scholarly journals A newly developed polydopamine-coated paper-based microchip for rapid and highly selectivity detection of foodborne pathogens

2021 ◽  
Author(s):  
Jinfeng Liu ◽  
Mimi Zhang ◽  
Zhiqiang Shen ◽  
Yongxin Liu ◽  
Yang Song ◽  
...  
Keyword(s):  
Foodborne Pathogens ◽  
Pathogen Detection ◽  
Lower Cost ◽  
Limit Of Detection ◽  
Fluorescence Labeling ◽  
Economic Losses ◽  
Great Promise ◽  
Salmonella Spp ◽  
Coated Paper ◽  
E Coli

Abstract Background In 2020, Covid-19 pneumonia has had a great impact on human health in although the countries around the world, it brings serious threaten to people’s lives and resulted in serious economic losses. At the same time, a lot news about the detection of Covid-19 in food emerges endlessly, a rapid and high selectivity detection method or technology is in urgent need for its ability to help relevant departments effectively control the epidemic situation and ensuring people’s lives and property safety. In recent years, loop-mediated isothermal amplification (LAMP) has been certified as a quick and highly selective technique to detect foodborne microorganisms. Results In this paper, a newly developed microchip with polydopamine-coated paper based on LAMP was fabricated. This microchip consists of nine chambers for sampling and reactions, the targeted nucleic acid of foodborne pathogens was labeled by calcein fluorescence rather than SYBR. The microchip is advantageous of lower cost of materials and simple pretreated methods, and is easy to operate without the need for complex controlled fluid flow. The LAMP procedure and fluorescence detection of pathogens can be carried on the chip without opening the lid, preventing aerosol contamination and reducing the probability of false positives. In experiments, the LAMP reaction conditions including the optimal reaction temperature and reaction time are thoroughly discussed and have been executed for various foodborne bacteria samples, including Escherichia coli O157:H7 (E. coli O157:H7), Salmonella spp., Staphylococcus aureus (S. aureus), and Vibrio parahaemolyticus (V. parahaemolyticus). Testing of E. coli O157:H7 proved to be highly selective and sensitive (as low as 0.0134 ng µL− 1). Additionally, experimental test of real milk sample was figured, the complete detection duration time was within 68 min, the limit of detection(LOD) for Salmonella spp. was determined to be lower than 12 CFU mL− 1. Conclusion In summary, a newly developed LAMP microchip with polydopamine-coated and calcein fluorescence labeling paper-based provides a lower cost, easy to use, highly selective, and multiplexable pathogen detection capability with great promise as a rapid, highly efficient, and economical solution for future foodborne pathogen testing.

Changes in Aerobic Plate and Escherichia coli–Coliform Counts and in Populations of Inoculated Foodborne Pathogens on Inshell Walnuts during Storage

2016 ◽  
Vol 79 (7) ◽  
pp. 1143-1153 ◽  
Author(s):  
JOHN C. FRELKA ◽  
GORDON R. DAVIDSON ◽  
LINDA J. HARRIS
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Relative Humidity ◽  
Low Temperature ◽  
Foodborne Pathogens ◽  
Limit Of Detection ◽  
Sampling Time ◽  
E Coli ◽  
Plate Counts ◽  
Forced Air

ABSTRACT After harvest, inshell walnuts are dried using low-temperature forced air and are then stored in bins or silos for up to 1 year. To better understand the survival of bacteria on inshell walnuts, aerobic plate counts (APCs) and Escherichia coli–coliform counts (ECCs) were evaluated during commercial storage (10 to 12°C and 63 to 65% relative humidity) over 9 months. APCs decreased by 1.4 to 2.0 log CFU per nut during the first 5 months of storage, and ECCs decreased by 1.3 to 2.2 log CFU per nut in the first month of storage. Through the remaining 4 to 8 months of storage, APCs and ECCs remained unchanged (P > 0.05) or decreased by <0.15 log CFU per nut per month. Similar trends were observed on kernels extracted from the inshell walnuts. APCs and ECCs were consistently and often significantly higher on kernels extracted from visibly broken inshell walnuts than on kernels extracted from visibly intact inshell walnuts. Parameters measured in this study were used to determine the survival of five-strain cocktails of E. coli O157:H7, Listeria monocytogenes, and Salmonella inoculated onto freshly hulled inshell walnuts (~8 log CFU/g) after simulated commercial drying (10 to 12 h; 40°C) and simulated commercial storage (12 months at 10°C and 65% relative humidity). Populations declined by 2.86, 5.01, and 4.40 log CFU per nut for E. coli O157:H7, L. monocytogenes, and Salmonella, respectively, after drying and during the first 8 days of storage. Salmonella populations changed at a rate of −0.33 log CFU per nut per month between days 8 and 360, to final levels of 2.83 ± 0.79 log CFU per nut. E. coli and L. monocytogenes populations changed by −0.17 log CFU per nut per month and −0.26 log CFU per nut per month between days 8 and 360, respectively. For some samples, E. coli or L. monocytogenes populations were below the limit of detection by plating (0.60 log CFU per nut) by day 183 or 148, respectively; at least one of the six samples was positive at each subsequent sampling time by either plating or by enrichment.

scholarly journals Investigation of the Genes Involved in the Outbreaks of Escherichia coli and Salmonella spp. in the United States

Antibiotics ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1274
Author(s):  
Michelle Li ◽  
Kyle Wang ◽  
Ashley Tang ◽  
Aaron Tang ◽  
Andrew Chen ◽  
...  
Keyword(s):  
Stress Response ◽  
Antimicrobial Resistance ◽  
Pathogen Detection ◽  
Dimensional Space ◽  
Virulence Gene ◽  
Principal Component ◽  
The United States ◽  
Salmonella Spp ◽  
E Coli ◽  
Antimicrobial Resistance Genes

Salmonella spp. and Escherichiacoli (E. coli) are two of the deadliest foodborne pathogens in the US. Genes involved in antimicrobial resistance, virulence, and stress response, enable these pathogens to increase their pathogenicity. This study aims to examine the genes detected in both outbreak and non-outbreak Salmonella spp. and E. coli by analyzing the data from the National Centre for Biotechnology Information (NCBI) Pathogen Detection Isolates Browser database. A multivariate statistical analysis was conducted on the genes detected in isolates of outbreak Salmonella spp., non-outbreak Salmonella spp., outbreak E. coli, and non-outbreak E. coli. The genes from the data were projected onto a two-dimensional space through principal component analysis. Hierarchical clustering was then used to quantify the relationship between the genes in the dataset. Most of the outlier genes identified in E. coli isolates are virulence genes, while outlier genes identified in Salmonella spp. are mainly involved in stress response. Gene epeA, which encodes a high-molecular-weight serine protease autotransporter of Enterobacteriaceae (SPATE) protein, along with subA and subB that encode cytotoxic activity, may contribute to the pathogenesis of outbreak E. coli. The iro operon and ars operon may play a role in the ecological success of the epidemic clones of Salmonella spp. Concurrent relationships between esp and ter operons in E. coli and pco and sil operons in Salmonella spp. are found. Stress-response genes (asr, golT, golS), virulence gene (sinH), and antimicrobial resistance genes (mdsA and mdsB) in Salmonella spp. also show a concurrent relationship. All these findings provide helpful information for experiment design to combat outbreaks of E. coli and Salmonella spp.

Low Prevalence of Salmonella and Shiga Toxin–Producing Escherichia coli in Lymph Nodes of Australian Beef Cattle

2017 ◽  
Vol 80 (12) ◽  
pp. 2105-2111 ◽  
Author(s):  
Gavin Bailey ◽  
Long Huynh ◽  
Lachlan Govenlock ◽  
David Jordan ◽  
Ian Jenson
Keyword(s):  
Escherichia Coli ◽  
Lymph Nodes ◽  
Shiga Toxin ◽  
Limit Of Detection ◽  
Ground Beef ◽  
Plate Count ◽  
Salmonella Spp ◽  
Live Animal ◽  
E Coli ◽  
Low Prevalence

ABSTRACT Salmonella contamination of ground beef has been viewed as originating from the surface of carcasses. Recent studies have identified lymph nodes as a potential source of Salmonella contamination because these tissues play an active role in containment of pathogens in the live animal and because some lymph nodes are unavoidably present in manufacturing beef trimmings or primal cuts that may be incorporated into ground beef. A survey was conducted of the microbiological status of lymph nodes from Australian cattle at the time of slaughter to determine the prevalence of microbiological contamination. Sets of lymph nodes (n = 197), consisting of the superficial cervical (prescapular), prepectoral, axillary, presternal, popliteal, ischiatic, subiliac (precrural), coxalis, and iliofemoralis (deep inguinal), were collected from five geographically separated Australian abattoirs over a period of 14 months. Samples were tested for the presence of Salmonella spp. and Shiga toxin–producing Escherichia coli by BAX PCR assay. Aerobic plate count, E. coli, and coliforms were enumerated with a lower limit of detection of 80 CFU per node. The observed prevalence of Salmonella within peripheral lymph nodes was 0.48% (7 of 1,464). Two of the seven lymph nodes in which Salmonella organisms were detected came from the same animal. Grass-fed, grain-fed, and cull dairy cattle were all found to have detectable Salmonella in lymph nodes. All Salmonella detections occurred during cooler months of the year. No Shiga toxin–producing E. coli were detected. Aerobic microorganisms were detected above the limit of quantification in 3.2% of nodes (median count 2.24 log per node), and E. coli was detected in 0.8% of nodes (median count 3.05 log per node). The low prevalence of Salmonella and low concentration of aerobic microorganisms in Salmonella-positive lymph nodes of Australian cattle at the time of slaughter suggest that the likelihood of lymph nodes contributing significantly to the presence of Salmonella in ground beef is low.

scholarly journals Multiplex Detection of Salmonella spp., E. coli O157 and L. monocytogenes by qPCR Melt Curve Analysis in Spiked Infant Formula

2020 ◽  
Vol 8 (9) ◽  
pp. 1359
Author(s):  
Sarah Azinheiro ◽  
Joana Carvalho ◽  
Marta Prado ◽  
Alejandro Garrido-Maestu
Keyword(s):  
Food Industry ◽  
High Resolution Melting ◽  
Limit Of Detection ◽  
Food Poisoning ◽  
Relative Sensitivity ◽  
Multiplex Detection ◽  
Salmonella Spp ◽  
Melt Curve Analysis ◽  
E Coli ◽  
Reaction Inhibition

Food poisoning continue to be a threat in the food industry showing a need to improve the detection of the pathogen responsible for the hospitalization cases and death. DNA-based techniques represent a real advantage and allow the detection of several targets at the same time, reducing cost and time of analysis. The development of new methodology using SYBR Green qPCR for the detection of L. monocytogenes, Salmonella spp. and E. coli O157 simultaneously was developed and a non-competitive internal amplification control (NC-IAC) was implemented to detect reaction inhibition. The formulation and supplementation of the enrichment medium was also optimized to allow the growth of all pathogens. The limit of detection (LoD) 95% obtained was <1 CFU/25 g for E. coli O157, and 2 CFU/25 g for Salmonella spp. and L. monocytogenes and regarding the multiplex detection a LoD 95% of 1.7 CFU/25 g was observed. The specificity, relative sensitivity and accuracy of full methodology were 100% and the use of the NC-IAC allowed the reliability of the results without interfering with the sensitivity of the methodology. The described study proved to obtain results comparable to those of probe-based qPCR, and more economically than classical high resolution melting qPCR, being both important aspects for its implementation in the food industry.

A STUDY OF CROSS-CONTAMINATION OF FOODBORNE PATHOGENS ON THE KITCHEN SURFACES

2015 ◽  
Vol 77 (31) ◽  
Author(s):  
Murni Noor Al Amin ◽  
Wan Rosmiza Zana Wan Dagang
Keyword(s):  
Foodborne Pathogens ◽  
Cross Contamination ◽  
Salmonella Spp ◽  
Isolation And Identification ◽  
E Coli ◽  
Meal Preparation ◽  
Before And After ◽  
Change In The Mean ◽  
Plate Counts ◽  
Raw Poultry

Cross-contamination provides the opportunity for various of bacteria to be deposited on each of the surface contact during meal preparation. Raw poultry especially raw chicken was the main reservoir of foodborne pathogens that can cause foodborne diseases. Therefore, a study on the potential of cross-contamination contribute to spread E. coli, Salmonella spp. and S. aureus on the kitchen surfaces during chicken preparation was conducted. A total of 36 isolates were collected from six sampling sites before and after the chicken preparation. The enumeration of the bacteria from the sampling sites showed a significant change in the mean total plate counts (TPC) of the isolates before and after the chicken preparation. These results emphasized that cross-contamination occurred around the sampling sites during the preparation of the chicken. Isolation and identification of the three foodborne pathogens, E. coli, Salmonella spp. and S. aureus were carried out on its respectively selective and differential media. The presumptive identified foodborne pathogens were confirmed as E. coli, Salmonella spp. and S. aureus according to their microscopic and biochemical characteristics.

scholarly journals Recent Progress on the Electrochemical Biosensing of Escherichia coli O157:H7: Material and Methods Overview

Biosensors ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 54 ◽  
Author(s):  
Nasrin Razmi ◽  
Mohammad Hasanzadeh ◽  
Magnus Willander ◽  
Omer Nur
Keyword(s):  
Escherichia Coli ◽  
Pathogen Detection ◽  
Recent Progress ◽  
Electrochemical Sensors ◽  
Solid Phase ◽  
Great Promise ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Electrochemical Biosensing ◽  
Sensitivity And Selectivity

Escherichia coli O157:H7 (E. coli O157:H7) is a pathogenic strain of Escherichia coli which has issued as a public health threat because of fatal contamination of food and water. Therefore, accurate detection of pathogenic E. coli is important in environmental and food quality monitoring. In spite of their advantages and high acceptance, culture-based methods, enzyme-linked immunosorbent assays (ELISAs), polymerase chain reaction (PCR), flow cytometry, ATP bioluminescence, and solid-phase cytometry have various drawbacks, including being time-consuming, requiring trained technicians and/or specific equipment, and producing biological waste. Therefore, there is necessity for affordable, rapid, and simple approaches. Electrochemical biosensors have shown great promise for rapid food- and water-borne pathogen detection. Over the last decade, various attempts have been made to develop techniques for the rapid quantification of E. coli O157:H7. This review covers the importance of E. coli O157:H7 and recent progress (from 2015 to 2020) in the development of the sensitivity and selectivity of electrochemical sensors developed for E. coli O157:H7 using different nanomaterials, labels, and electrochemical transducers.

Etio-Epidemiological Studies on Diarrhoea in Cattle and Buffalo Calves

2020 ◽  
Author(s):  
S K Sharma ◽  
Monika Joshi
Keyword(s):  
Winter Season ◽  
Epidemiological Studies ◽  
Economic Losses ◽  
Buffalo Calves ◽  
Salmonella Spp ◽  
E Coli ◽  
Cryptosporidium Spp ◽  
Faecal Samples ◽  
Eimeria Spp ◽  
Causative Agents

Calf diarrhoea is the most commonly encountered disease syndrome and significant cause of economic losses in dairy industry. Present investigation was undertaken to find out the prevalence of causative agents of diarrhoea in the bovine calves for a period of one year. The effect of age, sex, season and parity of dam was also studied. E. coli was the major organism (86.00 %) observed in the faecal samples of the diarrhoeic calves followed by rotavirus, Eimeria spp. and Amphistomes (15.00 % each); Toxocara spp. (12.00 %); Strongyles (9.00 %); Cryptosporidium spp. (6.00 %); Trichuris spp. (5.00 %); and Salmonella spp. and Strongyloides spp. (3.00 % each). The prevalence of rotavirus, Cryptosporidium spp. and Eimeria spp. was found significantly higher in buffalo calves and crossbred calves than cow calves and Gir / local non-descript calves, respectively. The prevalence of Toxocara spp., Amphistomes and Strongyles in diarrhoeic buffalo calves was significantly higher than cow calves. Highest prevalence of E. coli and rotavirus was observed in faecal samples of diarrhoeic calves of 0-15 days age group. Rotavirus was not detected in faecal samples of diarrhoeic calves above 60 days age. The susceptibility of bovine calves for E. coli and rotavirus was found decreased with the advancement of the age. The prevalence of Salmonella spp. in diarrhoeic faecal samples of bovine calves was observed only in 16-60 days age whereas Cryptosporidium spp. was found only in 0-30 days age. The most of the parasitic infestations were observed after 30 days of age in calves. The calves of both sexes were equally susceptible to different causative agents of diarrhoea. The prevalence of E. coli and most of the helminth ova in the faecal samples of diarrhoeic calves was found maximum during rainy season whereas the rotavirus was observed mostly during winter season. The prevalence of E. coli, Salmonella spp., rotavirus and Cryptosporidium spp. was found highest in the faecal samples of the diarrhoeic calves of first or second parity dams.

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.

Microbiological Quality and Safety of Ready-to-Eat Street-Vended Foods in Johannesburg, South Africa

1999 ◽  
Vol 62 (11) ◽  
pp. 1278-1284 ◽  
Author(s):  
FRANCINA M. MOSUPYE ◽  
ALEXANDER von HOLY
Keyword(s):  
South Africa ◽  
Foodborne Pathogens ◽  
Water Samples ◽  
Microbiological Quality ◽  
Food Samples ◽  
Quality And Safety ◽  
Salmonella Spp ◽  
E Coli ◽  
Bacillus Spp ◽  
Staphylococcus Spp

Fifty-one ready-to-eat street foods, 18 dishwater, and 18 surface swab samples were collected from six vendors in Johannesburg, South Africa. Food temperatures were recorded at the time of sampling. Standard methods were used to determine aerobic plate counts (APCs), spore counts (SCs), and Enterobacteriaceae counts (ECs) for food samples as well as coliform counts (CCs) for water and swab samples. In addition, Petrifilm Escherichia coli count (PC) plates were used for the enumeration of coliforms in food, water, and swab samples. The presence of selected foodborne pathogens in the food samples as well as the presence of nonpathogenic E. coli 1 (in food and water samples) was also tested for. Predominant colonies isolated from APC plates were characterized to the genus level. Holding temperatures for cooked meats and gravies ranged from 42.0 to 94.0°C, and those for uncooked salads ranged from 29.0 to 39.0°C. Mean APC values of 3.4 (±0.4) log CFU/g, 4.0 (±1.2) log CFU/ml, and 2.1 (±0.4) log CFU/25 cm2 were obtained for food, water, and swab samples, respectively. Mean SC values of 1.6 (±0.2) log CFU/g and 1.5 (±0.3) log CFU/25 cm2 were obtained for food and swab samples, respectively. A mean EC value of 2.0 (±0.4) log CFU/g for food samples and mean CC values of 2.5 (±0.3) log CFU/ml and 1.3 (±0.3) log CFU/25 cm2 for water and swab samples, respectively, were determined. Mean PC values of 1.6 (±0.1) log CFU/g, 1.9 (±0.6) log CFU/ml, and 1.4 (±0.4) log CFU/25 cm2 were determined for food, water, and swab samples, respectively. Bacillus cereus was detected in 22%, Clostridium perfringens in 16%, Salmonella spp. in 2%, and E. coli (non-O157:H+) in 2% of the 51 food samples. E. coli was found in 14 water samples (78%) and in 3 food samples (6%). Campylobacter spp., Listeria monocytogenes, Staphylococcus aureus, Vibrio cholerae, and Yersinia enterocolitica were also tested for in the food samples, but they were not detected. The 340 isolates obtained from APC plates for food, water, and swab samples were predominantly Bacillus spp., Micrococcus spp., and Staphylococcus spp. for all three sample types. It was concluded that the foods analyzed in this study were of acceptable quality and safety.

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