scholarly journals Evaluation of Multiplex PCR System for Simultaneous Detection of Escherichia coli O157:H7, Listeria monocytogenes and Salmonella enteritidis in Shrimp Samples

1970 ◽  
Vol 24 (1) ◽  
pp. 42-46 ◽  
Author(s):  
Mahmuda Yasmin ◽  
Susumu Kawasaki ◽  
Shinichi Kawamoto

A multiplex polymerase chain reaction (PCR) method was evaluated for simultaneous detection of Escherichia coli O157:H7, Listeria monocytogenes and Salmonella enteritidis in shrimp samples. The sensitivity of DNA amplification by PCR in this method was found to be 103 cfu/ml for each pathogen. When this protocol was adopted for the detection of each of the above mentioned pathogen in spiked shrimp extract culture, similar sensitivity was observed. However, this method detected 1 bacterial cell for E. coli O157:H7 and S. enteritidis and 100 for L. monocytogenes per 25 g spiked shrimp samples after overnight enrichment. In the commercially imported shrimp samples, none was found to contain any of the three pathogens by multiplex PCR or by conventional method, which suggests that the multiplex PCR is a reliable and useful for rapid screening of shrimp samples for E. coli O157:H7, L. monocytogenes and S. enteritidis. This will save time and increase our ability to assure food safety. Keywords: Multiples PCR, Shrimp extract, Spiked sample, Escherichia coli O157:H7, Listeria monocytogenes, Salmonella enteritidisDOI: http://dx.doi.org/10.3329/bjm.v24i1.1236 Bangladesh J Microbiol, Volume 24, Number 1, June 2007, pp 42-46

2005 ◽  
Vol 68 (3) ◽  
pp. 551-556 ◽  
Author(s):  
SUSUMU KAWASAKI ◽  
NAOKO HORIKOSHI ◽  
YUKIO OKADA ◽  
KAZUKO TAKESHITA ◽  
TAKASHI SAMESHIMA ◽  
...  

A multiplex PCR method was developed for simultaneous detection of Salmonella spp., Listeria monocytogenes, and Escherichia coli O157:H7 in meat samples. DNA detection sensitivity for this method was 103 CFU/ml for each pathogen. When this protocol was used for the detection of each of the above pathogenic bacteria in spiked pork samples, 1 cell per 25 g of inoculated sample could be detected within 30 h. In the samples of naturally contaminated meat, Salmonella spp., L. monocytogenes, and E. coli O157:H7 were detected over the same time period. Excellent agreement was obtained for the results of multiplex PCR and the conventional culture method, which suggests that the multiplex PCR is a reliable and useful method for rapid screening of meat products for Salmonella spp., L. monocytogenes, and E. coli O157:H7 contamination.


2002 ◽  
Vol 65 (8) ◽  
pp. 1215-1220 ◽  
Author(s):  
CHIA-MIN LIN ◽  
SARAH S. MOON ◽  
MICHAEL P. DOYLE ◽  
KAY H. McWATTERS

Iceberg lettuce is a major component in vegetable salad and has been associated with many outbreaks of foodborne illnesses. In this study, several combinations of lactic acid and hydrogen peroxide were tested to obtain effective antibacterial activity without adverse effects on sensory characteristics. A five-strain mixture of Escherichia coli O157:H7, Salmonella enterica serotype Enteritidis, and Listeria monocytogenes was inoculated separately onto fresh-cut lettuce leaves, which were later treated with 1.5% lactic acid plus 1.5% hydrogen peroxide (H2O2) at 40°C for 15 min, 1.5% lactic acid plus 2% H2O2 at 22°C for 5 min, and 2% H2O2 at 50°C for 60 or 90 s. Control lettuce leaves were treated with deionized water under the same conditions. A 4-log reduction was obtained for lettuce treated with the combinations of lactic acid and H2O2 for E. coli O157:H7 and Salmonella Enteritidis, and a 3-log reduction was obtained for L. monocytogenes. However, the sensory characteristics of lettuce were compromised by these treatments. The treatment of lettuce leaves with 2% H2O2 at 50°C was effective not only in reducing pathogenic bacteria but also in maintaining good sensory quality for up to 15 days. A ≤4-log reduction of E. coli O157:H7 and Salmonella Enteritidis was achieved with the 2% H2O2 treatment, whereas a 3-log reduction of L. monocytogenes was obtained. There was no significant difference (P > 0.05) between pathogen population reductions obtained with 2% H2O2 with 60- and 90-s exposure times. Hydrogen peroxide residue was undetectable (the minimum level of sensitivity was 2 ppm) on lettuce surfaces after the treated lettuce was rinsed with cold water and centrifuged with a salad spinner. Hence, the treatment of lettuce with 2% H2O2 at 50°C for 60 s is effective in initially reducing substantial populations of foodborne pathogens and maintaining high product quality.


2020 ◽  
Vol 12 (2) ◽  
pp. 212-217 ◽  
Author(s):  
Juan Du ◽  
Shujing Wu ◽  
Liyuan Niu ◽  
Junguang Li ◽  
Dianbo Zhao ◽  
...  

Unfunctionalized flower-shaped AuNPs is used as colorimetric sensor for PCR product detection by naked eyes.


2004 ◽  
Vol 67 (8) ◽  
pp. 1634-1640 ◽  
Author(s):  
GI-SEONG MOON ◽  
WANG JUNE KIM ◽  
WEON-SUN SHIN

For rapid detection of Escherichia coli O157:H7 and Listeria monocytogenes, simple methods for sample preparation and PCR were established and applied to a field test. To improve specificity, primer sets LP43-LP44 and C(+)-D(−) were selected for E. coli O157:H7 and L. monocytogenes, respectively. Through centrifugation and partial heat treatment after enrichment,E. coli O157:H7 and L. monocytogenes were detected at 1 initial CFU without genomic DNA extraction in the culture and with artificially inoculated food samples including milk, chicken, ham, and pork. Based on the optimized PCR method, a feasibility test was carried out using randomly collected field samples. To remove false positives and false negatives, a PCR method using several primer sets, including the optimized primer set, and a standard culture method were used. With the PCR detection and standard culture methods, two pork samples were positive for L. monocytogenes after enrichment, indications that the PCR assay could be effectively used for rapid, sensitive, and species-specific detection of foodborne pathogens.


2004 ◽  
Vol 67 (7) ◽  
pp. 1497-1500 ◽  
Author(s):  
Y. INATSU ◽  
M. L. BARI ◽  
S. KAWASAKI ◽  
K. ISSHIKI

The survival of gram-positive and gram-negative foodborne pathogens in both commercial and laboratory-prepared kimchi (a traditional fermented food widely consumed in Japan) was investigated. It was found that Escherichia coli O157:H7, Salmonella Enteritidis, Staphylococcus aureus, and Listeria monocytogenes could survive in both commercial and laboratory-prepared kimchi inoculated with these pathogens and incubated at 10°C for 7 days. However, when incubation was prolonged, the S. aureus level decreased rapidly from the initial inoculum level to the minimum detectable level within 12 days, whereas Salmonella Enteritidis and L. monocytogenes took 16 days to reach similar levels in commercial kimchi. On the other hand, E. coli O157:H7 remained at high levels throughout the incubation period. For laboratory-prepared kimchi, the S. aureus level decreased rapidly from the initial inoculum level to the minimum detectable level within 12 days, and L. monocytogenes took 20 days to reach a similar level. E. coli O157:H7 and Salmonella Enteritidis remained at high levels throughout the incubation period. The results of this study suggest that the contamination of kimchi with E. coli O157:H7, Salmonella Enteritidis, S. aureus, or L. monocytogenes at any stage of production or marketing could pose a potential risk.


1999 ◽  
Vol 65 (9) ◽  
pp. 4276-4279 ◽  
Author(s):  
Kumar S. Venkitanarayanan ◽  
Gabriel O. Ezeike ◽  
Yen-Con Hung ◽  
Michael P. Doyle

ABSTRACT The efficacy of electrolyzed oxidizing water for inactivatingEscherichia coli O157:H7, Salmonella enteritidis, and Listeria monocytogenes was evaluated. A five-strain mixture of E. coli O157:H7,S. enteritidis, or L. monocytogenes of approximately 108 CFU/ml was inoculated in 9 ml of electrolyzed oxidizing water (treatment) or 9 ml of sterile, deionized water (control) and incubated at 4 or 23°C for 0, 5, 10, and 15 min; at 35°C for 0, 2, 4, and 6 min; or at 45°C for 0, 1, 3, and 5 min. The surviving population of each pathogen at each sampling time was determined on tryptic soy agar. At 4 or 23°C, an exposure time of 5 min reduced the populations of all three pathogens in the treatment samples by approximately 7 log CFU/ml, with complete inactivation by 10 min of exposure. A reduction of ≥7 log CFU/ml in the levels of the three pathogens occurred in the treatment samples incubated for 1 min at 45°C or for 2 min at 35°C. The bacterial counts of all three pathogens in control samples remained the same throughout the incubation at all four temperatures. Results indicate that electrolyzed oxidizing water may be a useful disinfectant, but appropriate applications need to be validated.


2002 ◽  
Vol 65 (1) ◽  
pp. 100-105 ◽  
Author(s):  
KUMAR S. VENKITANARAYANAN ◽  
CHIA-MIN LIN ◽  
HANNALORE BAILEY ◽  
MICHAEL P. DOYLE

The objective of this study was to develop a practical and effective method for inactivating or substantially reducing Escherichia coli O157:H7, Salmonella Enteritidis, and Listeria monocytogenes on apples, oranges, and tomatoes. Apples, oranges, and tomatoes were spot-inoculated with five-strain mixtures of E. coli O157:H7, Salmonella Enteritidis, and L. monocytogenes near the stem end and were submerged in sterile deionized water containing 1.5% lactic acid plus 1.5% hydrogen peroxide for 15 min at 40°C. Inoculated samples treated with sterile deionized water at the same temperature and for the same duration served as controls. The bacterial pathogens on fruits subjected to the chemical treatment were reduced by >5.0 log10 CFU per fruit, whereas washing in deionized water decreased the pathogens by only 1.5 to 2.0 log10 CFU per fruit. Furthermore, substantial populations of the pathogens survived in the control wash water, whereas no E. coli O157:H7, Salmonella Enteritidis, or L. monocytogenes cells were detected in the chemical treatment solution. The sensory and qualitative characteristics of apples treated with the chemical wash solution were not adversely affected by the treatment. It was found that the treatment developed in this study could effectively be used to kill E. coli O157:H7, Salmonella Enteritidis, and L. monocytogenes on apples, oranges, and tomatoes at the processing or packaging level.


2019 ◽  
Vol 24 (1) ◽  
pp. 277-294
Author(s):  
Rocio Esperanza Patiño-Burbano ◽  
Ana Karina Carrascal ◽  
Jorge Luis Parra-Arango ◽  
José Luis Rodríguez-Bautista

Raw cow milk is considered one of the most important vehicles for pathogenic bacteria like Salmonella spp., Escherichia coli O157:H7, and Listeria monocytogenes. These three bacteria are responsible for foodborne diseases. Routine microbiological methods to detect these microorganisms in cow milk can be complicated and time consuming. The aim of this work was to evaluate a method to simultaneously detect Salmonella spp., Escherichia coli O157:H7, and Listeria monocytogenes in experimentally contaminated cow milk. The assessed method combined a standard microbiological culture step, using a pre-enrichment medium that favors the growth of the three focal microorganisms: SEL broth, followed by a single PCR assay. A total of 43 interference bacterial strains were used to evaluate the method’s specificity. The detection rate for the microbiological method with standard culture media was 10 UFC/mL, and that of the PCR detection, following pre-enrichment in SEL broth, was 10 UFC/mL for S. enterica and L. monocytogenes and between 1 and 5 UFC/mL for E. coli O157:H7. The PCR method showed specificity for the reference strains. Simultaneous detection by multiple PCR using SEL broth was successful for the detection of S. enterica, E. coli O157:H7, and L. monocytogenes in samples of experimentally contaminated cow milk, featuring both a high detection rate and a high specificity. This approach promises to be a feasible routine procedure when testing milk samples in industry and public health control setups.


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