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Article

G.D. Betts

Escherichia coli O157 is a virulent food pathogen that can cause severe illness in humans. The number of cases is steadily rising and reached over 1,000 in 1999. Foods…

Abstract

Escherichia coli O157 is a virulent food pathogen that can cause severe illness in humans. The number of cases is steadily rising and reached over 1,000 in 1999. Foods associated with E. coli O157 are primarily meat and meat products, but other foods have been implicated, including cheese, lettuce and fruit products. A particular problem for food manufacturers is that this organism may survive in acidic products, for example, fermented meats, apple juice and mayonnaise. Studies were done to evaluate the growth and survival of E. coli O157 in acid environments. It was shown that this organism could grow at a pH of 3.75 and could survive for seven days at pH 3.3 and six hours at pH 2.8 in the presence of 3 per cent (v/v) acetic acid. These data are of use to manufacturers of acid products to control the growth and survival of E. coli O157.

Details

Nutrition & Food Science, vol. 30 no. 4
Type: Research Article
ISSN: 0034-6659

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Abstract

Purpose

Broad-spectrum cephalosporin resistance is rapidly increasing in Escherichia coli, representing a food safety problem. The purpose of this paper is to characterize eight extended-spectrum-ß-lactamase (ESBL) and acquired AmpC ß-lactamase-producing E. coli isolates and virotypes associated, obtained from chicken and pork food samples in Puebla, Mexico.

Design/methodology/approach

Samples (36 from chicken and 10 from pork) were cultured on Levine agar plates supplemented with cefotaxime (2 mg/L) for isolation of cefotaxime-resistant (CTXR) E. coli. CTXR-E. coli isolates were detected in 33 of 46 samples (72 percent), and one isolate/sample was characterized (28 from chicken and 5 from pork), for ESBL production, phylogenetic group, sequence typing, resistance and virulence genes by PCR and sequencing.

Findings

Results showed 16 ESBL-E. coli (35 percent) (12/16 belonging to phylogroup B1) and 8 CMY-2-E. coli (17 percent). ESBL detected were as follows (number of isolates): CTX-M-2 (8); CTX-M-1 (2); CTX-M-15 (1); SHV-2a (4) and TEM-52c (1). In total, 20 different sequence types (STs) were identified among the ESBL- or CMY-2-producing E. coli strains, which included four new ones. The CTX-M-15 β-lactamase was detected in one E. coli ST617-ST10 Cplx-B1 strain that also carried ibeA gene. One CMY-2-positive strain of lineage ST224-B2 was detected and it carried the qnrA1 gene.

Originality/value

In this study, a ST131-based virotyping scheme for strains from food of animal origin was established since this kind of strains constitutes an important vehicle of virulent ESBL- and CMY-2-producing E. coli isolates, which could be transmitted to humans by direct contact or through the food chain.

Details

British Food Journal, vol. 120 no. 7
Type: Research Article
ISSN: 0007-070X

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Article

Kaotar Nayme, Abouddihaj Barguigua, Brahim Bouchrif, Idrissa Diawara, Fatima El Otmani, Naima Elmdaghri, Khalid Zerouali and Mohammed Timinouni

The purpose of this paper is to assess the occurrence of the extended-spectrum β-lactamases (ESBLs) and AmpC β-lactamase genes in 144 Escherichia coli isolates recovered…

Abstract

Purpose

The purpose of this paper is to assess the occurrence of the extended-spectrum β-lactamases (ESBLs) and AmpC β-lactamase genes in 144 Escherichia coli isolates recovered from 160 vegetable salad samples.

Design/methodology/approach

Among the 144 E. coli isolates recovered from 160 vegetable salads, 17 (12 percent) ceftazidime-resistant isolates were screened for ESBL production with the double disk-diffusion test. The ESBL-producing isolates were characterized for antimicrobial resistance, the presence of virulence genes and plasmid-mediated quinolone resistance (PMQR) determinants. The isolates were also subjected to phylogenetic group typing. The existence of plasmid AmpC genes and mutations in the regulatory region of the chromosomal AmpC gene was assessed using polymerase chain reaction (PCR) and sequencing. All β-lactamase isolates were further characterized by pulsed-field gel electrophoresis to determine the genetic relatedness.

Findings

Overall, 17 (12 percent) of the 144 E. coli isolates studied were ceftazidime resistant. Among the 17 isolates, 13 (77 percent) were multidrug resistant and four (23.5 percent) were ESBL producers. The bla CTX-M14 was the only gene detected. Of the 12 AmpC-producing isolates, three (18 percent) harbored plasmid-encoded AmpC and sequencing analysis of the chromosomal AmpC genes revealed mutations in the promoter/attenuator region. PMQR determinants were detected in 9 (52 percent) isolates. A was the most prevalent phylogenetic group (56 percent), followed by groups B1 (31 percent), D (6 percent), and B2 (6 percent). PCR showed that six (50 percent) ESBL/AmpC-producing E. coli isolates carried one and/or two virulence genes. Pulsed-field gel electrophoresis showed no epidemiological relationship between these isolates.

Originality/value

This study places vegetable salads within the spectrum of ecological niches that may be vehicles for antibiotic-resistant bacteria/genes with clinical interest and these findings are worthy of attention as their spread to humans by ingestion cannot be dismissed.

Details

British Food Journal, vol. 119 no. 7
Type: Research Article
ISSN: 0007-070X

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Article

Evelyne Toe, Adjéhi Dadié, Etienne Dako, Guillaume Loukou, Marcelin Koffi Dje and Y.C. Blé

Vegetable salads, despite their recognized health benefits, are an increasingly common cause of foodborne illness worldwide. The purpose of this paper is to determine the…

Abstract

Purpose

Vegetable salads, despite their recognized health benefits, are an increasingly common cause of foodborne illness worldwide. The purpose of this paper is to determine the prevalence of E. coli with virulence genes in ready-to-eat raw mixed vegetable salads sold in collective catering in Abidjan.

Design/methodology/approach

A total of 436 strains of E. coli were isolated from 306 ready-to-eat raw mixed vegetables salads and then identified biochemically and molecularly based on the uidA gene responsible for beta-glucuronidase activity. The virulence genes were determined by polymerase chain reaction.

Findings

The prevalence in vegetable salads of E. coli with virulence genes was 35.3 percent. The distribution of pathovars was 21.2 percent enterotoxigenic (ETEC), 4.9 percent enteropathogenic (EPEC), 0.7 percent Shigatoxigenic (STEC), and 7.5 percent Enteroaggregative E. coli (EAEC). It appears from the study that vegetable salads sold in collective catering in Abidjan are at risk for contamination by E. coli pathovars.

Originality/value

Processing conditions for these salads during preparation appear to be hygienically insufficient, so measures to control the risk of contamination are necessary.

Details

British Food Journal, vol. 120 no. 12
Type: Research Article
ISSN: 0007-070X

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Article

Larry R. Beuchat

Food and water safety is a major international concern. Among the food groups implicated with greater frequency in recent years as having caused or been associated with…

Abstract

Purpose

Food and water safety is a major international concern. Among the food groups implicated with greater frequency in recent years as having caused or been associated with enteric diseases in humans are raw fruits and vegetables. Outbreaks of diseases caused by infectious and toxigenic bacteria as well as parasites and viruses have been documented to occur as a result of consumption of contaminated produce. This paper seeks to review the scientific literature reporting evidence to support the potential for preharvest contamination of fruits and vegetables intended to be eaten raw.

Design/methodology/approach

Sources of preharvest contamination of produce include manure, manure compost, sewage sludge, irrigation water, runoff water from livestock operations, and wild and domestic animals. Literature was reviewed to assess the conditions affecting survival of pathogenic microorganisms originating from these sources in preharvest environments and potential for contamination of produce before or at the time of harvest.

Findings

Prevention of preharvest contamination is essential to minimizing the risk of illness caused by consuming raw produce because postharvest treatment with sanitizers cannot be relied upon to eliminate pathogens.

Originality/value

A better understanding of the behaviour of pathogens in preharvest environments will enhance the prospect of developing effective strategies and interventions that will assure the delivery of safe produce to the consumer.

Details

British Food Journal, vol. 108 no. 1
Type: Research Article
ISSN: 0007-070X

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Article

Adrian Eley

Escherichia coli 0157 is responsible for an emerging enteric disease which became a growing public health concern in 1996 with major outbreaks in Japan and Scotland…

Abstract

Escherichia coli 0157 is responsible for an emerging enteric disease which became a growing public health concern in 1996 with major outbreaks in Japan and Scotland. Unfortunately, the more common haemorrhagic colitis can at times develop into the haemolytic uraemic syndrome with associated renal disease which can lead to fatalities. It is now apparent that few bacterial cells are needed to spread infection and that cross‐contamination is therefore a significant problem. Although there are national programmes to investigate E. coli 0157 infection and gain new information on epidemiology, handwashing is seen as a very simple but effective approach to prevent transmission from contaminated material to food. We need to be made aware of the clinical importance of E. coli infection and how best we can bring it under control.

Details

Nutrition & Food Science, vol. 97 no. 3
Type: Research Article
ISSN: 0034-6659

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Article

G.F. Asensi, E.M.F. dos Reis, E.M. Del Aguila, D. dos P. Rodrigues, J.T. Silva and V.M.F. Paschoalin

This paper seeks to optimize a multiplex PCR in order to detect the incidence of Salmonella and Escherichia coli (E. coli) in chicken carcasses, eliminating a pre‐culture…

Abstract

Purpose

This paper seeks to optimize a multiplex PCR in order to detect the incidence of Salmonella and Escherichia coli (E. coli) in chicken carcasses, eliminating a pre‐culture enrichment step and the pathogen isolation.

Design/methodology/approach

A total of 30 chicken rinse carcasses were analysed by standard microbiological methods, and the isolates were identified by biochemical and serological tests. The results were compared with those obtained by a multiplex PCR using validated primers targeting for invA and lamB genes of Salmonella and E. coli, respectively.

Findings

Microbiological analysis showed the prevalence of Salmonella in 14 out of 30 chicken carcasses. The same rinse samples were also analysed by multiplex PCR, which allowed the simultaneous detection of both bacteria directly from the chicken rinse water microbial community.

Originality/value

The optimized mPCR detected enterobacteria directly from the rinse samples, a complex matrix food, in one workday. There was 100 per cent agreement of the conventional microbiological analysis with those results obtained by multiplex PCR.

Details

British Food Journal, vol. 111 no. 6
Type: Research Article
ISSN: 0007-070X

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Article

Enver Baris Bingol, Omer Cetin and Karlo Muratoglu

The purpose of this study is to investigate the effect of lemon juice on the survival of Salmonella Enteritidis and Escherichia coli in cig kofte (raw meatball).

Abstract

Purpose

The purpose of this study is to investigate the effect of lemon juice on the survival of Salmonella Enteritidis and Escherichia coli in cig kofte (raw meatball).

Design/methodology/approach

Cig kofte samples were inoculated one by one with both bacteria at high inoculum levels and were treated with different doses of fresh lemon juice (2, 5, 10 and 15 ml) for 10 seconds, 30 seconds, and 1, 5, 15, 30 and 60 minutes.

Findings

Treatments of lemon juice for different exposure times caused reduction ranging between 0.1 and 1.7 log CFU/g for Salmonella Enteritidis and 0.1 and 2.1 log CFU/g for E.coli. Results showed that lemon juice caused slight decrease in Salmonella Enteritidis and E.coli as an immediate inhibitor, but this effect increased with concentration and time.

Originality/value

This is a research study to provide information on the effectiveness of lemon juice which is squeezed generally before eating cig kofte, on the presence of the surface flora to strengthen the hygienic quality of the product. Inactivation effect of lemon juice on Salmonella Enteritidis and E.coli may give a practical and easy way of providing food safety for cig kofte.

Details

British Food Journal, vol. 113 no. 9
Type: Research Article
ISSN: 0007-070X

Keywords

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Abstract

Purpose

This paper aims to evaluate the microbial quality of some traditional cheese samples (sheep, cow and koopeh cheeses) consumed in northwest of Iran, and to detect Shiga-like-toxin-producing Escherichia coli (STEC) and methicillin-resistant Staphylococcus aureus (MRSA) in cheese samples by polymerase chain reaction (PCR) method.

Design/methodology/approach

Almost half of the project was based on counting the population of Staphylococcus aureus, total coliforms, Escherichia coli, and total aerobic mesophilic bacteria, also the other section was related to the isolation and the detection of the STEC and MRSA in cheese samples. The findings were compared with standard maximum and threshold values.

Findings

The results revealed that 36.99, 30.14 and 100% of cheeses exceeded the standard threshold value of E. coli (102), total coliforms (104) and S. aureus (102). However, total coliforms, in any of the cheese samples examined, did not reach the maximum value and only 24.66% of samples exceeded the maximum value of E. coli. Also, no significant difference (p > 0.05) in counts of each bacterial group examined in sheep, cow and koopeh cheeses was observed. The colony PCR method demonstrated the existence of 19 MRSA and 2 STEC isolates.

Originality/value

This research showed a general overview of the bacterial quality of cheeses in northwest of Iran.

Details

Nutrition & Food Science, vol. 49 no. 3
Type: Research Article
ISSN: 0034-6659

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Article

Keshia Naidoo and Denise Lindsay

The aim of this paper is to evaluate the hygiene of surfaces that come into direct contact with the ready to eat dried meat product, biltong, at point‐of‐sale in three…

Abstract

Purpose

The aim of this paper is to evaluate the hygiene of surfaces that come into direct contact with the ready to eat dried meat product, biltong, at point‐of‐sale in three different retailers in Johannesburg, South Africa, by investigating the presence of indicator organisms.

Design/methodology/approach

Samples were collected and plated in duplicate for aerobic plate, total Enterobacteriaceae, coliforms and Escherichia coli counts using standard methods. Typical E. coli colonies on Rapid E. coli 2 Agar™ were selected and further identified using 16S rDNA molecular sequencing methods.

Findings

Bacterial counts associated with biltong product ranged between 6–7 Log CFU/g, while counts on cutting utensils ranged between 5–6 Log CFU/cm2. Overall, the lowest counts were associated with display cabinets (2–6 Log CFU/cm2). Predominant populations were often similar between biltong product and various surface samples, indicating potential cross‐contamination. Results from 16S rDNA sequence analysis showed that E. coli strains isolated from biltong product and correspondingly from cutting utensils, were 100 per cent genetically similar. Strains of potential pathogens belonging to the Shigella dysenteriae group (99 per cent) were also identified.

Originality/value

This paper highlights that surfaces in direct contact with biltong, an increasingly popular dried meat commodity worldwide, may act as potential sources for cross‐contamination of product with potential food‐borne pathogens, which may hold foodborne illness implications.

Details

British Food Journal, vol. 112 no. 4
Type: Research Article
ISSN: 0007-070X

Keywords

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