جستجوی مقالات مرتبط با کلیدواژه « لیستریا مونوسیتوژنز » در نشریات گروه « پزشکی »

Mortality rate of Listeria infection is high and has been reported to be up to 30%. In this regard, the present study aimed to provide more information about food sources contaminated with the Listeria monocytogenes and offer suitable strategies to control this pathogen in supply centers, slaughterhouses, and processing centers.

Results of investigations on the prevalence of L. monocytogenes in food (seafood and aquatic products, red meat, poultry, and dairy products) during 2010-2023 were reviewed. In total, 61 acceptable studies were involved in the present research. After the selection of papers, their key results were extracted, including the prevalence of Listeria monocytogenes, cultivation method, sample type, and sampling location.

Listeria monocytogenes is prevalent in all types of seafood products, red meat, poultry, dairy products, and vegetables, as well as ready-to-eat and ready-to-cook foods. Consuming raw and undercooked foods contaminated with animal and human feces and direct contact with feces can cause Listeria infection in humans. L. monocytogenes is sensitive to amoxicillin, ampicillin, penicillin, and gentamicin antibiotics; therefore, these antibiotics can be used for listeriosis treatment.

In previous studies, the importance of traditional meat and dairy supply centers in L. monocytogenes transmission has been addressed to a lesser extent. It can be concluded that appropriate standards should be developed and applied to control this food pathogen by regulatory systems. In addition, regular and periodic monitoring of food products and providing necessary training to people about how to prevent food poisoning can play an effective role in reducing listeriosis.

Reactive oxygen species cause disease by damaging the chemical compounds in our body. On the other hand, drug resistance is becoming a serious issue in infection treatment, globally. Ginkgo biloba has many therapeutically features. The objective of this study was to evaluate antioxidant and antibacterial activity of Iranian Ginkgo’s leaf extracts.

In this experimental study, aqueous, ethanolic (%70) and methanolic (%80) extracts were made using Ginkgo. Total Phenolic and Flavonoids Content were measured by folin– ciocalteu reagent and Chloride Aluminum color assays. The extracts’ antioxidant activity was assessed by their potential in scavenging DPPH free radicals. Disc Diffusion assay was carried out to test antibacterial potency against two strains of bacteria (Enterococcus faecalis, Listeria monocytogenes). Data analysis was performed using factorial experiment within a completely randomized design. SPSS version 16 software and Duncan's multiple range tests were used to compare the means.

Based on results, all three extracts contained extensive amount of phenolic and especially flavonoid compounds with methanolic extract being the richest in phenolic and flavonoids while aqueous extract having the least of these compounds. The most antioxidant activity was found in methanolic extract of 300 mg/mL concentration with %84.73 (P<0.05) and the least was in aqueous extract of 40 mg/mL with %18.17 (P<0.05) ROS scavenging rate, this result was proportional to the measured bioactive components of the extracts. Antibacterial activity in 200 mg/mL concentration of methanolic extract was maximum against Enterococcus faecalis while it was minimum at 50 mg/µl concentration of aqueous extract against Listeria monocytogenes strain. Antibacterial activity of all three extracts was found out to be concentration dependent.

The results indicated that Ginkgo leaves are rich in phenolic and flavonoids contents that may be reason behind their notable antioxidant and antibacterial activity. Thus, Ginkgo could be a treasure trove of antioxidants and therapeutic compounds. However, more studies are required in regard to Ginkgo’s various characteristics.

Listeria monocytogenes leads to listeriosis in humans through the consumption of ready-to-eat foods. Older adults, immunocompromised patients, pregnant women, and newborns are at the highest risk for this infection. To detect probiotic bacteria with an inhibitory activity against L. monocytogenes, we evaluated the inhibitory effect of Lactococcus lactis on the growth and invasion of L. monocytogenes.

In this study, we used the L. monocytogenes ATCC 7644 strain and the L. lactis PTCC 1336 probiotic strain. To investigate the inhibitory effects of L. lactis on the growth of pathogenic L. monocytogenes, we employed the well diffusion agar method, and to investigate its inhibitory effect on invasion by this bacterium, we conducted a co-culture with Caco-2 human enterocyte cells.

The results showed that L. lactis in concentrations of 0.25, 0.5, and 1 had antimicrobial properties against L. monocytogenes. With increasing concentration, the inhibitory effect on this pathogen increased. In addition, L. lactis showed an inhibitory effect on the L. monocytogenes invasion of Caco-2 cells. Therefore, in the concentration of 1, L. lactis decreased the number of bacteria by reducing the invasion of the cells by Listeria from log 108 to log 102; in the concentration of 0.5, from log 108 to log 103; and in the concentration of 0.25, from log 108 to log 105.

L. lactis has antimicrobial and inhibitory properties against the invasion of L. monocytogenes and can be considered an option to inhibit invasion and gastrointestinal infections caused by this bacterium.

Listeria monocytogenes is one of the most important foodborne pathogens that infect various food sources such as raw milk, cheese, ice cream, vegetables, ready-to-eat (RTE) foods, poultry, meat, and fish. Listeria monocytogenes can cause severe diseases such as meningoencephalitis, abortion, and septicemia, with a high mortality rate (30%) in humans. Therefore, the present study was carried out to molecularly investigate the frequency of Listeria monocytogenes in raw milk samples.

In this study, 150 raw milk samples from Zanjan province, Iran, were collected at regular intervals. Pure isolates of Listeria monocytogenes were obtained after enrichment in Buffered Listeria enrichment broth (BLEB), followed by plating onto blood agar and PALCAM agar medium and incubation at 35 °C for 48 hours. A hly gene-based PCR assay was developed to detect the presence or absence of virulence genes in isolated Listeria monocytogenes.

The results showed that only one sample was positive by both real-time and conventional PCR methods. It contained three virulence genes, including hlyA, actA, and prf-A, among the virulence genes studied.

The prevalence of Listeria monocytogenes in Zanjan province was lower than in previous studies, which was attributed to the small number of samples and the sampling season.

Listeriolysin (LLO) is a sulfhydryl-activated hemolysin bound to cholesterol, that is encoded by the hlyA gene of Listeria monocytogenes. The aim of this study was to detect and determine the frequency of Listeria monocytogenes in food samples through molecular analysis of the hlyA gene.

The present study was a descriptive cross-sectional assay conducted from the middle of October 2018 to the end of January of the same year. One hundred sixty-five samples of different types of meat, vegetables, hamburgers and shrimps were examined. Samples were randomly collected from restaurants, delicatessens, prepared food places, and different supermarkets. All samples were analyzed with phenotypic and biochemical tests. The samples suspected of Listeria monocytogenes, after DNA extraction, were evaluated by PCR with specific primers for the hlyA gene. Then the data and results were evaluated with using SPSS v.23 software and Excel software.

Phenotypic methods (microbial culture and biochemical investigation) confirmed 18 positive samples for Listeria monocytogenes, of which 10 (6.06%) samples were positive for Listeria monocytogenes by PCR of the hlyA gene. The rate of contamination in pounded kebab was 37.9%, chicken meat 4.4%, local hamburger 16.66% and lettuce 13.33%. Compared to other studies, these findings were more prevalent in some foods (e.g., local hamburger) and less in others (e.g., chicken meat).

The use of biochemical methods for determining the frequency of Listeria monocytogenes in food samples in Sanandaj had a high percentage of false positives.

The aim of this study was to assess inhibitory effects of thymol and eugenol against Listeria monocytogenes and Escherichia coli O157:H7 as well as assessing ability of chitosan coating containing thymol and eugenol to control Listeria monocytogenes and Escherichia coli O157:H7 inoculated into chicken fillets over a 12-day storage under cold conditions (4 ºC ±1).

Antimicrobial activity of the thymol and eugenol against the bacteria was assessed using microdilution and disk diffusion methods. Chitosan coatings with thymol and eugenol were used to inhibit growth of L. monocytogenes and E. coli O157:H7 cocktails inoculated into chicken fillets during storage for 12 days in refrigerator.

The MIC of thymol against L. monocytogenes and E. coli O157:H7 included 0.3 and 0.6 mg/ml, respectively, and MBC of this compound included 0.6 and 1.25 mg/ml, respectively. The MIC of eugenol against L. monocytogenes and E. coli O157:H7 respectively included 0.6 and1.25 mg/ml and MBC included 1.25 and 2.5 mg/ml, respectively. Assessment of the combined treatments of thymol and eugenol revealed synergistic activities of these compounds against the highlighted bacteria. The average number of bacteria in treated food samples with enriched chitosan coatings of thymol and eugenol and combinations of the two compounds significantly varied (p < 0.05) during 12 days of storage.

Due to the good antimicrobial effects of thymol and eugenol, chitosan coatings enriched with thymol and eugenol and combinations of the two compounds can be used to prevent growth of pathogens on food surfaces, especially chicken meat surfaces, in food industries.

Listeria monocytogenes is a gram-positive and foodborne pathogen that is psychrophilic and has the ability to tolerate a high percentage of salt by more than 10%. This bacterium grows in many food products that have a long shelf life. This study was performed to evaluate the expression of genes hly and inlA of Listeria monocytogenes bacteria in the viable but non-culturable (VBNC) condition in temperatures of 4 degrees Celsius.

In this descriptive laboratory study, bacteria in 106 counts in mid log phase were inoculated into BHI Agar rich medium and It was investigated and stored at refrigerated temperature (4 degrees Celsius) until the cultivate was lost. At the end of the 16S rRNA gene, the hly and inlA genes were studied as pathogenic genes of this bacterium. The expression of these genes before and after entering to VBNC state was performed to compare their expression.

Listeria bacteria lost its cultivation ability after 5 months of storage at a refrigerated temperature. The results of the gene expression analysis showed that at the end of the period, the bacterium entered "Viable But non-Culturable" form; also the hly and inlA pathogenic genes were not expressed in riched medium. By adding blood to the rich culture medium of this bacterium, the hemolysin O pathogen gene was re-illuminated.

The results of this study show that the possibility of bacterial entry into VBNC mode occurs at the refrigerator condition, and the expression of its pathogenic genes is affected. Blood and its agents can act as an agent for the induction and clarification of the hly gene. Therefore, it is necessary to review the microbial quality control of fishery products.

Listeriosis can be fatal for vulnerable groups of society. The disease has been widespread in recent years due to the large consumption of dairy and meat products. There is little information about the susceptibility of antibiotics and the pattern of Listeria monostigenesis gene resistance in Iranian society. Accordingly, the present study was conducted to investigate the antibiotic susceptibility and genetic resistance pattern of Listeria monosteogenesis strains isolated from different clinical and environmental sources.

In this study, 55 isolates were tested for antibiotic susceptibility by disk diffusion in agar and genetic pattern by polymerase chain reaction (PCR).

91% and 83% of the strains were resistant to streptomycin and Trimethoprim/sulfamethoxazole respectively. The result of PCR of antibiotic resistance genes showed that the prevalence of ermA, ermB, strA, tetA, tetS and ermC genes in isolates of Listeria monocytogenes was 50.90% (28/55), 21.81% (12/55), 89.9% (49/55), 0% (0/55), 21.81% (12/55) and 0% (0/55), respectively.

Due to the presence of 1/2a and 1/2c serotypes in isolated isolates and the presence of marker virulence genes in these strains, these isolates have potential for biological risks and listeriosis disease. Existence of this genetic pattern and resistance pattern can be partly due to the use of antibiotics during the production of dairy products. Regarding results of this study, the manner and rate of using animal antibiotics can be managed.

Listeria monocytogenes is a foodborne pathogen and a pothential risk to public health. Listeriosis is one of the most serious infectious diseases in most developed countries. Consumption of raw milk and unpasteurized traditional dairy products such as cheese can be a major reason for listeriosis in humans. This reaserch aimed at investigating Listeria monocytogenes contamination in unpasteurized cheese products by using culture and Polymerase Chain Reaction (PCR) in Qazvin, Iran.

In this research, 128 samples of traditional cheese products were collected from different traditional shopping centers in Qazvin, between October 2017 and September 2018. They were transported to the laboratory under controlled conditions. All isolates were analysed to biochemical test. L. monocytogenes strains were further confirmed by PCR amplification.

Findings showed that 14 samples (10.9%) were contaminated with L. monocytogenes. The highest prevalence of L. monocytogenes was found in white cheese samples (7%). The highest rate of contamination was reported in spring and winter (3.1%).

Listeria contamination in cheese samples studied can pose a serious risk to consumers of non-pasteurized dairy products. Therefore, food safety and health practitioners should apply effective methods and standards.

Due to the human need for food, any change in the quality and quantity of food will affect the health of the community. It is important to remove microbial contaminants from food during the production, storage and supply phases. In this study, the antibacterial effects of nanoparticles of zinc oxide on two Escherichia coli and Listeria monocytogenes were investigated.

In this study, zinc oxide nanoparticles were prepared from zeolite and quantified by X-ray fluorescence. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of nanoparticles of zinc oxide were determined using a disc diffusion method. Graphpad prism statistical software was used for data analysis and ANOVA was used for analysis of variance. Significant limit was set at 0.05 (P≤0.05).

Based on the results of this study, the MIC value of nanoparticles of zinc oxide for all tested bacteria was 4 mg/ml, and the MBC values for standard strain and Escherichia coli isolates were 8 and 4 mg/ml, respectively. The standard strain and isolate of Listeria monocytogenes was calculated to be 4 mg/ml.

The present study showed that zinc oxide nanoparticles can be used as a deterrent against the pathogens of the materials and avoid contamination.

Wastewater treatment plants represent one of the most important approachs for water conservation. On the other hand, wastewaters can act as a source of antibiotics in aquatic environments. The aim of this study was to evaluate the performance of the Yasooj municipal wastewater treatment plant for removal of Escherichia coli, Pseudomonas aeruginosa and Listeria monocytogenes and also the antibiotic resistance pattern of these bacteria. In this cross sectional study, samples of inlet, outlet aerated lagoon, outlet settlement lagoon and outlet effluent were collected from the wastewater treatment plant in order to count, isolate, and identify E. coli, P. aeruginosa and L. monocytogenes. Antibiotic resistance pattern was investigated using disk diffusion method for 6 different antibiotics according to CLSI reference method. E. coli, P. aeruginosa and L. monocytogenes were isolated and identified in all levels of purification of wastewater treatment plants. The effectiveness of sewage treatment processes to remove E. coli, P. aeruginosa and L. monocytogenes was 54.17-99.33 in the outlet effluent. The bacterial isolates showed high rate of resistance against cefixime and trimethoprim-sulfamethoxazole and low resistance to imipenem. Multidrug resistance pattern (double and triple) was observed in bacterial isolates. This study showed that antibiotic-resistant bacteria in the outlet effluent are discharged into the environment. Further research needs to be undertaken to improve sewage treatment technologies, thereby producing a better quality treated sewage effluent.

Genus Listeria especially Listeria monocytogenes (L.monocytogenes), as a food-borne pathogen, is the causative agent of Listeriosis that could be fatal in high risk subjects such as pregnant women, immunocompromised persons, neonates, and elderly. In the present study, the frequency of Listeria spp. and L.monocytogenes in 277 food and environmental samples from retail food markets of Urmia city was evaluated. After isolation and identification of strains, their antimicrobial resistance to 8 antibiotics of isolates was investigated by Kirby – bauer method. Out of 277 samples, 10 (3.61%) were positive for presence of Listeria spp. based on the polymerase chain reaction (PCR). Of 10 isolates, 3 (1.08%) isolates were identified as L.monocytogenes and molecular confirmation was done by PCR for plc-A gene. The frequencies of other species were L.ivanovii (0.72%), L.siligerii (0.72%) and 0.36% for welchimeri, grayi and innocua species, respectively (. Eight of the isolates (80%) were resistant to ampicillin and 7 (70%) to penicillin G. Their resistance to Co-trimoxazole and Gentamicin was not seen among isolates. Besides that, the resistance rate to erythromycin, rifampin, and tetracycline was 20%, for each antibiotic. The result of present study indicated the resistance of Listeria species isolated from food against antibacterial agents that are therapeutic choice for Listeriosis. This reveals the prompt need for surveillance program and information system setup about listeria in Iran.

Listeria monocytogenes is an important food-borne intracellular pathogen which can transmit to human through contaminated foods and causing meningitis, meningoencephalitis and abortion. This study was done to determine the frequency, antimicrobial susceptibility and serotyping of Listeria monocytogenes isolated from food samples in Tehran, Iran. This descriptive was carried on 150 food samples including vegetables, cheese and meat were collected from supermarkets, open-air markets, and delicatessens in different regions of Tehran, Iran since April to September 2018. The presumptive isolates were characterized biochemically. All L. monocytogenes isolates were further analyzed by serotyping and antimicrobial susceptibility tests. Out of 150 samples, Listeria spp. was detected in 30 (20%) samples in which 9 (6%) were positive for L. monocytogenes [vegetables (n=4, 44.44%), cheese (n=2, 22.22%) and meat (n=3, 33.33%)]. of the 9 L. monocytogenes isolates, 5 (55.55 %), 3 (33.33 %), and 1 (11.11%) belonged to serotypes 4b, 1/2b, and 1/2a, respectively. The most L. monocytogenes isolates were resistant to Trimetoprime, Sulfamethoxazole, Tetracycline, Streptomycin, Chloramphenicol, and Ciprofloxacin while were sensitive to Penicillin G, Gentamicin, Streptomycin, and Ampicillin, and were intermediately resistant to Ciprofloxacin. The rate of Contamination of vegetable, cheese and meat samples with L. monocytogenes is important in Tehran, Iran. Due to the potential contamination samples to Listeria, there is necessity need for continuous monitoring and the development of a precise program for identifying this bacterium in Tehran and the whole country.

Abortion is one of the most important medical problems which imposes a high cost on the households. Listeria monocytogenes is one of the most important causes of abortion and postpartum infection in the newborns. The aim of this study was to determine the prevalence of Listeria monocytogenes in the pregnant women and compare its prevalence rates between women with and without a history of abortion in Tehran and also prevalence of hlyA virulence gene.

In this cross sectional study, from May 2016 to December 2016 clinical samples of vaginal discharge were taken from pregnant women with and without a history of abortion. All of the samples (100 sample) were collected from the patients referring to Arash Hospital in Tehran, by a gynecologist. The women filled out a questionnaire. The pregnant women who had received antibiotic were excluded from the study. All samples were transferred to the microbiological lab, rapidly.

After culture and differential tests, among 100 sample we isolated Listeria from 7 % (7 strains) of the samples (4 strains of L .monocytogenesis and 3 strains of Listeria seeligeri).
In the samples taken from pregnant women with a history of abortion we found 3 stains of L.monocytogenes and one strain of Listeria seeligeri. In the samples obtained from pregnant women without a history of abortion one stains of L .monocytogenes and 2 strains of Listeria seeligeri were detected.

The results of this study showed that the prevalence of Listeria monocytogenes in the pregnant women with a history of abortion is more than that in the pregnant women without a history of abortion.
Despite the fact that this bacterium was not confirmed as a major cause of abortion in our study, but it may expose pregnant women to the risk of this problem

Listeria monocytogenes is an important psychrotrophic foodborne pathogen that exists in poultry meat and causes listeriosis with severe clinical consequences such as meningitis, septicemia, and abortion. Therefore, contamination of food stuff implies a significant health risk for human. Data on contamination of poultry meat and poultry slaughterhouse with Listeria monocytogenes are scarce in Iran. Thus, the objective of this study was to assess the prevalence of antibiotic resistance and Listeria monocytogenes in poultry meat and poultry slaughterhouse environment in the city of Yazd.
To determine the presence of L.monocytogenes culture media and biochemical tests were used; then, isolates were confirmed by Polymerase Chain Reaction (PCR). At the end, the antibiogram test was conducted to determine antibiotic resistance.
A total of 811 samples selected from the two slaughter houses were analyzed; from which 104 samples (12.8%) were contaminated with Listeria monocytogenes. The highest amount of contamination was observed in Swap the Cold storage surfaces , while the lowest levels of contamination were related to chicken carcass before chiller. The highest amount of antibiotic resistance was for ampicillin, tetracycline, and penicillin.
The results of this study indicate contamination of chicken meat and antibiotic resistance of isolated Listeria monocytogenes. Since chicken meat is highly consumed and is transferred in raw form, also due to lack of proper control and use of antibiotics during breeding, it can lead to serious health risks in the community. Lack of knowledge about risks of listeriosis indicates the need for implementing food safety education programs. In addition, the Iranian food safety authorities should urgently set up an effective standard to screen all susceptible foods for the presence of Listeria.

The bacterium causes listeriosis with severe clinical consequences such as meningitis, septicemia and abortion. There are a minimum data on dairy products contamination of Listeria in Iran. Thus, the objective of this study was to assess the prevalence of Listeria monocytogenes in traditional ice cream in Yazd, Iran and to summarize the studies that reported Listeria monocytogenes contamination in traditional dairy and if possible conduct metaanalyses to report single estimates for raw milk and ice cream for the whole country.
A total of 85 samples of traditional ice cream were examined for the presence of Listeria monocytogenes using a two-step selective enrichment. All isolates were subjected to standard biochemical test. We searched PubMed, science direct, Scopus, Google Scholar and Iranian local databases including Iranian Scientific Information database (www.sid.ir), Magiran (www.magiran.com) using the following keywords: prevalence, Listeria monocytogenes, raw milk, ice cream and Iran. Twenty-six items of related articles on raw milk and ice cream were conducted of different cities. Studies were included in the meta-analysis. Statistical heterogeneity between studies was evaluated using Cochran's Q test and I-squared. All Statistical analyses were conducted using STATA version 11.2.
On the basis of biological tests, none of the samples were contaminated with Listeria monocytogenes. The results of the meta-analysis showed that the prevalence of L. monocytogenes in raw milk 4% and 7.1% traditional ice cream. P values less than0.05 were considered statistically significant.
Consumption of raw milk with mild heat treatment or its usage in traditional dairy a common practice in Iran. Therefore, the lack of appropriate control measures could pose serious health problems.

Organic acids (e.g. acetic and lactic acid) have been used in foods as natural preservatives. Acetic acid and its salts are used in foods as antimicrobial and acidulant agents. The aim of this study was to evaluate the antibacterial activity of acetic and lactic acids against the Listeria monocytogenes.
This experimental study was conducted at the Department of Food Hygiene (Faculty of Veterinary Medicine, Urmia University) during autumn 2015. The antibacterial effects of acetic and lactic acid against Listeria monocytogenes were determined using minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and cell constituents release methods. The concentration ranges of acetic and lactic acid (0.0195-10 and 0.043-22.2 μl/ml, respectively) were used to determine the MIC of acids.
Based on the results, acetic and lactic acid inhibited the growth of Listeria monocytogenes and acetic acid had stronger effect against the the bacterium. The MIC values for acetic acid and lactic acid were 2.5 and 5 μl/ml, respectively. Cell constituents release showed that acetic and lactic acids are able to lyze the bacterial cell.
Acetic and lactic acids were effective in inhibiting the growth of Listeria monocytogenes and the antibacterial effect of acetic acid was stronger than that lactic acid. These acids can be used in foods in combination with other preservatives to inhibit the food borne pathogens and food spoilage microorganisms.

The ubiquitous nature of Listeria monocytogenes and its ability to grow at refrigerated temperature makes L. monocytogenes a serious threat to the safety of ready-to-eat (RTE) meat products. Lactic acid bacteria (LAB) have been found to be effective in inhibiting L. monocytogenes in food products such as fresh and cooked meats. Prebiotics exist in many foodstuffs such as garlic which stimulates the growth of lactobacilli. The aim of this study was to use Lactobacillus reuteri together with aqueous extract of garlic for controlling the growth of Listeria monocytogenes.
First stimulatory effect of water extract of garlic in different concentrations (50, 100 and 200 mg/ml) on the growth of L. reuteri was evaluated. Then, inhibitory effect of L. reuteri along with aqueous extract of garlic against Listeria monocytogenes was investigated for 0, 4, 8 and 24 h.
The results of this study showed that two concentration (100 and 200 mg/ml) of aqueous extracts of garlic had highest stimulatory effect on Lactobacillus reuteri growth. Also L. ruteri along with garlic extract significantly inhibited the growth of listeria monocytogenes.
The application of garlic extract along with lactobacillus ruteri may increase the inhibitory effect of lactobacillus against listeria monocytogenes.

Background and Recently, natural antimicrobials attracted a lot of attention due to increasing preference of consumers for organic products which are free of chemical additives. The aim of this study was to investigate the antibacterial activity of cinnamaldehyde in combination with acetic and lactic acids against L.monocytogenes.
The antibacterial effects of cinnamaldehyde, acetic and lactic acids were determined using minimum inhibitory concentration (MIC). Fractional inhibitory concentration (FIC) was also used to evaluate the combined antibacterial activity.
Based on our results, MIC values for cinnamaldehyde, acetic acid and lactic acid were 0.312, 2.5 and 5 μl/ml, respectively. FIC results showed that cinnamaldehyde combination with the organic acids had no interaction effects (1.0 Cinnamaldehyde, acetic and lactic acids were found effective in inhibiting the growth of L. monocytogenes. Meanwhile, organic acids can reduce the required amount of cinnamaldehyde.

Increasing consumption of ready to eat foods which usually receive low heating process can cause the emergence of microbial hazards. Listeria monocytogenes is one of the most dangerous foodborne bacteria which can result in disease and death in old, pregnant and immunosuppressed individuals. Lactobacilli are naturally present in most foods. Since ancient times, they were regarded as natural preservatives in food. The aim of this study was to evaluate the biochemical and molecular characterization of Lactobacillus isolates and investigate their antibacterial effects on Listeria monocytogenes
Sixty five meat samples were obtained from slaughter house in Urmia city. First, isolated bacteria were evaluated using phenotypic methods (morphology, Gram stain and catalase test). Then, polymerase chain reaction (PCR) and sugar fermentation tests were used. Finally, their antibacterial properties against Listeria monocytogenes were tested by two methods (agar wells diffusion and spot on plate).
Six strains of lactobacilli were identified using PCR. The antibacterial tests showed moderate effects of lactobacilli on Listeria monocytogenes growth.
The results indicated that lacobacilli can be used as a biocontrol agent to inhibit of Listeria monocytogenes growth.