Growth and Survival of Acid-Resistant and Non-Acid-Resistant Shiga-Toxin-Producing Escherichia coli Strains during the Manufacture and Ripening of Camembert Cheese.

Growth and survival of acid-resistant (AR) and non-acid-resistant (NAR) Shiga-toxin-producing Escherichia coli (STEC) strains were investigated during the manufacture and ripening of microfiltered milk Camembert cheeses. The induction of acid resistance of the STEC strains in cheeses was also studied. Six different mixtures of AR and/or NAR STEC strains were inoculated separately into microfiltered milk at a level of 10(3) CFU mL(-1).

Fate of acid-resistant and non-acid resistant Shiga toxin-producing Escherichia coli strains in experimentally contaminated French fermented raw meat sausages.

Both pathogenic and nonpathogenic E. coli exhibit a stress response to sublethal environmental stresses. Several studies have reported acid tolerance and survival characteristics of E.

Community-wide outbreak of Escherichia coli O157:H7 associated with consumption of frozen beef burgers.

On 24-25 October 2005 a cluster of five haemolytic uraemic syndrome (HUS) cases was reported in southwest France. An investigation was undertaken to identify the outbreak source and implement control measures. Cases were defined as individuals with HUS or diarrhoea with isolation of Escherichia coli O157:H7 in stools or a positive antibody response to E.

Growth of Shiga-toxin producing Escherichia coli (STEC) and bovine feces background microflora in various enrichment protocols.

Cattle are an important reservoir for STEC and eating food contaminated with fecal material is a frequent source of human STEC infection. It is thus essential to reliably determine the prevalence of STEC contamination in cattle. Currently, different enrichment protocols are used before the detection of Shiga-Toxin producing Escherichia coli (STEC) in fecal samples.

O148 Shiga toxin-producing Escherichia coli outbreak: microbiological investigation as a useful complement to epidemiological investigation.

An outbreak of Shiga toxin-producing Escherichia coli (STEC) O148 infection occurred among wedding attendees in France in June 2002. A retrospective cohort study was performed and ten cases were identified, including two adults with haemolytic uraemic syndrome (HUS). The analytical study revealed that > 80% of affected individuals had eaten lightly roasted mutton and poultry pâté, but only the consumption of pâté tended to be associated with illness (relative risk 3.

First isolation of Shiga toxin 1d producing Escherichia coli variant strains in shellfish from coastal areas in France.

Aims: This study was carried out to evaluate the presence of Shiga toxin-producing Escherichia coli (STEC) and E. coli O157:H7 in shellfish from French coastal environments.

Methods And Results: Shellfish were collected in six growing areas or natural beds (B category) and nonfarming areas (D category) from July 2002 to August 2004.

Modeling and predicting the simultaneous growth of Escherichia coli O157:H7 and ground beef background microflora for various enrichment protocols.

The simultaneous growth of Escherichia coli O157:H7 (O157) and the ground beef background microflora (BM) was described in order to characterize the effects of enrichment factors on the growth of these organisms. The different enrichment factors studied were basal medium (Trypticase soy broth and E. coli broth), the presence of novobiocin in the broth, and the incubation temperature (37 degrees C or 40 degrees C).

Isolation and characterization of Shiga toxin-producing Escherichia coli strains from raw milk cheeses in France.

Aims: To evaluate Shiga toxin-producing Eschericha coli (STEC) prevalence in 1039 French raw milk cheeses including soft, hard, unripened and blue mould cheeses, and to characterize the STEC strains isolated (virulence genes and serotypes).

Methods And Results: STEC strains were recovered from cheese samples by colony hybridization. These strains were then serotyped and genetically characterized.

Growth and survival of Escherichia coli O157:H7 during the manufacture and ripening of raw goat milk lactic cheeses.

The behaviour of Escherichia coli O157:H7 was studied during the manufacture and ripening of raw goat milk lactic cheeses. Cheese was manufactured from raw milk in the laboratory and inoculated with E. coli O157:H7 to a final concentration of 10, 100 and 1000 cfu ml(-1).

Serotyping, stx2 subtyping, and characterization of the locus of enterocyte effacement island of shiga toxin-producing Escherichia coli and E. coli O157:H7 strains isolated from the environment in France.

Twenty-seven Shiga toxin-producing Escherichia coli (STEC) strains were isolated from 207 stx-positive French environmental samples. Ten of these strains were positive for stx(1), and 24 were positive for stx(2) (10 were positive for stx(2vh-a) or stx(2vh-b), 19 were positive for stx(2d), and 15 were positive for stx(2e)). One strain belonged to serotype O157:H7, and the others belonged to serogroups O2, O8, O11, O26, O76, O103, O113, O121, O141, O166, and O174.

Prevalence of verotoxin-producing Escherichia coli (VTEC) in slurry, farmyard manure and sewage sludge in France.

Aims: The aims of the present study were to determine VTEC prevalence in manure, slurry and sewage sludge in France and to characterize the VTEC strains isolated (virulence genes and serotype).

Methods And Results: Seven hundred and fifty-two samples from 55 farmyard manures, 136 bovine and porcine faeces, 114 slurries, 10 composts, and 437 samples from outflows of sewage wastewater treatment plants were analysed. Twenty-four percent contained isolates which were PCR positive for stx gene.

Prevalence of Escherichia coli O157:H7 in industrial minced beef.

Aims: The lack of baseline data on the prevalence of Escherichia coli O157:H7 in retail minced beef in France prompted this survey of industrial minced beef production.

Methods And Results: An automated enzyme-linked fluorescence immunoassay (ELFA), the VIDAS E. coli O157 method, was used to detect E.

Effects of slaughter processes on pig carcass contamination by verotoxin-producing Escherichia coli and E. coli O157:H7.

The aims of the present study were: (i) to evaluate verotoxin-producing Escherichia coli (VTEC) faecal carriage of slaughtered pigs; (ii) to determine the effects of three different pig slaughtering processes on pig carcass contamination by VTEC; (iii) to characterise the VTEC strains isolated from pig and pig slaughterhouses (virulence genes and serotype); and (iv) to compare the strains isolated in the same slaughterhouse in order to identify the routes of contamination inside the slaughterhouse. Pork carcasses from three French slaughterhouses were sampled at three steps of the slaughter process and different sites in each slaughterhouse were sampled at three different times in the work day. Faecal material from each sampled carcass, potable water and scalding water were also collected.

Effects of cutting process on pork meat contamination by verotoxin-producing Escherichia coli (VTEC) and E. coli O157:H7.

The aims of the present study were: (i) to evaluate verotoxin-producing Escherichia coli (VTEC) prevalence in pork cutting meat; (ii) to determine the effects of cutting process on pork meat contamination by VTEC; (iii) to characterise the VTEC strains isolated from pork and pork cutting plants (virulence genes and serotype); and (iv) to compare the strains isolated the same day in the same cutting plant in order to identify the routes of contamination inside the cutting plant. Pork carcasses from three French cutting plants were sampled before carcass cutting (carcass samples), after carcasses were divided into big portions (untrimmed cuts) and after preparation of primal cuts (rindless boneless cuts), and different environmental sites in each cutting plant were sampled at three different times in the work day. Potable water was also collected.

Prevalence of verotoxin-producing Escherichia coli (VTEC) and E. coli O157:H7 in French pork.

Aims: To determination the prevalence of VTEC in pork products and the surrounding environment of the pork plant (slaughterhouse and cutting plant), and characterization of the VTEC strains isolated (virulence genes and serotype).

Methods And Results: Among the 2146 carcass and pork samples and 876 environmental samples (swabs of surfaces or materials), 328 (15%) and 170 (19%) were PCR-positive for stx genes respectively. VTEC strains were recovered from positive samples by colony hybridization or immunoconcentration, serotyped and genetically characterized.

Prevalence of verotoxin-producing Escherichia coli and E. coli O157:H7 in pig carcasses from three French slaughterhouses.

Verotoxin-producing Escherichia coli (VTEC) are important food-borne pathogens in humans. Several studies have demonstrated that cattle are a major reservoir of VTEC but few data are available about the occurrence of VTEC in other species. In France, there is no data about pigs and pork meat.

Detection of Escherichia coli O157:H7 in heifers' faecal samples using an automated immunoconcentration system.

Pre-treatment of a 5-h enrichment culture with an automated immunoconcentration (ICE) system greatly improved the isolation of Escherichia coli O157:H7 from spiked heifer faecal samples. Enrichment samples plated directly onto sorbitol MacConkey agar (SMAC) and SMAC agar supplemented with cefixime and potassium tellurite (CT-SMAC) showed recovery rates of 8% and 56%, respectively. However, after ICE treatment, E.

An automated method for the detection of staphylococcal heat stable deoxyribonuclease in dairy products.

An automated sandwich immunoassay with specific polyclonal antibodies for the detection of Staphylococcus aureus thermostable nuclease (DNase) is described. To evaluate this assay, different quantities of purified S. aureus nuclease were added to dairy products.

Evaluation of an alternative extraction procedure for enterotoxin determination in dairy products.

A concentration protocol based on trichloroacetic acid precipitation was evaluated and compared with the reference method using dialysis concentration. Different quantities of purified staphylococcal enterotoxins were added to pasteurized Camembert-type cheeses. Detection of enterotoxins in these cheeses was performed using an automated detection system.