributed to whole cantaloupe involved several genetically distinct strains of serotypes 1/2a and 1/2b that had not been previously reported in invasive listeriosis outbreaks. Here we investigated the potential of strains from the 2011 cantaloupe outbreak to adhere, survive, and grow on cantaloupe rind and flesh and in juice extracted from cantaloupe at different temperatures (4, 8, and 25°C). All strains were able to adhere and grow, with ~10-fold increases after 7 days at 4 or 8°C and after 24 h at 25°C, with a propensity for more growth on rind than on flesh or in extract. No significant differences in growth potential were noted among the different strains or between them and unrelated strains from other listeriosis outbreaks involving celery, deli meats, or hot dogs. Similarly to the cantaloupe outbreak strains, these other strains exhibited greater propensity for growth on rind than on flesh or in extract. Rinsing of cantaloupe fragments in sterile water resulted in temporary reductions of the populations by 50- to 100-fold, suggesting the potential of such washing to reduce risk if the produce is promptly consumed. The absence of marked differences in adherence or growth between the cantaloupe outbreak strains and strains from other outbreaks highlights the need to further characterize the 2011 cantaloupe outbreak strains and elucidate potential biological attributes that contributed to their implication in the outbreak.

Temperature, pH, and Strain of Pathogen as Factors Affecting Inactivation of Listeria monocytogenes by Chlorine

1988 ◽  
Vol 51 (8) ◽  
pp. 622-625 ◽  
Author(s):  
SOUZAN E. EL-KEST ◽  
ELMER H. MARTH
Keyword(s):  
Listeria Monocytogenes ◽  
Sodium Hypochlorite ◽  
Initial Population ◽  
Sodium Hypochlorite Solution ◽  
Factors Affecting ◽  
Hypochlorite Solution ◽  
Ph Values ◽  
Different Temperatures ◽  
Different Strains

Listeria monocytogenes strain Scott-A was treated with 1 ppm available chlorine at different temperatures and pH values. Different strains of L. monocytogenes (California, Scott-A and V7) were also exposed to 1 ppm available chlorine at pH 7 and 25°C. The initial population of L. monocytogenes was 1 × 108 to 3.2 × 108 CFU/ml of sodium hypochlorite solution. Survival of L. monocytogenes was measured by surface-plating (on tryptose agar) samples taken at intervals of 30 s to 1 h of exposure to hypochlorite solution. Larger numbers of L. monocytogenes strain Scott-A survived at 25 than at 35°C. The smallest number was observed when cells were exposed to the hypochlorite solution at 5°C. The higher the pH values, in the range of 5 to 9, the greater were the numbers of survivors of L. monocytogenes strain Scott-A. Of the strains studied, California was the most resistant, while V7 was the least resistant to the hypochlorite solution.

Sign in / Sign up

Export Citation Format

Share Document