scholarly journals The Occurrence of Shiga Toxin-Producing E. coli in Aquaponic and Hydroponic Systems

Horticulturae ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 1 ◽  
Author(s):  
Yi-Ju Wang ◽  
Amanda J. Deering ◽  
Hye-Ji Kim
Keyword(s):  
Food Safety ◽  
Foodborne Pathogens ◽  
Shiga Toxin ◽  
Production Systems ◽  
Salmonella Spp ◽  
Safety Hazards ◽  
E Coli ◽  
Hydroponic Systems ◽  
Microbiological Analyses ◽  
Potential Food

Food safety concerns have been raised over vegetables and herbs grown in aquaponics and hydroponics due to the reuse of wastewater and spent nutrient solutions. This study was conducted to determine the occurrence of foodborne pathogens in greenhouse-based aquaponic and hydroponic systems. Fish feces, recirculating water, roots, and the edible portions of lettuce, basil, and tomato were collected at harvest, and microbiological analyses were conducted for the bacterial pathogens Shiga toxin-producing Escherichia coli (STEC), Listeria monocytogenes, and Salmonella spp. Enrichments and selective media were used for the isolation, and presumptive positive colonies were confirmed by PCR. STEC was found in fish feces, in the water of both systems, and on the surface of the roots of lettuce, basil, and tomato regardless of the system. However, contaminated water did not lead to the internalization of STEC into the roots, leaves, and/or fruit of the plants. Meanwhile, L. monocytogenes and Salmonella spp. were not present in any samples examined. Our results demonstrated that there are potential food safety hazards for fresh produce grown in aquaponic and hydroponic production systems.

scholarly journals Mixed Biofilm Formation by Shiga Toxin–Producing Escherichia coli and Salmonella enterica Serovar Typhimurium Enhanced Bacterial Resistance to Sanitization due to Extracellular Polymeric Substances†

2013 ◽  
Vol 76 (9) ◽  
pp. 1513-1522 ◽  
Author(s):  
RONG WANG ◽  
NORASAK KALCHAYANAND ◽  
JOHN W. SCHMIDT ◽  
DAYNA M. HARHAY
Keyword(s):  
Escherichia Coli ◽  
Food Safety ◽  
Foodborne Pathogens ◽  
Shiga Toxin ◽  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Bacterial Resistance ◽  
Salmonella Enterica Serovar Typhimurium ◽  
E Coli ◽  
Serovar Typhimurium

Shiga toxin–producing Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium are important foodborne pathogens capable of forming single-species biofilms or coexisting in multispecies biofilm communities. Bacterial biofilm cells are usually more resistant to sanitization than their planktonic counterparts, so these foodborne pathogens in biofilms pose a serious food safety concern. We investigated how the coexistence of E. coli O157:H7 and Salmonella Typhimurium strains would affect bacterial planktonic growth competition and mixed biofilm composition. Furthermore, we also investigated how mixed biofilm formation would affect bacterial resistance to common sanitizers. Salmonella Typhimurium strains were able to outcompete E. coli strains in the planktonic growth phase; however, mixed biofilm development was highly dependent upon companion strain properties in terms of the expression of bacterial extracellular polymeric substances (EPS), including curli fimbriae and exopolysaccharide cellulose. The EPS-producing strains with higher biofilm-forming abilities were able to establish themselves in mixed biofilms more efficiently. In comparison to single-strain biofilms, Salmonella or E. coli strains with negative EPS expression obtained significantly enhanced resistance to sanitization by forming mixed biofilms with an EPS-producing companion strain of the other species. These observations indicate that the bacterial EPS components not only enhance the sanitizer resistance of the EPS-producing strains but also render protections to their companion strains, regardless of species, in mixed biofilms. Our study highlights the potential risk of cross-contamination by multispecies biofilms in food safety and the need for increased attention to proper sanitization practices in food processing facilities.

Prevalence of Foodborne Pathogens in Grilled Chicken from Street Vendors and Retail Outlets in Reynosa, Tamaulipas, Mexico

2011 ◽  
Vol 74 (8) ◽  
pp. 1320-1323 ◽  
Author(s):  
A. DÍAZ-LÓPEZ ◽  
R. C. CANTÚ-RAMÍREZ ◽  
E. GARZA-GONZÁLEZ ◽  
L. RUIZ-TOLENTINO ◽  
S. J. TELLEZ-LUIS ◽  
...  
Keyword(s):  
Foodborne Pathogens ◽  
Shiga Toxin ◽  
Daily Consumption ◽  
Salmonella Spp ◽  
Street Vendor ◽  
Street Vendors ◽  
E Coli ◽  
Microbiological Methods ◽  
Two Samples ◽  
Retail Outlets

We analyzed a total of 70 grilled chicken samples bought randomly from street vendors and retail outlets in the city of Reynosa, Mexico, to determine the prevalence of Escherichia coli (Shiga toxin producing and enterotoxin producing), Salmonella spp., Staphylococcus aureus, Listeria spp., and Campylobacter spp. using microbiological methods and PCR detection of bacterial sequences. Of the 70 samples, 27 (38.5%) were from retail outlets and 43 (61.4%) from street vendors. All specimens were negative by both microbiological and molecular methods for Listeria monocytogenes, Shiga toxin 2 of Shiga toxin–producing E. coli, lt of enterotoxin-producing E. coli, and st enterotoxin, and all were negative for Salmonella spp. and Campylobacter jejuni by PCR. Of the samples studied, 49 (70%) had undetectable levels of the foodborne pathogens studied with the methods used. In the remaining 21 (30%) specimens, at least one pathogen was isolated or detected, with E. coli being the pathogen most frequently isolated and with two samples bearing the hlyA gene. We found no statistical difference in bacterial prevalence between retail and street vendor samples. The presence of pathogens in grilled chicken is an important public health risk because of the great demand for and daily consumption of this product in this region.

scholarly journals Effects of Plant Age and Root Damage on Internalization of Shiga Toxin-Producing Escherichia coli in Leafy Vegetables and Herbs

Horticulturae ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 68
Author(s):  
Yi-Ju Wang ◽  
Amanda J. Deering ◽  
Hye-Ji Kim
Keyword(s):  
Escherichia Coli ◽  
Plant Species ◽  
Shiga Toxin ◽  
Production Systems ◽  
Plant Age ◽  
Leafy Vegetables ◽  
Root Damage ◽  
Hygiene Practices ◽  
Hydroponic Systems ◽  
Stx1 Gene

Our previous study reported that fresh produce grown in aquaponic and hydroponic systems can pose potential food safety hazards due to an accidental introduction of contaminated fish and cross-contamination between the systems. In this study, we examined the effects of plant species and age on the likelihood and level of internalization of Shiga toxin-producing Escherichia coli (STEC) in aquaponic and hydroponic systems. Four plant species, basil (Ocimum basilicum L. cv. Genovese), cilantro (Coriandrum Sativum L.), lettuce (Lactuca sativa cv. Cherokee), and kale (Brassica oleracea var. sabellica), received root damage treatment as seedlings before transplanting or mature plants at three weeks after transplanting by cutting off 1-cm tips of one-third of the roots. Enrichments and selective media were used for the isolation, and presumptive positive colonies were confirmed by PCR for the presence of stx1 gene in plant tissues, recirculating water, and fish feces collected at four weeks after transplanting. In hydroponic systems, STEC was found neither in the solution nor in the roots and leaves of all four plant species, possibly through improved sanitation and hygiene practices. However, consistent with our previous findings, STEC was found in the water, on the plant roots, and in the fish feces in aquaponic systems, even after thorough sanitation prior to the study. Regardless of plant age, STEC was internalized in the roots of all plant species when the roots were damaged, but there was no difference in the degree of internalization with STEC among plant species. STEC was present in the leaves only when seedlings received root damage treatment and were grown to maturity, indicating that root damage allows STEC to internalize in the roots within a week, but a longer period is required for STEC to internalize into the leaves. We concluded that root damage on seedlings can cause the internalization of E. coli O157:H7 in the edible parts of leafy vegetables and herbs in soilless production systems.

Insects as vectors of foodborne pathogenic bacteria

2011 ◽  
Vol 4 (1) ◽  
pp. 5-16 ◽  
Author(s):  
Jeffrey Blazar ◽  
Marc Allard ◽  
E. Kurt Lienau
Keyword(s):  
Food Safety ◽  
Foodborne Pathogens ◽  
Pathogenic Bacteria ◽  
Current Knowledge ◽  
Disease Outbreaks ◽  
House Fly ◽  
American Cockroach ◽  
Health Concern ◽  
Foodborne Disease ◽  
Salmonella Spp

AbstractFood safety is an important consideration worldwide. To maintain and improve our current knowledge of foodborne disease outbreaks, we must understand some of the more imminent issues related to food safety. A variety of agents are responsible for transmitting the estimated 76 million cases of illnesses caused by foodborne pathogens every year. This review explores why insects pose a serious health concern, in terms of worldwide food safety initiatives, by looking at evidence in published <abs>Food safety is an important consideration worldwide. To maintain and improve our current knowledge of foodborne disease outbreaks, we must understand some of the more imminent issues related to food safety. A variety of agents are responsible for transmitting the estimated 76 million cases of illnesses caused by foodborne pathogens every year. This review explores why insects pose a serious health concern, in terms of worldwide food safety initiatives, by looking at evidence in published literature. We highlight at least eleven different species of insects, including the lesser mealworm, Alphitobius diaperinus (Panzer); secondary screwworm, Cochliomyia macellaria (Fabricius); synanthropic flies [flesh fly, Sarcophaga carnaria (L.); house fly, Musca domestica (L.); fruit fly, Drosophila melanogaster (Meigen); and stable fly, Stomoxys calcitrans (L.)], American cockroach, Periplaneta americana (L.); German cockroach, Blatella germanica (L.); Oriental cockroach, Blatta orientalis (L.); Pacific beetle cockroach, Diploptera punctata (Eschscholtz); and Speckled feeder cockroach, Nauphoeta cinerea (Olivier), which act as vectors for Salmonella spp. or Escherichia coli and illustrate how these insects are successful vectors of foodborne disease outbreaks. We propose that insects be considered as one of the latest issues in food safety initiatives. Not only are some insects extremely important contributors to diseases, but now we suggest that more research into insects as potential carriers of E. coli and Salmonella spp., and therefore as contributing to foodborne disease outbreaks, is granted.

scholarly journals Assessment of the microbiological quality of popular food items on sale in secondary school canteens of Mauritius

2019 ◽  
Vol 8 (1) ◽  
Author(s):  
Dayawatee Goburdhun ◽  
Mahima D. Beeharry ◽  
Keshnee Reega ◽  
Arvind Ruggoo ◽  
Hudaa Neetoo
Keyword(s):  
Secondary School ◽  
Microbiological Quality ◽  
Viable Count ◽  
Food Type ◽  
Salmonella Spp ◽  
E Coli ◽  
High Level ◽  
Microbiological Analyses ◽  
Composite Samples

This study was carried out to assess the microbiological status of three hot meals served in eight selected school canteens of Mauritius, with two schools randomly selected from each of the four school zones of the island. Three individual samples of farata, panini, or fried noodles were collected at each school during two independent visits. The three individual samples of each food type collected during each visit were then pooled before being subjected to microbiological analyses. A total of 48 composite samples were analyzed. The parameters tested were Total Viable Count (TVC), Escherichia coli, Salmonella spp., Clostridium perfringens, Staphylococcus aureus, and Listeria spp. The microbiological analyses revealed that paninis were deemed as generally acceptable with TVC falling in the range of 3.0-5.7 Log CFU/g and undetectable levels of S. aureus and E. coli. In contrast, fried noodles and faratas harboured a moderately high level of TVC (4.4-6.7 Log CFU/g) and objectionably high levels S. aureus (3.1 to 5.0 Log CFU/g) and E. coli (3.1-5.1 Log CFU/g) for seven out of the eight schools.

scholarly journals Seasonal prevalence and characterization of Shiga toxin-producing Escherichia coli on pork carcasses at three steps of the harvest process at two commercial processing plants in the US

2020 ◽  
Author(s):  
Ivan Nastasijevic ◽  
John W. Schmidt ◽  
Marija Boskovic ◽  
Milica Glisic ◽  
Norasak Kalchayanand ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Foodborne Pathogens ◽  
Shiga Toxin ◽  
Severe Disease ◽  
Control Point ◽  
Plate Count ◽  
Seasonal Effect ◽  
E Coli ◽  
Significant Control ◽  
Pork Products

ABSTRACTShiga toxin (stx) -producing Escherichia coli (STEC) are foodborne pathogens that have a significant impact on public health, with those possessing the attachment factor intimin (eae) referred to as enterohemorrhagic E. coli (EHEC) associated with life threatening illnesses. Cattle and beef are considered typical sources of STEC, but their presence in pork products is a growing concern. Therefore, carcasses (n=1536) at two U.S. pork processors were sampled once per season at three stages of harvest (post-stunning skins; post-scald carcasses; chilled carcasses) then examined using PCR for stx and eae, aerobic plate count (APC) and Enterobacteriaceae counts (EBC). Skins, post-scald, and chilled carcasses had prevalence of stx (85.3, 17.5, and 5.4%, respectively), with 82.3, 7.8, and 1.7% respectively, having stx and eae present. All stx positive samples were subjected to culture isolation that resulted in 368 STEC and 46 EHEC isolates. The most frequently identified STEC were serogroup O121, O8, and O91(63, 6.7, and 6.0% of total STEC, respectively). The most frequently isolated EHEC was serotype O157:H7 (63% of total EHEC). Results showed that scalding significantly reduced (P < 0.05) carcass APC and EBC by 3.00 and 2.50 log10 CFU/100 cm2 respectively. A seasonal effect was observed with STEC prevalence lower (P < 0.05) in winter. The data from this study shows significant (P < 0.05) reduction in the incidence of STEC (stx) from 85.3% to 5.4% and of EHEC (stx+eae) from 82.3% to 1.7% within slaughter-to-chilling continuum, respectively, and that potential EHEC can be confirmed present throughout using culture isolation.IMPORTANCESeven serogroups of Shiga toxin-producing Escherichia coli (STEC) are responsible for most (>75%) cases of severe illnesses caused by STEC and are considered adulterants of beef. However, some STEC outbreaks have been attributed to pork products although the same E. coli are not considered adulterants in pork because little is known of their prevalence along the pork chain. The significance of the work presented here is that it identifies disease causing STEC, enterohemorrhagic E. coli (EHEC), demonstrating that these same organisms are a food safety hazard in pork as well as beef. The results show that most STEC isolated from pork are not likely to cause severe disease in humans and that processes used in pork harvest, such as scalding, offer a significant control point to reduce contamination. The results will assist the pork processing industry and regulatory agencies to optimize interventions to improve the safety of pork products.

Mexican unpasteurised fresh cheeses are contaminated with Salmonella spp., non-O157 Shiga toxin producing Escherichia coli and potential uropathogenic E. coli strains: A public health risk

2016 ◽  
Vol 237 ◽  
pp. 10-16 ◽  
Author(s):  
Rosa Guzman-Hernandez ◽  
Araceli Contreras-Rodriguez ◽  
Rosa Hernandez-Velez ◽  
Iza Perez-Martinez ◽  
Ahide Lopez-Merino ◽  
...  
Keyword(s):  
Public Health ◽  
Escherichia Coli ◽  
Health Risk ◽  
Shiga Toxin ◽  
Salmonella Spp ◽  
Public Health Risk ◽  
E Coli

Microbial Quality, Safety, and Pathogen Detection by Using Quantitative PCR of Raw Salad Vegetables Sold in Dhanbad City, India

2016 ◽  
Vol 80 (1) ◽  
pp. 121-126 ◽  
Author(s):  
SUJEET K. MRITUNJAY ◽  
VIPIN KUMAR
Keyword(s):  
Food Safety ◽  
Quantitative Pcr ◽  
Indian Subcontinent ◽  
Microbiological Quality ◽  
Plate Count ◽  
Salmonella Spp ◽  
Total Coliforms ◽  
E Coli ◽  
Fresh Vegetables ◽  
Salad Vegetables

ABSTRACT Consumption of ready-to-eat fresh vegetables has increased worldwide, with a consequent increase in outbreaks caused by foodborne pathogens. In the Indian subcontinent, raw fresh vegetables are usually consumed without washing or other decontamination procedures, thereby leading to new food safety threats. In this study, the microbiological quality and pathogenic profile of raw salad vegetables was evaluated through standard protocols. In total, 480 samples (60 each of eight different salad vegetables) of cucumber, tomato, carrot, coriander, cabbage, beetroot, radish, and spinach were collected from different locations in Dhanbad, a city famous for its coal fields and often called the “Coal Capital of India.” The samples were analyzed for total plate count, total coliforms, Escherichia coli, E. coli O157:H7, Listeria monocytogenes, and Salmonella spp. Incidences of pathogens were detected through quantitative PCR subsequent to isolation. Results showed that 46.7% (for total plate counts) and 30% (for total coliforms) of samples were unacceptable for consumption per the Food Safety and Standards Authority of India. Pathogenic microorganisms were detected in 3.7% of total samples. E. coli O157:H7 was detected in three samples of spinach (2) and beetroot (1); L. monocytogenes was detected in 14 samples of spinach (8), tomato (3), cucumber (2), and radish (1); and Salmonella spp. were detected in 16 samples of spinach (7), tomato (3), beetroot (2), cucumber (2), carrot (1), and radish (1). Pathogens were not detected in any of the cabbage and coriander samples.

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.

Standardized Microbiological Sampling and Testing Procedures for the Beef Industry†

1996 ◽  
Vol 59 (7) ◽  
pp. 778-780 ◽  
Author(s):  
KELLY J. KARR ◽  
ELIZABETH A. E. BOYLE ◽  
CURTIS L. KASTNER ◽  
JAMES L. MARSDEN ◽  
RANDALL K. PHEBUS ◽  
...  
Keyword(s):  
Total Coliform ◽  
Plate Count ◽  
Escherichia Coli O157 ◽  
Beef Industry ◽  
Salmonella Spp ◽  
Testing Procedures ◽  
E Coli ◽  
Aerobic Plate Count ◽  
Reported Data ◽  
Microbiological Analyses

Standardized microbiological sampling and testing procedures were developed that can be used throughout the beef slaughter and processing industry to facilitate the collection and any desired compilation of comparative data. Twenty samples each from carcasses (brisket, flank, and rump areas combined); subprimal cuts (clods); lean trim; and cutting and/or conveyor surfaces were collected in three slaughter and processing operations, with the first operation being a preliminary trial and resulting in no reported data. Microbiological analyses for Clostridium perfringens, Escherichia coli O157:H7, Listeria monocytogenes, Salmonella spp., Staphylococcus aureus, Campylobacter jejuni/coli, total coliforms, E. coli Biotype I, and aerobic mesophilic bacteria (aerobic plate count, APC) were performed on all samples by an outside laboratory. The procedures developed were effective in allowing samples to be collected, shipped, and analyzed in the same manner for all operations. From a logistical standpoint, approximately 20 samples each of carcasses, clods, lean trim, and surfaces could be taken within 4 to 6 h by five people. Forty samples each of carcass, clod, lean trim, and conveyor surfaces from two plants tested negative for E. coli O157:H7, Salmonella spp., and Listeria spp., with the exception of L. monocytogenes being isolated from one carcass and one clod sample. APCs and total coliform counts were between 103 to 105 and 102 to 103 CFU/cm2 or CFU/g, respectively, for the 40 samples each of carcasses, clods, and lean trim. APCs for surface swab counts ranged from ≤ 10 to 103 CFU/cm2.

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