Search

Objective: Although it is thought that human stomach acidity would inhibit microorganisms, when food poisoning cases are considered, it is seen that especially during consumption of meat and meat products, the pH in the stomach rises and the fat layer creates a protective effect on bacteria, allowing microorganisms to transfer to intestine, and subsequently cause foodborne illnesses. The aim of this study was to determine whether beverage intake with meals influences why some individuals get sick, while others do not in food poisoning outbreak cases. Methods: The effect of coke, ayran and shalgam, which are popularly consumed beverages along with meals in Turkey, was examined on the survival of Salmonella enteritidis, Listeria monocytogenes. Escherichia coli O157: H7 and cocktail of these pathogens in simulated gastric fluid (SGF). Doner, a worldwide popular fast-food product, was used as the food sample. Results: Shalgam was found to be noteworthy that provided the greatest reduction in pathogen count. It was observed that in vitro consumption of one serving (300 mL) of shalgam, coke, and ayran along with contaminated doner, reduced the pathogenic bacteria count in SGF up to 2.6, 2.25 and 1.6 log CFU/g, respectively. The results showed that consuming those beverages alongside one portion (100 g) of low contaminated (~101 CFU/g) doner might eliminate the possibility of a healthy person having foodborne illness due to aforementioned bacteria. Conclusion: It can be concluded that, in food poisoning cases, not only the personal immune system, but also the type and amount of beverage consumed along with food, as well as the amount of food intake are effective. [ABSTRACT FROM AUTHOR]

Escherichia coli O157:H7 is an important food borne pathogen related to public health. Antibody molecules are the most important effector molecules in the humoral immune response. They have a variety of biological activities. The main biological function is to specifically bind to the corresponding antigen. Aptamers are shorter DNA sequences synthesized in vitro, which can bind specifically by recognizing specific regions and targets. Based on the specific recognition function of antibody and aptamer, the capture effect and magnetic separation of immunomagnetic beads, and the construction of biosensor by polyclonal antibody and tailoring aptamer, real‑time fluorescence quantitative polymerase chain reaction（qPCR）may achieve the detection of target at (8×103 )-(8×106 ) CFU/mL. The limit of detection is 800 CFU/mL for quantitative detection [ABSTRACT FROM AUTHOR]

Escherichia coli O157: H7 is a representative foodborne pathogen that causes haemorrhagic colitis, bloody diarrhea, and fatal haemolytic uraemic syndrome. Previously, only conventional heat treatment was used to pasteurised food; however, this method decreases food quality, including colour change, denatures proteins, and causes lipid oxidation. Therefore, emerging technologies to inactivate pathogens in food that affect food quality minimally have been researched and developed. This review aims to compile research since 2018 and briefly describe the inactivation mechanisms of emerging technologies such as microwave, radio frequency, ohmic heating, superheated steam, ionising radiation (gamma irradiation, electron beam, and X-rays), high pressure, ultraviolet light, pulsed light, ultrasound, gas treatment, plasma, and combination treatments. Pulsed electric field and electrolysed water were excluded because few research papers were published after 2018. In addition, the shortcomings of emerging technologies in the control of E. coli O157: H7 and the directions for emerging technology research are presented. Taking advantage of emerging technologies with many benefits will significantly improve food safety. [ABSTRACT FROM AUTHOR]

Coliforms, especially Escherichia coli, are one of the most important causes of gastroenteritis and microbial index of water and food contamination. Enterohemorrhagic Escherichia coli strains are considered to be the most important intestinal pathogens due to hemorrhagic diarrhea and hemolytic syndrome, of which E. coli O157: H7 is the most important and common. The purpose of this study was to investigate the prevalence of E. coli O157: H7 contamination in traditional and homemade ice creams and compare the efficiency of chromogenic media with standard media for its detection. In this study, 90 samples of traditional ice cream from the production and distribution centers of this product were collected from three urban regions of Bandar Abbas, in two warm and cold seasons and in order to count the coliforms and detect E. coli and E. coli O157: H7, two standard and chromogenic methods were used. The results indicated that 81.8% of samples had more than the standard number of coliforms, and 28.9% of the samples were contaminated with E. coli. E. coli O157: H7 contamination was detected 2.2% and 4.4% using standard and chromogenic methods, respectively. Analyzes showed that application of media containing chromogenic substances, E. coli O157: H7 could be detected with the least possible error. It was found that the use of chromogenic culture media to identify E. coli O157: H7 was better than the standard method. The results of the present study also indicate that the quality and health status of traditional and handmade ice creams should be more closely monitored. [ABSTRACT FROM AUTHOR]

Escherichia coli O157:H7 human infections are mostly associated with consumption of raw or undercooked beef and raw milk. Ruminants, especially cattle are the main reservoir of the pathogen. The main aim of the present study was to evaluate the occurrence of E. coli O157:H7 in cattle dairy farm and beef production level in Estonia. It was found that E. coli O157:H7 is present at both the dairy farm and slaughterhouse level. The occurrence of the pathogen at Estonian dairy farm level was 1.2% from 1312 cattle's sampled. At slaughterhouse level 744 hide swabs were taken from which 30 (4.0%) were positive to E. coli O157:H7. Both stx1 and stx2 genes were determined from isolates and often the combination of both genes was found to be present. Minimal inhibitory concentration was determined for 30 E. coli O157:H7 isolates which revealed 26.7% of multiresistant isolates. In 2009–2010 in a total of 188 beef samples were analysed, which all were negative for O157:H7.

Escherichia coli serotype O157:H7 is a recently recognized human pathogen associated with hemorrhagic colitis. This work was therefore aimed at isolating Esherichia coli O157 from human stool. A total of 100 stool samples were collected from patients with age ranging from (0-05) years, statistical analysis of the risk factors showed that only zero to five years age range of the respondents had a significant statistical difference of 0.012 (P

Escherichia coli O157: H7 is a pathogenic bacterium which is recognized for the ability to resist multiple antibiotics; accordingly, complications occur in the treatment of infections caused by this bacterium. The Ib-M1 peptide and the IONP @ Ib-M1 bioconjugate have emerged as a new antimicrobial alternatives against E. coli O157: H7. The mechanism of action of Ib-M1 and IONP @ Ib-M1 against this bacterium is still unknown; therefore, the goal of this research was to identify the change in the proteins profile of E. coli O157: H7 after treatment with Ib-M1 and IONP @ Ib-M1 as a first step to determine its mechanism of action. For this, the proteins were obtained first, and then a two-dimensional electrophoresis was performed to finally determine the variability of the protein profiles. Once the protein profiles were obtained, an analysis of variance (ANOVA) was carried out. 72 differentially expressed proteins were identified, which can be connected to the effect on the bacterium's growth in the presence of Ib-M1 and IONP @ Ib-M. These proteins are involved in acyl groups transfer processes (Yhbs protein), lipoprotein translocation (LolA protein) and amino acid transport (GpmA protein), among others. [ABSTRACT FROM AUTHOR]

A six‐strain mixture of E. coli O157:H7 was exposed to 0 to 9 min of six treatments: (i) hydrostatic pressure (400 MPa) at 4 °C; (ii) hydrostatic pressure and thymol at 4 °C; (iii) thymol at 4 °C; (iv) heat at 40 °C; (v) hydrostatic pressure at 40 °C; and (vi) hydrostatic pressure and thymol at 40 °C. Pressure intensity level of 400 MPa and thymol concentration of 0.15% (w/v) were used for the experiments of inoculated pathogen (4.0 to 5.0 log CFU/mL) in a homogenate (10% nonsterilized beef in 90% sterilized distilled water). Temperature was precisely monitored by stainless steel water jacket surrounding pressure chamber (16 mL volume), mechanically linked to a refrigerated circulating water bath. Analyses of variance were conducted followed by Tukey‐ and Dunnett's‐adjusted mean separations. Pathogen counts before treatment were 4.08 ± 0.7 log CFU/mL and were reduced (P < 0.05) to 0.67 ± 0.2 log CFU/mL after 6 min of pressure treatment. Thymol and mild heat (40 °C) further augmented decontamination efficacy of pressure treatments where in their presence, the mesophilic background microbiota counts of pressure‐treated samples after 3, 6, and 9 min were reduced (P < 0.05) by 2.1, 2.5, and 3.1 log CFU/mL, respectively. Results of the current study indicate that thymol and mild heat could enhance decontamination efficacy of elevated hydrostatic pressure for pasteurization of food commodities. This could be of great significance for industry practitioners to assure microbiological safety of a product and cost optimization by benefiting from synergism of antimicrobials, mild heat, and elevated hydrostatic pressure. Practical Application: Thymol and mild heat could enhance decontamination efficacy of pressure‐based pasteurizer that could be of great significance for practitioners. Application of pressure coupled with antimicrobial and mild heat could assure microbiological safety of a product, lead to cost optimization, and assist in meeting regulatory requirements of food commerce such as Hazard Analysis and Critical Control Point and Preventive Control for Human Food rule of Food Safety Modernization Act. Addition of an antimicrobial could have further co‐benefits for the product due to residual protective effects during shelf‐life and minimizing potential undesirable organoleptic changes associated with pressure treatments of >400 MPa. [ABSTRACT FROM AUTHOR]

Escherichia coli O157: H7 is one of the most important pathogens causing food poisoning in meat products. In this study, the antimicrobial effects of Lavandula angustifolia and NaCl on growth control of Escherichia coli O157: H7 inoculated into minced beef during storage were investigated. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of Lavender essential oil for Escherichia coli O157: H7 were determined 0.625% and 1.25% by micro broth dilution method, respectively. Lavender essential oil was added to the minced meat in three concentrations (0, 0.5 and 1%) and NaCl in three concentrations (0, 2 and 4%). Subsequently, Escherichia coli O157: H7 was inoculated into minced meat at 105 CFU/gr. Minced meat treatments with Escherichia coli O157: H7 were counted on days (0, 3, 6 and 9) kept at refrigerated temperature (4 °C). The results showed that growth control of Escherichia coli O157: H7 of all treatments was significant (P<0.05) and mean log CFU/gr of bacterial count in 9 days was lower in all groups than control. Comparatively, the effect of NaCl alone was greater than that of essential oil alone. The greatest inhibitory effect was related to the simultaneous use of essential oil and NaCl. [ABSTRACT FROM AUTHOR]

Escherichia coli serotype O157: H7 and Shigella dysenteriae type 1 as the Shiga toxin‐producing bacteria cause some acute gastrointestinal and extraintestinal diseases such as hemorrhagic uremic syndrome and bloody diarrhea in human. Stx genes are the key virulence factors in these pathogens. The aim of this study was to develop HRMA assay to differentiate stx1A gene for detection of E. coli serotype O157: H7 and Sh. dysenteriae type 1 and determine the prevalence of these pathogens in food samples using this method. PCR‐HRMA assay and gold standard methods have been carried out for identification of pathogens among 135 different food samples. We found HRMA method a sensitive and specific assay (100 and 100%, respectively) for differentiation of stx1A gene, consequently, detection of these pathogens in food samples. Also, the highest prevalence of E. coli serotype O157: H7 and Sh. dysenteriae type 1 harboring stx1A gene was observed in raw milk and vegetable salad samples, respectively. HRMA as a rapid, inexpensive, sensitive and specific method is suggested to be used for differentiation of stx1A gene to detect E. coli serotype O157: H7 and Sh. dysenteriae type 1 as the key pathogens for safety evaluation of food samples. [ABSTRACT FROM AUTHOR]

Background: Diarrhea is a leading cause of morbidity and mortality in children aged less than five years. Escherichia coli O157: H7 is a highly pathogenic subgroup of Shiga toxin-producing E. coli (STEC) that causes severe human bloody diarrhea and hemolytic uremic syndrome. Objectives: To determine the rates of detection of E. coli O157: H7 infections in children less than five years of age and to assess the clinical and laboratory criteria of E. coli O157: H7 associated diarrhea. Patients and Method: Across sectional prospective, hospital-based study was carried out on children with acute diarrhea visiting the outpatientclinics at Children Welfare Teaching Hospital, AL-Kadhymia Pediatric Hospital and AL-Elweya Pediatric Hospital in Baghdad during the period from Sep. to Dec. 2015. E.coli O157: H7 antigen in fecal samples taken from children with acute diarrhea were detected by immunochromatographic assay (ICA). Results: Escherichia coli O157: H7 antigen was detected in 43/94(45.7%) of fecal samples for children with diarrhea. 55.8% of children with positive stool samples were females and 44.2% were males with a female to male ratio of 1.3:1. Children with acute diarrhea due to E. coli O157: H7 were younger (mean age 17.19 ± 9.572 months) than those without E. coli O157: H7 infection (mean age 30.63 ±19.815 months) and the difference is highly significant. Fever and vomiting were symptoms shared by all the studied children regardless of their E.coli O157: H7 infections. Significant associations between bloody diarrhea, pus and red blood cells in stools and E. coli O157: H7 infections were noted. Conclusions: E. coli O157: H7 infectionwas a common cause of gastroenteritisin children less than five years in Baghdad.Mainly among infants and young children who presented with acute bloody diarrhea, microscopic pus and red blood cells in their stools. [ABSTRACT FROM AUTHOR]

Aims: The aim of this study was to develop a multiplex touchdown PCR (multiplex TD‐PCR) for rapid and simultaneous detection of four major foodborne pathogens to avoid mispriming and unwanted production during gene amplification. Touchdown PCR is the modified form of standard PCR, which enhances specificity, sensitivity. Methods and Results: For this reason, a multiplex TD‐PCR assay with a pre‐enrichment step was developed to detect four foodborne pathogens namely Escherichia coli O157:H7, Listeria monocytogenes, Staphylococcus aureus, and Salmonella enterica serovar Enteritidis in pure culture and raw milk samples. The results showed that this protocol can eliminate the unwanted band or reduce significantly. The detection sensitivity of the single and multiplex TD‐PCR was one cell per ml in pure culture. Furthermore, the detection limit of multiplex TD‐PCR was one cell per 25 ml for artificially contaminated raw milk. We obtained similar results for detection of aforementioned pathogens in raw milk, after comparing the multiplex TD‐PCR method with the traditional culture, except in one or two samples. Conclusions: Hence, the proposed multiplex TD‐PCR method could be confirmed as an effective way for rapid optimization of PCR reactions to increase specificity, sensitivity during gene amplification. Significance and Impact of the Study: Hence, due to its simplicity, cost‐effectiveness and being time‐saving, it seems that this method is reasonable and economical for rapid optimization of PCR reactions. [ABSTRACT FROM AUTHOR]

In this research, the effects of whey protein concentrate based edible coatings containing different concentrations of natamycin and lysozyme–xanthan gum conjugate were investigated. For this purpose, Escherichia coli O157:H7 (as an indicator for gram negative bacteria and also resistant to commercial pasteurization), Staphylococcus aureus (as an indicator of gram-positive bacteria), and Penicillium chrysogenum were inoculated to ultrafiltrated white cheese surface and the microbial properties of cheese samples were evaluated during 28 days storing.The results showed that all coated treatments significantly reduced the growth of Penicillium chrysogenum. Natamycin-containing coatings have been more effective in reducing the mold population than lysozyme-xanthan-containing coatings. Coated samples containing 600 ppm lysozyme-xanthan reduced E. coli O157: H7 growth 2.09 log compared to control samples.Also, the growth rates of Staphylococcus aureus were lower in all samples treated with lysozyme-xanthan than control sample. The lowest growth rate of Staphylococcus aureus was observed in the coated sample containing 600 ppm lysozyme-xanthan on 28th day, with a microbial population of 2.60 logarithms. Unlike other treatments, the growth rate of Staphylococcus aureus in the sample coated containing 600 ppm lysozyme-xanthan was descending over 28 days.The results of this study showed that whey protein based edible coating can be used as a carrier of natamycin and lysozyme-xanthan in optimal concentration, for increasing the microbial quality of UF cheese. [ABSTRACT FROM AUTHOR]

The presence of Shiga-toxin producing Escherichia coli (STEC) was evaluated in bulk milk from dairy cattle farms in Bulgaria. From 20 regional farms only 4 were selected as a source for milk sampling on the basis of their annual STEC shedding in feces. All the samples were PCR analyzed after selective enrichment. Positive samples were detected in subsequent molecular testing as: two of samples (9.08%) were positive for stx1, one sample (4.54%) for stx2, 10 samples (45.54%) for eae and 12 (54.54%) for H7 coding genes. [ABSTRACT FROM AUTHOR]

The present study was conducted to investigate the prevalence of Escherichia coli (E. coli) O157:H7 and to determined its virulence genes (stx1 and stx2, eaeA and ehlyA) in different samples collected from a poultry cutting satages in Samsun province, Turkey. For this purpose, 40 viscera, 40 intestinal content, 20 scalding tank water and 100 swap samples taken from various poultry processing units (plucking machine, cutting board, removing unit of intestinal organs and personnel hands and broiler carcass) were analysed. All samples were analyzed for the isolation of E. coli O157:H7 through pre-enrichment in modified tryptone soy broth supplemented with novobiocin (mTSB+N) followed by immunomagnetic separation (IMS) and selective plating on CHROM agar with Cefixim - Tellurite. Presumptive E. coli O157:H7 isolates were tested with anti-O157 and H7 antisera. Polymerase Chain Reaction (PCR) was performed on isolates for the detection of rfbO157, fliCH7,stx1, stx2, eaeA and ehylA genes. In this study, two intestinal content (1%) isolates were identified as E. coli O157 while were found negative for H7. Both isolates contained stx1, stx2, eaeA and ehylA genes. As a result of this study, it was concluded that E. coli O157 isolates detected at low levels in the broiler intestinal contents might constitute a significant hazard for human health due to the presence of toxin genes. [ABSTRACT FROM AUTHOR]

Pathogens, mycotoxins, or antibiotics may exist in a food sample. Micro- and macromolecular substances must be detected quickly. A rapid and convenient lateral flow immunoassay (LFI) integrated with competitive and sandwich models was developed to detect micro- and macromolecular substances. In this study, aflatoxin M1 (AFM1) and Escherichia coli O157:H7 were selected as the micro- and macromolecular substances, respectively. Two test lines in the LFI test strip were evaluated to detect AFM1 and E. coli O157:H7 by competitive and sandwich models. Results showed that the limits of detection for detecting AFM1 and E. coli O157:H7 were 50 pg·mL−1 and 1.58 × 104 cfu·mL−1, respectively. The whole assay time was 30 min. The recoveries of gold nanoparticle-LFI ranged from 78.0 to 111.6% with coefficients of variation in the range of 3.9 to 8.5% for the detection of AFM1. For the detection of E. coli O157:H7, the range of recoveries was from 70.1 to 89.6% with coefficients of variation ranging from 4.9 to 13.0%. This study not only tested sensitivity and specificity, but also was a systematic study of location of 2 test lines of the LFI test strip integrated with competitive and sandwich models. [ABSTRACT FROM AUTHOR]

Escherichia coli O157:H7 human infections are mostly associated with consumption of raw or undercooked beef and raw milk. Ruminants, especially cattle are the main reservoir of the pathogen. The main aim of the present study was to evaluate the occurrence of E. coli O157:H7 in cattle dairy farm and beef production level in Estonia. It was found that E. coli O157:H7 is present at both the dairy farm and slaughterhouse level. The occurrence of the pathogen at Estonian dairy farm level was 1.2% from 1312 cattle's sampled. At slaughterhouse level 744 hide swabs were taken from which 30 (4.0%) were positive to E. coli O157:H7. Both stx1 and stx2 genes were determined from isolates and often the combination of both genes was found to be present. Minimal inhibitory concentration was determined for 30 E. coli O157:H7 isolates which revealed 26.7% of multiresistant isolates. In 2009-2010 in a total of 188 beef samples were analysed, which all were negative for O157:H7. [ABSTRACT FROM AUTHOR]

Bacteria treated with chlorine-based sanitizer could enter into viable but non-culturable (VBNC) state, which may be underestimated its health risk. In this study, E. coli O157: H7 was treated with slightly acidic electrolyzed water (SAEW), acidic electrolyzed water (AEW) and sodium hypochlorite with different available chlorine concentrations (ACC). The reduction of population was determined, as well as the status of treated cells (viable and culturable, VBNC, dead) was assayed using flow cytometry combined with plate counting. Finally, the cell which cannot be detected using routine media was cultured in p-TSB to resuscitate. The results showed that the reduction of E. coli O157: H7 increased with increasing ACC of SAEW, AEW and sodium hypochlorite and the antimicrobial effect of electrolyzed oxidizing (EO) waters was much higher than sodium hypochlorite. SAEW, AEW and sodium hypochlorite with ACC of 30, 20 and 60 mg/L achieved E. coli O157: H7 colonies to non-detectable level on solid media. The results obtained from flow cytometric assay indicated that culturable cells after EO water and sodium hypochlorite treatments with increasing ACC firstly enter VBNC state and then transferred to dead status. VBNC E.coli was able to be resuscitated in p-TSB and therefore regarded as a potential risk for human health. E. coli O157: H7 in VBNC state after EO water treatment should be taken into consideration and complete inactivation could be achieved by elevated chlorine concentration. [ABSTRACT FROM AUTHOR]

This study was performed to investigate molecular characterization of Shiga toxin-producing E. coli associated with acute diarrhea (bloody, watery or both) that collected from Children under 5 years old in Babylon province. For the detection of the pathogenic E. coli O157:H7 virulence genes (stx1, stx2, eaeA, hlyA) in a multiplex PCR protocol using fourspecific primer pairs. The target genes produced species-specific amplicons at (614bp), (779bp), (890bp) and (165bp), respectively. A total of 500 stool samples were collected, cultured on theSorbitol MacConkey agar and E. coli 0157: H7 Chromogenic Agar Base with cefixime tellurite supplement. Out of the 500 samples, 223 (44.6%) were non-sorbitol fermenting (NSF). E. coli isolates were serotyped as E. coli O157:H7 11(2.2%), byserological detection of O157 somatic antigen by using slide agglutination of heat-treated organisms and Vitek2 system. All latex agglutination positive isolates were positive to mPCR test. The results obtained show that the established PCR protocol is suitable for a rapid and specific analysis of the pathogenic E. coli O157:H7 in clinical samples for the assessment of microbiological risks. [ABSTRACT FROM AUTHOR]

Escherichia coli serotype O157:H7 is a recently recognized human pathogen associated with hemorrhagic colitis. This work was therefore aimed at isolating Esherichia coli O157 from human stool. A total of 100 stool samples were collected from patients with age ranging from (0-05) years, statistical analysis of the risk factors showed that only zero to five years age range of the respondents had a significant statistical difference of 0.012 (P<0.05). The presumptive Esherichia coli isolates that appeared as pink flat lactose fermenting on MacConkey Agar and green metallic sheen on Eosin Methylene Blue agar were picked and confirmed biochemically as Esherichia coli using biochemical test kit. The confirmed E. coli isolates were then cultured on Sorbitol MacConkey Agar which shows non sorbitol fermenting. Detection of E. coli O157:H7 on SMAC medium had a sensitivity of 100%, a specificity of 85%, and an accuracy of 86%. SMAC medium stool culture is a simple, inexpensive, rapid, and reliable means of detecting E. coli O157:H7. Although 1.39% prevalence rate of Esherichia coli O157 was obtained it is pertinent to note that, Esherichia coli O157 is becoming a public health threat because of the debilitating effects it has on humans and also due to its low infectivity dose. There is therefore, the need for more public awareness to educate our citizens on ways of improving on the unsanitary environment. [ABSTRACT FROM AUTHOR]

Food Microbial contamination is one of the most serious problems. A large percentage of food-borne illnesses are caused by food-borne pathogens, and diarrheal agents comprise more than half of the overall prevalence of food-borne illnesses in the globe, and more commonly in developing countries. This study aimed to identify the most-common foodborne organisms from foods in Khartoum state by PCR. A total of 207 food samples (raw milk, fresh cheese, yogurt, fish, sausage, mortadella, and eggs) were collected. DNA was extracted from food samples by guanidine chloride protocol, and then species-specific primers were used to identify Escherichia coli O157: H7, Listeria monocytogenes , Salmonella spp., Vibrio cholerae , V. parahaemolyticus , and Staphylococcus aureus. Out of 207 samples, five (2.41%) were positive for L. monocytogenes , one (0.48%) was positive for S. aureus, and one (0.48%) was positive for both Vibrio cholerae and Vibrio parahaemolyticus. From 91 fresh cheese samples, 2 (2.19%) were positive for L. monocytogenes, and one (1.1%) sample was positive for two different foodborne pathogens (V. cholerae and V. parahaemolyticus). Out of 43 Cow's milk samples, three (7%) samples were positive for L. monocytogenes , and out of 4 sausage samples, one (25 %) was positive for S. aureus. Our study revealed the presence of L. monocytogenes and V. cholera in raw milk and fresh cheese samples. Their presence is considered a potential problem and needs intensive hygiene efforts and standard safety measures before, during, and after food processing operations. [ABSTRACT FROM AUTHOR]

We report results of the studies relating to fabrication of the graphene wrapped copper (II) assisted cysteine hierarchical structure (rGO-CysCu, 10 μm) synthesised using facile, aqueous and environmental-friendly conditions. The results of electrochemical impedance spectroscopic investigations indicate that self-assembly of rGO-CysCu molecules onto gold electrode provides a high surface area and high electron transfer rate constant (1.82 × 10 −6 cm/s). Further, an ultrasensitive label-free electrochemical immunosensor for quantitative determination of Escherichia coli O157: H7 ( E. coli ) has been developed using rGO-CysCu as the sensing layer. Under optimal conditions, the calibration plot pertaining to sensing characteristics of the fabricated immunoelectrode for E. coli O157: H7 was approximately linear in the wide detection range of 10 CFU mL −1 to 10 8 CFU mL −1 with a detection limit of 3.8 CFU mL −1 . Moreover, the proposed method was successfully used to differentiate the E. coli O157: H7 cells from the non-pathogenic E. coli (DH5α) and other bacterial cells in the synthetic samples. [ABSTRACT FROM AUTHOR]

Background: Enterohaemorrhagic Escherichia coli (EHEC), like E. coli O157:H7 are frequently detected in bovine faecal samples at slaughter. Cattle do not show clinical symptoms upon infection, but for humans the consequences after consuming contaminated beef can be severe. The immune response against EHEC in cattle cannot always clear the infection as persistent colonization and shedding in infected animals over a period of months often occurs. In previous infection trials, we observed a primary immune response after infection which was unable to protect cattle from reinfection. These results may reflect a suppression of certain immune pathways, making cattle more prone to persistent colonization after re-infection. To test this, RNA-Seq was used for transcriptome analysis of recto-anal junction tissue and ileal Peyer's patches in nine Holstein-Friesian calves in response to a primary and secondary Escherichia coli O157:H7 infection with the Shiga toxin (Stx) negative NCTC12900 strain. Non-infected calves served as controls. Results: In tissue of the recto-anal junction, only 15 genes were found to be significantly affected by a first infection compared to 1159 genes in the ileal Peyer's patches. Whereas, re-infection significantly changed the expression of 10 and 17 genes in the recto-anal junction tissue and the Peyer's patches, respectively. A significant downregulation of 69 immunostimulatory genes and a significant upregulation of seven immune suppressing genes was observed. Conclusions: Although the recto-anal junction is a major site of colonization, this area does not seem to be modulated upon infection to the same extent as ileal Peyer's patches as the changes in gene expression were remarkably higher in the ileal Peyer's patches than in the recto-anal junction during a primary but not a secondary infection. We can conclude that the main effect on the transcriptome was immunosuppression by E. coli O157:H7 (Stx-) due to an upregulation of immune suppressive effects (7/12 genes) or a downregulation of immunostimulatory effects (69/94 genes) in the ileal Peyer's patches. These data might indicate that a primary infection promotes a re-infection with EHEC by suppressing the immune function. [ABSTRACT FROM AUTHOR]

Background: Several occupational diseases of multiple origins are encountered among abattoir workers. Presence of indicator microorganisms (coliforms) on hands of workers can be used a gauge for hygienic practices. Methods: A cross-sectional study was performed to assess the prevalence of E.coli and enterobacteriaceae among Halal abattoir workers in some government halal abattoirs of Malaysia. A total of one hundred and sixty-five hand swab samples were collected from workers of Halal abattoirs in Malaysia. The samples were subjected to microbiological analysis for characterisation and serotyping. Results: The results have shown that no Escherichia coli O157:H7 was isolated on the hands of abattoir workers before and after work. However, a total prevalence of 9.7% was recorded for all samples during work. For non-O157:H7, total prevalence of 33.3% during work and 13% after work were obtained. High prevalence was recorded in sample taken during work from Tampin, Jasin and Kemaman (100% each) while low prevalence where observed in Shah Alam, Banting and Ipoh (20% each). Conclusions: Based on the findings the hygienic practices of hand washing among the workers in few locations was found to be low especially after work. [ABSTRACT FROM AUTHOR]

The focus of this study was to evaluate the effect of γ radiation and chilling on the hygienic quality of fresh beef meat, fatty acids content and survival of Escherichia coli as food poisoning microorganisms. Sixty fresh beef samples were hygienically examined, surveyed for E. coli O157: H7; eight samples were positive (13.3%). Sensory examination revealed that there were no significant changes between γ radiated (at 3 kGy) and non-irradiated groups in color, odor and texture. γ radiation caused slight significant effect on the chemical analysis after irradiation; there was no significant changes in pH values it slightly increased the amount of total volatile basic nitrogen (TVN), thiobarbituric acid reactive substances (TBA) and peroxide value. Fatty acids of irradiated chilled samples were slightly affected as compared with control samples; the irradiated samples had higher saturated fatty acid content (C16:0, C18:0) and lower unsaturated fatty acid content (C18:1, C18:2) than the non-irradiated sample. We recommend exposing meat to 3 kGy of γ radiation to prolong its chilling life hygienically. [ABSTRACT FROM AUTHOR]

BACKGROUND High hydrostatic pressure ( HHP) combined with reuterin and lactoperoxidase system ( LPS) has exerted antimicrobial activity against Listeria monocytogenes in cold-smoked salmon at chilled temperatures. Therefore the purpose of this work was to evaluate the effect of HHP combined with reuterin, LPS and lactoferrin ( LF) on the survival of Salmonella enterica subsp. enterica serovar Enteritidis and Escherichia coli O157: H7 in cold-smoked salmon stored at 4 and 10 °C. RESULTS Salmonella Enteritidis and E. coli O157: H7 were reduced more than 3 log colony-forming units ( CFU) g−1 by the pressure treatment (450 MPa/5 min). LPS slightly diminished pathogen levels throughout storage, whereas no effect was recorded when reuterin or LF was added. The Salmonella population was below the detection limit (<1 log CFU g−1) during the storage of HHP-treated smoked salmon at 4 and 10 °C. The antimicrobial activity of HHP against E. coli O157: H7 was increased when 450 MPa was applied in combination with LPS in cold-smoked salmon at 4 and 10 °C. CONCLUSION HHP at 450 MPa/5 min inactivated S. Enteritidis in cold-smoked salmon and in combination with LPS would be useful as a hurdle technology approach against E. coli O157: H7, even under mild temperature abuse conditions. © 2015 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The Centers for Disease Control and Prevention recently emphasized the need for enhanced technologies to use in investigations of outbreaks of foodborne illnesses. To address this need, e-probe diagnostic nucleic acid analysis (EDNA) was adapted and validated as a tool for the rapid, effective identification and characterization of multiple pathogens in a food matrix. In EDNA, unassembled next generation sequencing data sets from food sample metagenomes are queried using pathogen-specific sequences known as electronic probes (e-probes). In this study, the query of mock sequence databases demonstrated the potential of EDNA for the detection of foodborne pathogens. The method was then validated using next generation sequencing data sets created by sequencing the metagenome of alfalfa sprouts inoculated with Escherichia coli O157:H7. Nonspecific hits in the negative control sample indicated the need for additional filtration of the e-probes to enhance specificity. There was no significant difference in the ability of an e-probe to detect the target pathogen based upon the length of the probe set oligonucleotides. The results from the queries of the sample database using E. coli e-probe sets were significantly different from those obtained using random decoy probe sets and exhibited 100% precision. The results support the use of EDNA as a rapid response methodology in foodborne outbreaks and investigations for establishing comprehensive microbial profiles of complex food samples. [ABSTRACT FROM AUTHOR]

Medicinal plants have been used for treating diarrhoea but the interference mechanisms are not clearly understood. One possible hypothesis is that of an effect on cell surface hydrophobicity of microbial cells. In this study, we examined cell aggregation affected by crude extracts of Thai medicinal plants on cell surface hydrophobicity of Escherichia coli strains by salt aggregation test. Correlation between minimal inhibitory concentration and cell aggregation was performed. Aqueous and ethanolic extracts of 8 medicinal plants including Acacia catechu, Holarrhena antidysenterica, Peltophorum pterocarpum, Piper sarmentosum, Psidium guajava, Punica granatum, Quercus infectoria, and Tamarindus indica were tested with E. coli O157: H7 and other E. coli strains isolated from human, porcine, and foods. Aqueous extracts of Peltophorum pterocarpum, Psidium guajava, and Punica granatum were highly effective against E. coli O157: H7 with the MIC values of 0.09 to 0.39, 0.19 to 0.78, and 0.09 to 1.56 mg/ml, respectively. Ethanolic extract of Quercus infectoria and Punica granatum demonstrated good MIC values of 0.09 to 0.78, and 0.19 to 0.78 mg/ml, respectively. It was established that aqueous extracts of Punica granatum and Piper sarmentosum at high concentration (25 mg/ml) enhanced cell aggregation of almost all E. coli strains while aqueous and ethanolic extracts ofQuercus infectoria enhanced cell aggregation of some E. coli strains. Correlation between minimal inhibitory concentration and cell aggregation was not found in this study.

Se estudió el efecto de cultivos probióticos sobre Listeria monocytogenes y Escherichia coli O157:H7 inoculados en yogurt durante su almacenamiento. En tres ocasiones diferentes, dos distintas marcas comerciales de yogurt, una con probióticos adicionales (Lactobacillus casei y L. acidophilus) fueron inoculadas con una población conocida (10(6) UFC/g) de L. monocytogenes o E. coli O157: H7 y almacenadas a 5ºC por 32 días. Cada cuatro días se realizó un recuento de bacterias lácticas, de los patógenos agregados y se determinó el pH, de acuerdo a la metodología descrita en el Bacteriological Analytical Manual. El número de bacterias lácticas y el pH se mantuvieron constantes durante el período de evaluación. El yogurt con probióticos adicionales redujo la población de L. monocytogenes a niveles no detectables en 8 días de almacenamiento, la población de E. coli O157:H7 en 16 días; el yogurt sin probióticos adicionales tardó 20 días en reducir la población de L. monocytogenes a niveles no detectables y aún después de 28 días de almacenamiento, se pudo cultivar la E. coli O157:H7. En este trabajo, se confirma de nuevo los efectos beneficiosos de los cultivos probióticos adicionales en yogurt.Evaluation of the effect of probiotic cultures added to commercial yogurt over a known population of Listeria monocytogenes and Escherichia coli O157:H7. The effect of probiotic cultures over Listeria monocytogenes and Escherichia coli O157:H7 during yogurt storage was evaluated. Two different yogurt brands, one with additional probiotic cultures (Lactobacillus casei and L. acidophilus) were inoculated with known populations (10(6) UFC/g) of either L. monocytogenes or E. coli O157:H7 in three different times and stored for 32 days at 5ºC. Every four days the count of lactic bacteria, the added pathogens and pH was evaluated, according to the methodology described in the Bacteriological Analytical Manual. The pH and lactic bacteria population were constant during the testing period. Yogurt with additional probiotic cultures reduced the population of L. monocytogenes in 8 days, the population of E. coli O157:H7 in 16; yogurt with no additional probiotics took 20 days to reduce L. monocytogenes to non-detectable levels and even after 28 days of storage, E. coli O157:H7 was cultured. In this work, the beneficial effects of additional probiotic cultures in yogurt is confirmed again.

[Display omitted] • In-situ growth of nitrogen-doped carbonized polymer dots on few-layer black phosphorus nanosheets was realized. • The 0D-2D heterostructure of this composite was proved. • A portable intelligent electrochemical DNA biosensor for detecting Escherichia coli O157: H7 sequence was established. Sensitive and accurate detection technology for pathogenic bacteria is of great social and economic significance in foodborne disease and food safety. In this paper, a novel portable electrochemical DNA biosensor for the detection of specific DNA sequence of Escherichia coli (E. coli) O157: H7 was constructed. To enhance the performance of the electrochemical sensor, a functionalized nitrogen-doped carbonized polymer dots in-situ grown on few-layer black phosphorus (N-CPDs@FLBP) was synthesized and used as the modifier on the surface of screen-printed electrode. Combining gold nanoparticles as immobilization matrix and methylene blue as electrochemical indicator, the analytical performance of this electrochemical DNA biosensor was evaluated using standard complementary ssDNA sequence in the linear concentration range from 1.0 × 10−19 to 1.0 × 10−6 mol/L with a low detection limit as 3.33 × 10−20 mol/L (3 σ). Furthermore, the portable electrochemical DNA biosensor was proposed based on polymerase chain reaction amplification for the detection of the E. coli O157: H7 genomic DNA from chicken meat, which verified the feasibility for practical samples detection. The research has great theoretical and practical significance for the development of electrochemical biosensor of pathogenic bacteria. [ABSTRACT FROM AUTHOR]

In the last 20 years Escherichia coli O157: H7 has emerged as a new pathogen, causing worldwide disease, death and economic loss. Different studies have revealed important survival characteristics of this pathogen, although there are divergent criteria about its ability to survive in various mayonnaise formulations. We studied the effect of different mayonnaise concentrations (0 %, 18 %, 37 % and 56 %) (weight/weight) over the survival of the bacterium in common foods from a neotropical environment (Costa Rica). High [10 7 -10 8 Colony Forming Units (CFU)/ml] and low E. coli populations (10 4 -10 6 CFU/ml) were inoculated, (three replicates) in meat, chopped cabbage and poultry, and mixed with commercial mayonnaise to obtain the concentrations specified. They were incubated at 12 ºC for 24, 48 and 72 hr. The E. coli O157: H7 enumeration was done according to a standard methodology. Populations of E. coli O157: H7 showed an increasing trend during the first incubation period (48 hr), in all the preparations, regardless of the fat concentration used. Our data indicate that E. coli O157: H7 is capable of surviving and growing in meat, cabbage and poultry mixed with mayonnaise, independently of its concentrationEn los últimos 20 años, Escherichia coli O157: H7 ha emergido como un nuevo patógeno, causando enfermedad, muerte y pérdidas económicas mundialmente. Diversos estudios han revelado que este patógeno posee importantes características de sobrevivencia, no obstante, existe criterio divergente respecto a su habilidad para sobrevivir en varias formulaciones basadas en mayonesa. Se procedió a estudiar el efecto de diversas concentraciones de mayonesa (0 %, 18 %, 37 % y 56 %) (p/p) en la sobrevivencia de la bacteria en alimentos comunes de un ambiente neotropical (Costa Rica). Una población alta de E. coli (10 7 -10 8 UFC/ml) y una baja (10 4 -10 6 UFC/ml) fueron inoculadas, en tres ocasiones diferentes, en carne picada, repollo picado y pollo picado y mezcladas con mayonesa comercial, con el fin de obtener las concentraciones estipuladas. Estas muestras fueron incubadas a 12 ºC por 24, 48 y 72 hr. La enumeración de E. coli O157: H7 se realizó de acuerdo a la metodología descrita en el Bacteriological Analytical Manual. Las poblaciones de E. coli mostraron una tendencia a aumentar durante las primeras horas de incubación (48 hr) a pesar de las concentraciones de grasa utilizadas. Los hallazgos de este estudio indican que la E. coli O157: H7 es capaz de sobrevivir y crecer en ensaladas de carne, repollo, y pollo. Se debe tener precaución para evitar el falso sentimiento de seguridad derivado del uso de mayonesa en ensaladas

A rapid pretreatment-free immunochromatographic assay (ICA) was developed for the screen of Escherichia coli O157:H7 (E. coli O157:H7) in bovine milk. Anti-E. coli O157:H7 immunoglobins of yolk (IgY) was conjugated with a core/shell-structured super-paramagnetic Fe3O4/Au composite nanoparticle (GoldMag) and showed a high coupling ratio of 8 ²g IgY mL-1 nanoparticles at pH 8.0. The conditions of ICA strips using this IgY conjugate were optimized and could be used to measure spiked E. coli O157:H7 samples with a detection limit of 10³CFU mL-1 obtained by visual detection. Additionally, the magnetic signal intensities of the assay can quantitatively measure E. coli O157:H7 concentration in the range of 10² -105 CFU mL-1 both in phosphate buffer solution (pH 7.4) and pretreatment-free milk samples with a detection limit of 10² CFU mL-1. [ABSTRACT FROM AUTHOR]

Preservative and antibacterial effects of citric acid and lactic acid treated beef were studied previously on Escherichia coli O157: H7 and Salmonella typhymurium. This was aimed to investigate the effects of these acids on the total viable count (TVC) of these bacteria. Three diluted concentrations (1.0, 3.0 and 5.0%) of both citric acid and lactic acid were used. A total of 3024 meat samples were collected from cattle slaughtered at Peshawar, Pakistan. Samples were processed and analyzed for TVC of E. coli and S. typhymurium at 0, 48, 144 and 288hrs during 12 days of meat samples refrigeration storage at 4±1 °C. The pH of meat samples were checked and recorded on similar intervals. During 12 days storage, significant reductions (i.e. P <0.05) were found in both E. coli O157: H7 and S. typhymurium growth when exposed to these treatments. Results revealed that levels of citric and lactic acid concentrations effect were maximum for 5.0%, followed by 3.0% and least for 1.0% on E. coli and Salmonella load on beef surfaces. In addition, citric acid was more effective than lactic acid at all concentrations (1.0, 3.0 and 5.0%) in reducing E. coli and Salmonella growth. The citric acid at 5.0% was found significantly effective treatment in reducing E. coli O157: H7 and S. typhymurium population on beef stored samples. [ABSTRACT FROM AUTHOR]

Escherichia coli O157:H7 is a predominant foodborne pathogen with severe pathogenicity, leading to increasing attention given to rapid and sensitive detection. Herein, we propose an impedance biosensor using new kinds of screen-printed interdigitated microelectrodes (SPIMs) and wheat germ agglutinin (WGA) for signal amplification to detect E. coli O157:H7 with high sensitivity and time-efficiency. The SPIMs integrate the high sensitivity and short response time of the interdigitated electrodes and the low cost of the screen-printed electrodes. Self-assembling of bi-functional 3-dithiobis-(sulfosuccinimidyl-propionate) (DTSP) on the SPIMs was investigated and was proved to be able to improve adsorption quantity and stability of biomaterials. WGA was further adopted to enhance the signal taking advantage of the abundant lectin-binding sites on the bacteria surface. The immunosensor exhibited a detection limit of 10² cfu⋅mL-1, with a linear detection range from 10² to 107 cfu⋅mL-1 (r² = 0.98). The total detection time was less than 1 h, showing its comparable sensitivity and rapid response. Furthermore, the low cost of one SPIM significantly reduced the detection cost of the biosensor. The biosensor may have great promise in food safety analysis and lead to a portable biosensing system for routine monitoring of foodborne pathogens. [ABSTRACT FROM AUTHOR]

Both sprouts and microgreens are popular tender produce items, typically grown and harvested in indoor facilities which allow a higher degree of control compared to open field production. While sprouts, which have frequently been implicated in foodborne illness outbreaks, are the subject of numerous national and international standards for their production and distribution, there is a lack of data pertaining to the microbiological safety of microgreens. In this study, sprouts and microgreens were produced from radish seeds inoculated with Escherichia coli O157: H7 or O104: H4 and E. coli populations on the harvested products compared to assess the potentials of product contamination from contaminated seeds during sprouting and microgreen production. Both E. coli O157:H7 and O104:H4 grew rapidly during sprouting, reaching levels of 5.8-8.1 log cfu/g and 5.2-7.3 log cfu/g, respectively, depending on the initial inoculation levels of the seeds (1.5-4.6 log cfu/g and 0.8-4.3 log cfu/g on radish seeds, respectively). In comparison, E. coli O157:H7 and O104:H4 populations on harvested microgreens ranged from 0.8 to 4.5 log cfu/g and from 0.6 to 4.0 log cfu/g, respectively. Although harvested microgreens carried significantly less (P < 0.001) E. coli than sprouts germinated from seeds inoculated at the same levels, proliferation of E. coli O157:H7 and O104:H4 occurred during both sprouting and microgreen growth. [ABSTRACT FROM AUTHOR]

The goal of our study was to use spatial scan statics to determine whether the night roosts of European starlings ( Sturnus vulgaris) act as point sources for the dissemination of Escherichia coli O157: H7 among dairy farms. From 2007 to 2009, we collected bovine faecal samples ( n = 9000) and starling gastrointestinal contents ( n = 430) from 150 dairy farms in northeastern Ohio, USA. Isolates of E. coli O157: H7 recovered from these samples were subtyped using multilocus variable-number tandem repeat analysis ( MLVA). Generated MLVA types were used to construct a dendrogram based on a categorical multistate coefficient and unweighted pair-group method with arithmetic mean ( UPGMA). Using a focused spatial scan statistic, we identified statistically significant spatial clusters among dairy farms surrounding starling night roosts, with an increased prevalence of E. coli O157: H7-positive bovine faecal pats, increased diversity of distinguishable MLVA types and a greater number of isolates with MLVA types from bovine-starling clades versus bovine-only clades. Thus, our findings are compatible with the hypothesis that starlings have a role in the dissemination of E. coli O157: H7 among dairy farms, and further research into starling management is warranted. [ABSTRACT FROM AUTHOR]

The present study was conducted to investigate the presence of Escherichia coli O157: H7 in food samples of animal origin and to detect its virulence genes by immunomagnetic separation technique and multiplex PCR ( mPCR). A total of 500 samples (consisting of diced meat, minced meat, burger, raw cow's milk and raw cow's milk cheese) were analysed. Escherichia coli O157: H7 was detected in 5 (1%) of 500 analysed samples including two diced meat, one minced meat and two raw-milk cheese. None of the burger samples tested contained E. coli O157: H7. Three isolates obtained from minced and diced meat were found to carry stx 1, stx 2, hlyA and eaeA genes whereas two isolates from raw-milk cheese were found to harbour the stx 1, eaeA and hlyA genes. The results of this study suggest that raw meat and raw-milk cheese tested could pose public health problems in consumers with regard to their virulence factors. Significance and Impact of the Study Escherichia coli ( E. coli) O157:H7 is an important human pathogen. Escherichia coli 0157:H7 infections have been associated with consumption of uncooked meat and meat products, as well as unpasteurized dairy products. This study demonstrated that without specific tests for E. coli virulence factors raw meat and raw-milk cheese could pose public health problems to Turkish consumers. [ABSTRACT FROM AUTHOR]

Salad vegetables contaminated with pathogens can cause food poisoning. The isolation of Escherichia coli O157:H7 and Listeria monocytogenes from different salad vegetables; cucumber, cabbage, carrot, and lettuce was carried out. E. coli O157:H7 was isolated from all the salad vegetables while L. monocytogenes was isolated from only cabbage and lettuce. The effect of different storage temperatures on the survival and growth of E. coli O157:H7 and L. monocytogenes on cabbage and lettuce was determined. Known population of each isolate was inoculated into sliced cabbage and lettuce separately and stored at 5°C (refrigerator temperature) and 28°C (room temperature) for 10 days. Bacteria were counted on daily basis. Result showed initial increase in most cases on second and/or third day followed by decrease in bacterial population all through storage. There was no growth towards the end of storage at 28°C. In all cases there was decrease in pH. The count of E. coli O157:H7 ranged from 3.6x10³ -4.0 x 10² cfu/g in salad vegetables stored at 5°C and the pH, 7.11 - 5.66 while the count at 28°C was 3.9 x 10³ - 1.0x 10² cfu/g with pH 7.11 -4.06. L. monocytogenes count in salad vegetables stored at 5°C was 1.51x104 - 4.8x10² cfu/g and pH was 7.12 - 5.84. At 28°C, the count was 1.49 x 104 - 2.0 x 102 cfu/g and pH was 7.14-4.14. Both bacterial pathogens survived at storage temperatures at which salad vegetables are normally stored in practice. Their presence and survival in salad vegetables call for public health concern because salad vegetables receive little or no heat treatment before consumption. [ABSTRACT FROM AUTHOR]

In this study, extracts and essential oils of Black and Red pepper and Thyme were tested for antibacterial activity against Escherichia coli O157: H7 and Staphylococcus aureus. Black and Red pepper and Thyme were provided from Iranian agricultural researches center. 2 g of each plant powder was added to 10 cc ethanol 96°. After 24 h, the crude extract was separated as an alcoholic extract and concentrated by distillation method. Plants were examined for determining their major component and essential oils were separated. Phytochemical analyses were done for detection of some effective substances in extracts. The antibacterial activity against Escherichia coli O157: H7 and Staphylococcus aureus was tested and the results showed that all extracts and essential oils were effective and essential oils were more active. The extracts and oils that showed antimicrobial activity were later tested to determine the Minimum Inhibitory Dilution (MID) for those bacteria. They were also effective on the inhibition of DNase activity. This study was indicated that extracts and essential oils of Black and Red pepper and Thyme can play a significant role in inhibition of Escherichia coli O157: H7 and Staphylococcus aureus. [ABSTRACT FROM AUTHOR]

Since its first description in 1982, the zoonotic life-threatening Shiga toxin-producing Escherichia coli O157: H7 has emerged as an important food- and water-borne pathogen that causes diarrhea, hemorrhagic colitis, and hemolytic-uremic syndrome in humans. In the last decade, increases in E. coli O157: H7 outbreaks were associated with environmental contamination in water and through fresh produce such as green leaves or vegetables. Both intrinsic (genetic adaptation) and extrinsic factors may contribute and help E. coli O157: H7 to survive in adverse environments. This makes it even more difficult to detect and monitor food and water safety for public health surveillance. E. coli O157: H7 has evolved in behaviors and strategies to persist in the environment. [ABSTRACT FROM AUTHOR]

The aim of this study was to examine the effect of the bovine milk fat globule membrane (MFGM) on the virulence of Escherichia coli O157:H7. The MFGM was extracted from raw or heat-treated milk, resulting in 2 preparations differing in protein composition. Both heated and raw MFGM exerted an inhibitory effect on Shiga toxin gene expression by E. coli O157:H7 (ratios of -7.69 and -5.96, respectively). Interestingly, the effect was stronger with heated MFGM, with a larger decrease in expression of the virulence gene fliC (ratio of -9.43). The difference in effect observed between heated and raw MFGM could be explained by the difference in protein composition between the 2 preparations. These results show, for the first time, a specific effect of MFGM on expression of Shiga toxin genes as well as genes involved in the motility of E. coli O157:H7. This may offer a new approach to mitigate the adverse health effects caused by E. coli O157:H7 infections. [ABSTRACT FROM AUTHOR]

Abstract: The main goal of this investigation was to study the efficacy of X-ray doses (0.1, 0.2, 0.3, 0.5, 0.75, 1.0, 1.5 and 2.0 kGy) on inoculated Escherichia coli O157: H7, Listeria monocytogenes, Salmonella enterica and Shigella flexneri on shredded iceberg lettuce. The second goal was to study the effect of X-ray on the inherent microflora counts and visual color of shredded iceberg lettuce during storage at 4 °C for 30 days. Treatment with 1.0 kGy X-ray significantly reduced the population of E. coli O157: H7, L. monocytogenes, Salmonella enterica and S. flexneri on shredded iceberg lettuce by 4.4, 4.1, 4.8 and 4.4-log CFU 5 cm−2, respectively. Furthermore, more than a 5 log CFU reduction of E. coli O157: H7, L. monocytogenes, S. enterica and S. flexneri was achieved with 2.0 kGy X-ray. Treatment with X-ray reduced the initial microflora on iceberg lettuce and kept them significantly (p < 0.05) lower than the control during storage at 4 °C and 90% RH for 30 days. Treatment with X-ray did not significantly (p > 0.05) change the green color of iceberg lettuce leaves. Treatment with X-ray significantly reduced selected pathogens and inherent microorganisms on shredded iceberg lettuce leaves, which could be a good alternative to other technologies for produce (lettuce) industry. [Copyright &y& Elsevier]

Bacterial resistance to antibiotics is enhanced by unrestricted use of such drugs. In addition, stimulating effects of certain antibiotics on the production of verocytotoxin by enterohemorrhagic Escherichia coli have been reported. The aim of this communication was to report a medicinal plant species that is effective against a broad range of bacteria of clinical importance including Acinetobacter baumannii, Bacillus cereus, Enterobacter faecalis, Escherichia coli, Helicobacter pylori, Klebsiella pneumoniae, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella spp., Shigella flexneri, Staphylococcus aureus, Streptococcus mutans, and Streptococcus pyogenes. Ethanol extracts of Quercus infectoria Oliv. (Fagaceae) demonstrate a broad spectrum of activity against all bacterial species tested. Detailed studies were carried out on clinical isolates of pathogens commonly presenting problems with the use of antibiotics, including enterohemorrhagic Escherichia coli (EHEC), methicillin-resistant Staphylococcus aureus (MRSA), multidrug-resistant Klebsiella pneumoniae, multidrug-resistant Helicobacter pylori, and Salmonellaspp. The extracts of Quercus infectoria displayed remarkable activity against MRSA with MICs ranging from 0.02 to 0.4 mg/mL, and MBCs ranging from 0.4 to 1.6 mg/mL. More importantly, this plant species could exhibit strong antibacterial activity against all Gram-Negative organisms. Its significant activity was shown with EHEC, with MICs of 0.05 to 0.1 mg/mL and MBCs of 0.8 to 1.6 mg/mL. The results from this study indicate that Quercus infectoria is potentially a good source of antibacterial substances with broad spectrum of activities against antibiotic-resistant bacteria. [ABSTRACT FROM AUTHOR]

Aims: The objective was to investigate the occurrence of sublethal injury after pulsed electric field (PEF) depending on the treatment time, the electric field strength and the pH of the treatment media in two Gram-positive (Bacillus subtilis ssp. niger, Listeria monocytogenes) and six Gram-negative (Escherichia coil, Escherichia coil O157:H7, Pseudomonas aeruginosa, Salmonella serotype Senftenberg 775W, Salmonella serotype Typhimurium, Yersinia enterocolitica) bacterial strains. Methods and Results: A characteristic behaviour was observed for the Gram-positive and Gram-negative bacteria studied. Whereas Gram-positive bacteria showed a higher PEF resistance at pH 7·0, the Gram-negative were more resistant at pH 4·0. In these conditions, in which bacteria showed their maximum resistance, a large proportion of sublethally injured cells were detected. In most cases, the longer the treatment time and the higher the electric field applied, the greater the proportion of sublethally injured cells that were detected. No sublethal injury was detected when Gram-positive bacteria were treated at pH 4·0 and Gram-negative at pH 7·0. Conclusions: Sublethal injury was detected after PEF so, bacterial inactivation by PEF is not an 'all or nothing' event. Significance and Impact of the Study: This work could be useful for improving food preservation by PEF. [ABSTRACT FROM AUTHOR]

Rejuvenated cells of Escherichia coli O157: H7 (105 cfu/ml) were frozen in a commercial vegetable broth and stored (−18 °C) for up to 168 h. The pathogen was recovered and enumerated on three bacteriological media. A selective medium (Violet Red Bile Agar or VRBA), a non-selective medium (Plate Count Agar or PCA) and a solid-repair medium (overlaid VRBA on surface plated-PCA) were used. Frozen storage for 24 and 168 h reduced the viable population (Vp) of the pathogen by 56% (P<0.05) and 96% (P<0.01) and damaged about 22% (P<0.05) and 45% (P<0.01) of the survivors, respectively. The average rate of change of the Vp and the non-damaged population (NDp) of E. coli O157: H7 was about 12% and 10% of the respective rate of change for the first 24 h of frozen storage. The solid-repair medium increased the recovery of the pathogen throughout the frozen storage period. An analysis of variance showed that frozen storage significantly (P=0.01) decreased cell recovery. A series of paired t-tests indicated that media not always affected cell recovery (P&les;0.05). [Copyright &y& Elsevier]