Heat Resistance of Listeria monocytogenes

2001 ◽  
Vol 64 (3) ◽  
pp. 410-429 ◽  
Author(s):  
M. ELLIN DOYLE ◽  
ALEJANDRO S. MAZZOTTA ◽  
TIM WANG ◽  
DANA W. WISEMAN ◽  
VIRGINIA N. SCOTT
Keyword(s):  
Listeria Monocytogenes ◽  
Heat Resistance ◽  
Foodborne Pathogens ◽  
Fruits And Vegetables ◽  
Culture Media ◽  
Salt Content ◽  
Growth Conditions ◽  
Salmonella Spp ◽  
Different Strains ◽  
Resistance Data

The heat resistance data on Listeria monocytogenes in culture media and foods are summarized. Most heat resistance data for foods have been obtained in dairy, meat, poultry, and egg products. Limited data have been published on seafood, fruits, and vegetables. The methodologies employed have evolved over time; hence data from earlier experiments are not directly comparable to more recent studies. Many factors influence the heat resistance of L. monocytogenes. Variation exists among different strains in their ability to withstand heat treatment. In addition, heat resistance is influenced by age of the culture, growth conditions, recovery media, and characteristics of foods such as salt content, aw, acidity, and the presence of other inhibitors. Listeriae are more heat resistant than most other nonspore-forming foodborne pathogens, and thus, processing recommendations based on data from experiments with Salmonella spp. or pathogenic Escherichia coli may not be sufficient to eliminate similar numbers of L. monocytogenes. The data provided in this review may prove useful for food processors in determining appropriate times and temperatures for producing foods free of vegetative pathogens.

Bacteriological Survey of Ready-to-Eat Lettuce, Fresh-Cut Fruit, and Sprouts Collected from the Swiss Market

2012 ◽  
Vol 75 (7) ◽  
pp. 1338-1341 ◽  
Author(s):  
D. ALTHAUS ◽  
E. HOFER ◽  
S. CORTI ◽  
A. JULMI ◽  
R. STEPHAN
Keyword(s):  
Foodborne Pathogens ◽  
Fruits And Vegetables ◽  
Summer Season ◽  
Central Importance ◽  
Salmonella Spp ◽  
E Coli ◽  
Indicator Microorganism ◽  
Fresh Vegetables ◽  
Fresh Cut ◽  
Public Health Protection

The consumption of ready-to-eat fresh vegetables has increased significantly in the recent decades. So far, no data are available on the bacteriological burden and the prevalence of foodborne pathogens in ready-to-eat lettuce, fresh-cut fruit, and sprouts on the Swiss market. This study was based on investigations carried out during 2 months of the summer season in 2011. Samples of 142 salads, 64 fresh-cut fruit, and 27 sprouts were included in this study. Escherichia coli, an indicator microorganism for fecal contamination, was only found in 5 lettuce samples, with amounts ranging between 2 and 3 log CFU/g. No Salmonella spp. were detected from any of the 233 samples analyzed in this study, and a low occurrence was found for contamination with L. monocytogenes, Shiga toxin–producing E. coli, enteropathogenic E. coli, and Cronobacter. From the results of the present study, we conclude that even in a country where the use of chlorine solutions to sanitize fruits and vegetables in the fresh-cut industry is not allowed, it is possible to produce ready-to-eat lettuce, fresh-cut fruit, and sprouts with high microbiological standards. Strict maintenance of good practices of hygiene at preharvest, harvest, and postharvest levels is of central importance to ensure both public health protection and product quality.

scholarly journals Growth inhibition of foodborne pathogens in camel milk: Staphylococcus aureus, Listeria monocytogenes, Salmonella spp. and E. coli O157:H7

2017 ◽  
Vol 35 (No. 4) ◽  
pp. 311-320 ◽  
Author(s):  
Abusheliabi Aisha ◽  
Al-Holy Murad A ◽  
Al-Rumaithi Hind ◽  
Al-Khaldi Sufian ◽  
Al-Nabulsi Anas A ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Listeria Monocytogenes ◽  
Growth Inhibition ◽  
Foodborne Pathogens ◽  
Bovine Milk ◽  
Growth Patterns ◽  
Camel Milk ◽  
Salmonella Spp ◽  
E Coli ◽  
Milk Samples

The growth behaviour of foodborne pathogens (Staphylococcus aureus, Listeria monocytogenes, E. coli O157:H7 and Salmonella spp.) was investigated in pasteurised camel milk and compared with pasteurised bovine milk at different incubation temperatures. This study also aimed to compare the growth patterns of these four foodborne pathogens in pasteurised and raw camel milk. Pasteurised or raw camel milk and pasteurised bovine milk were separately inoculated with a cocktail of three strains of each foodborne pathogen. The inoculated milk samples were incubated at 10, 25, and 37°C. The total bacterial count (TBC) in raw milk and the total thermoduric bacteria count (TDB) in pasteurised milk samples were monitored. Greater growth inhibition rates of four pathogens were obtained for the pasteurised camel milk compared to the pasteurised bovine milk. Raw and pasteurised camel milk exerted bacteriostatic effect against all tested pathogens, particularly for the first 8 h of incubation in milk at the different temperatures. Pasteurised camel milk exerted an inhibitory activity that was equivalent to that of raw camel milk.

scholarly journals Listeria monocytogenes: A CONSIDERABLE PATHOGENIC MICROORGANISM OF CONCERN IN MINIMALLY PROCESSED FRUITS AND VEGETABLES

2017 ◽  
Vol 6 (1) ◽  
pp. 1
Author(s):  
Helen C D Tuhumury
Keyword(s):  
Listeria Monocytogenes ◽  
Foodborne Pathogens ◽  
Fruits And Vegetables ◽  
Significant Risk ◽  
Pathogenic Microorganism ◽  
Minimally Processed ◽  
Growth And Survival ◽  
Food Borne ◽  
Increasing Demand

The increasing demand of minimally processed fruits and vegetables signify a challenge to make them stable and safe to be consumed. The processing of this type of product may contribute higher risks of food borne illnesses. One of the foodborne pathogens in minimally processed fruits and vegetables is Listeria monocytogenes. The importance of understanding the characteristics of L. monocytogenes will help to determine how this microorganism occurs, grows, and survives in minimally processed fruits and vegetables. Proper and suitable methods to reduce L. monocytogenes so that it can not pose a significant risk to cause disease therefore are able to be determined according to the model of the growth and survival of L. monocytogenes in minimally processed fruits and vegetables.

scholarly journals The DegU Orphan Response Regulator Contributes to Heat Stress Resistance in Listeria monocytogenes

2021 ◽  
Vol 11 ◽  
Author(s):  
Changyong Cheng ◽  
Feng Liu ◽  
Haobo Jin ◽  
Xiangfei Xu ◽  
Jiali Xu ◽  
...  
Keyword(s):  
Heat Stress ◽  
Listeria Monocytogenes ◽  
Heat Shock ◽  
Heat Resistance ◽  
Foodborne Pathogens ◽  
Response Regulator ◽  
Heat Shock Stress ◽  
Heat Stress Resistance ◽  
Shock Proteins ◽  
Shed Light

Listeria monocytogenes is more heat-resistant than most other non-spore-forming foodborne pathogens, posing a severe threat to food safety and human health, particularly during chilled food processing. The DegU orphan response regulator is known to control heat resistance in L. monocytogenes; however, the underlying regulatory mechanism is poorly understood. Here, we show that DegU contributes to L. monocytogenes exponential growth under mild heat-shock stress. We further demonstrate that DegU directly senses heat stress through autoregulation and upregulates the hrcA-grpE-dnaK-dnaJ operon, leading to increased production of heat-shock proteins. We also show that DegU can directly regulate the expression of the hrcA-grpE-dnaK-dnaJ operon. In conclusion, our results shed light on the regulatory mechanisms underlying how DegU directly activates the hrcA-grpE-dnaK-dnaJ operon, thereby regulating heat resistance in L. monocytogenes.

Antimicrobial Resistance Profile of Salmonella and Listeria monocytogenes Isolated from Products Marketed on the Border of Brazil with Argentina and Uruguay

2020 ◽  
Vol 83 (11) ◽  
pp. 1941-1946
Author(s):  
JULIANO GONÇALVES PEREIRA ◽  
VANESSA MENDONÇA SOARES ◽  
LEONARDO ERENO TADIELO ◽  
TASSIANA RAMIRES ◽  
WLADIMIR PADILHA da SILVA
Keyword(s):  
Listeria Monocytogenes ◽  
Antimicrobial Resistance ◽  
Foodborne Pathogens ◽  
Penicillin G ◽  
Diffusion Method ◽  
Salmonella Spp ◽  
Disk Diffusion Method ◽  
Resistance Profile ◽  
Antimicrobial Resistance Profile ◽  
Antimicrobial Resistance Genes

ABSTRACT We aimed to perform serotyping and the antimicrobial resistance profile of Salmonella spp. and Listeria monocytogenes strains isolated from raw meats imported illegally into Brazil along the borders of Argentina and Uruguay. Distinct isolates of Salmonella spp. (n = 6) and L. monocytogenes (n = 25) obtained from 270 of these food products of earlier work were serotyped and tested for antimicrobial resistance by agar disk diffusion method. For strains that were considered phenotypically resistant, antimicrobial resistance genes were investigated: strA, strB, floR, tetA, tetB, blaZ, blaTEM, ermB, ermC, and ereB to Salmonella sp. and blaZ and mecA to L. monocytogenes. All Salmonella isolates were identified as Salmonella Infantis; they were multidrug resistant and harbored the genes blaTEM (n = 6), strA (n = 1), strB (n = 1), floR (n = 1), ermB (n = 1), tetA (n = 3), and tetB (n = 3). L. monocytogenes isolates belonged to serovars 1/2a (n = 1), 1/2b (n = 14), 1/2c (n = 2), and 4b (n = 8), showed resistance only to penicillin G (n = 12), and did not show the blaZ and mecA genes. The results demonstrated that illegal foods that are commercialized in the Brazilian international border with Argentina and Uruguay may harbor foodborne pathogens, and some of them have multidrug resistance characteristics, such as Salmonella, emphasizing the need for greater control of international food transit in Brazil, especially in the region evaluated. HIGHLIGHTS

Fate of Listeria monocytogenes, Salmonella Typhimurium DT104, and Escherichia coli O157:H7 in Labneh as a Pre- and Postfermentation Contaminant

2000 ◽  
Vol 63 (5) ◽  
pp. 608-612 ◽  
Author(s):  
MOHSEN S. ISSA ◽  
ELLIOT T. RYSER
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Salmonella Typhimurium ◽  
Foodborne Pathogens ◽  
Storage Temperature ◽  
Starter Culture ◽  
Salt Content ◽  
Health Concern ◽  
Escherichia Coli O157 ◽  
E Coli

Commercially pasteurized milk (∼2% milkfat) was heated at 85 to 87°C/30 min, inoculated to contain 2,000 to 6,000 CFU/ml of Listeria monocytogenes, Salmonella Typhimurium DT104, or Escherichia coli O157:H7, cultured at 43°C for 4 h with a 2.0% (wt/wt) commercial yogurt starter culture, stored 12 to 14 h at 6°C, and centrifuged to obtain a Labneh-like product. Alternatively, traditional salted and unsalted Labneh was prepared using a 3.0% (wt/wt) starter culture inoculum, similarly inoculated after manufacture with the aforementioned pathogens, and stored at 6°C and 20°C. Throughout fermentation, Listeria populations remained unchanged, whereas numbers of Salmonella increased 0.33 to 0.47 logs during the first 2 h of fermentation and decreased thereafter. E. coli populations increased 0.46 to 1.19 logs during fermentation and remained that these levels during overnight cold storage. When unsalted and salted Labneh were inoculated after manufacture, Salmonella populations decreased >2 logs in all samples after 2 days, regardless of storage temperature, with the pathogen no longer detected in 4-day-old samples. Numbers of L. monocytogenes decreased from 2.48 to 3.70 to <1.00 to 1.95 logs after 2 days with the pathogen persisting up to 15 days in one lot of salted/unsalted Labneh stored at 6°C. E. coli O157:H7 populations decreased from 3.39 to 3.7 to <1.00 to 2.08 logs during the first 2 days, with the pathogen no longer detected in any 4-dayold samples. Inactivation rates for all three pathogens in Labneh were unrelated to storage temperature or salt content. Unlike L. monocytogenes that persisted up to 15 days in Labneh, rapid inactivation of Salmonella Typhimurium DT104 and E. coli O157:H7 suggests that these emerging foodborne pathogens are of less public health concern in traditional Labneh.

scholarly journals Strain and Growth Conditions may Regulate Resistance of Listeria monocytogenes Biofilms to Benzalkonium Chloride

2020 ◽  
Vol 10 (3) ◽  
pp. 988 ◽  
Author(s):  
Lourenço Bonneville ◽  
Sagrario Ortiz ◽  
Vera Maia ◽  
Luisa Brito ◽  
Joaquín V. Martínez-Suárez
Keyword(s):  
Listeria Monocytogenes ◽  
Foodborne Pathogens ◽  
Benzalkonium Chloride ◽  
Culture Medium ◽  
Wild Type Strain ◽  
Inhibitory Concentration ◽  
Resistant Mutant ◽  
Growth Conditions ◽  
Processing Plants ◽  
Mutant Derivative

Listeria monocytogenes is one of the main foodborne pathogens. The formation of biofilms by L. monocytogenes contributes to its resistance to disinfectants, which represents a serious risk for food production plants. The aim of this study was to compare the effect of sub-inhibitory concentrations of benzalkonium chloride (BAC) (1.25 or 2.5 mg/L) on biofilm production and on biofilm reduction after exposure to an inhibitory concentration of BAC (1280 mg/L) in two isogenic L. monocytogenes strains: the BAC-sensitive wild-type strain S2-1 and its BAC-resistant mutant derivative S2BAC, which presented a multidrug resistance phenotype. The biofilm-forming ability of the strains under different BAC concentrations was evaluated by the resazurin method using polystyrene microplates. The biofilm reduction after BAC exposure was evaluated by using stainless steel coupons (SSCs). When the resazurin method was used, S2BAC produced significantly more biofilm in the presence of a sub-inhibitory concentration of BAC compared to that in the culture medium without BAC (p < 0.05). When the SSC method was used, the presence of sub-inhibitory concentrations of BAC resulted in a higher resistance of the biofilm for S2BAC compared to that in the culture medium without BAC (p < 0.05). This was not observed with the sensitive S2-1 strain. These results suggest that biofilm behavior depends on the strain and sub-inhibitory concentrations of disinfectants and may explain the ability of certain isolates to persist in niches of food processing plants.

scholarly journals MIR spectroscopy as alternative method for further confirmation of foodborne pathogens Salmonella spp. and Listeria monocytogenes

2018 ◽  
Vol 55 (10) ◽  
pp. 3971-3978 ◽  
Author(s):  
Catarina Moreirinha ◽  
Joana Trindade ◽  
Jorge A. Saraiva ◽  
Adelaide Almeida ◽  
Ivonne Delgadillo
Keyword(s):  
Listeria Monocytogenes ◽  
Foodborne Pathogens ◽  
Salmonella Spp ◽  
Mir Spectroscopy ◽  
Alternative Method

scholarly journals Molecular characterization of Salmonella spp. and Listeria monocytogenes strains from biofilms in cattle and poultry slaughterhouses located in the federal District and State of Goiás, Brazil

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0259687
Author(s):  
Emilia Fernanda Agostinho Davanzo ◽  
Rebecca Lavarini dos Santos ◽  
Virgilio Hipólito de Lemos Castro ◽  
Joana Marchesini Palma ◽  
Bruno Rocha Pribul ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Molecular Characterization ◽  
Foodborne Pathogens ◽  
Federal District ◽  
Multidrug Resistant ◽  
Animal Origin ◽  
Meat Production ◽  
Salmonella Spp

Listeria monocytogenes and Salmonella spp. are considered important foodborne pathogens that are commonly associated with foods of animal origin. The aim of this study was to perform molecular characterization of L. monocytogenes and Salmonella spp. isolated from biofilms of cattle and poultry slaughterhouses located in the Federal District and State of Goiás, Brazil. Fourteen L. monocytogenes isolates and one Salmonella sp. were detected in poultry slaughterhouses. No isolates were detected in cattle slaughterhouses. All L. monocytogenes isolates belonged to lineage II, and 11 different pulsotypes were detected. Pulsed-field gel electrophoresis analysis revealed the dissemination of two strains within one plant, in addition to the regional dissemination of one of them. The Salmonella isolate was identified via whole genome sequencing as Salmonella enterica serovar Minnesota ST548. In the sequence analysis, no premature stop codons were detected in the inlA gene of Listeria. All isolates demonstrated the ability to adhere to Caco-2 cells, while 50% were capable of invading them. Antimicrobial resistance was detected in 57.1% of the L. monocytogenes isolates, and resistance to sulfonamide was the most common feature. The tetC, ermB, and tetM genes were detected, and four isolates were classified as multidrug-resistant. Salmonella sp. was resistant to nine antimicrobials and was classified as multidrug-resistant. Resistance genes qnrB19, blaCMY-2, aac(6’)-Iaa, sul2, and tetA, and a mutation in the parC gene were detected. The majority (78.5%) of the L. monocytogenes isolates were capable of forming biofilms after incubation at 37°C for 24 h, and 64.3% were capable of forming biofilms after incubation at 12°C for 168 h. There was no statistical difference in the biofilm-forming capacity under the different evaluated conditions. Salmonella sp. was capable of forming biofilms at both tested temperatures. Biofilm characterization was confirmed by collecting the samples consistently, at the same sampling points, and by assessing biofilm formation in vitro. These results highlight the potential risk of cross-contamination in poultry slaughterhouses and the importance of surveillance and pathogen control maintenance programs within the meat production industry.

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