R.H. Madden

Frequency of occurrence of Campylobacter spp. in red meats and poultry in Northern Ireland and their subsequent subtyping using polymerase chain reaction‐restriction fragment length polymorphism and the random amplified polymorphic DNA method

Sampling of lamb (n = 100) and beef (n = 100) carcasses in abattoirs in Northern Ireland produced no evidence of Campylobacter spp. contamination and when retail packs of beef (n = 50) and pork (n = 50) were sampled these were also apparently free of Campylobacter spp. However, 38% of retail packs of chicken pieces (n = 120), yielded Campylobacter spp. These packs were purchased over a period of 1 year and came from a single local producer. After the species of the isolates had been determined (Campylobacter jejuni and Camp. coli were found in approximately equal numbers) they were subtyped using both polymerase chain reaction‐restriction fragment length polymorphism (PCR‐RFLP) and the random amplified polymorphic DNA (RAPD) method of typing. All of the poultry isolates were successfully typed by these methods, in contrast to the results obtained with serotyping where several isolates were found to be untypable. PCR‐RFLP typing showed that specific subtypes were isolated repeatedly over a period of 1 year in the output of the producer studied. The more discriminating RAPD confirmed this observation, but with fewer isolates. This appears to indicate recurrent infection of broilers whose source can now be investigated using the methodologies developed.

INTER-LABORATORY EVALUATION OF THREE FLAGELLIN PCR/RFLP METHODS FOR TYPING CAMPYLOBACTER JEJUNI AND C. COLI: THE CAMPYNET EXPERIENCE

Aims: To compare typeability, discriminatory ability, and inter‐laboratory reproducibility of three flagellin PCR/RFLP (fla typing) methods previously described for Campylobacter.

Presence of Listeria and Salmonella spp. in retail chicken in Northern Ireland

Aims: Retail packs of fresh chicken in Northern Ireland were sampled to determine the frequency with which they were contaminated with Salmonella and Listeria spp.

Comparison of 40 Salmonella enterica serovars injured by thermal, high-pressure and irradiation stress

Aim:  To investigate and compare the inherent resistance of 40 Salmonella serovars to heat, irradiation and high‐pressure stress.

Optimising recovery of Campylobacter spp. from the lower porcine gastrointestinal tract

To determine the incidence of campylobacters in Northern Ireland pigs, ileal contents and anal swabs were taken shortly after death. Direct streaking onto Preston agar, and modified charcoal cefoperazone desoxycholate agar (mCCDA), were compared, as was enrichment in selective broths prior to streaking onto the corresponding solid medium. For anal swabs direct plating on mCCDA was most efficient, with 100% of samples positive, whilst for ileal contents enrichment in mCCD broth was best with 86% of samples positive. Although only 34% of ileal samples enriched in Preston broths were positive they yielded three species not isolated from mCCD broth, and hence indicated that some pigs were infected by at least two species of Campylobacter. Overall, the number of samples found to contain campylobacters, and the range of species isolated, was seen to be markedly affected by both the choice of selective medium and the isolation procedures.

The effect of thermal stress on Campylobacter coli

Aim: Enteropathogenic Campylobacter jejuni, Camp. coli and Camp. lari are currently the most common cause of acute infectious diarrhoeal illness in the UK. Many domestic animals, including pigs, act as natural reservoirs for these organisms and infection may occur through the ingestion of contaminated foodstuffs. The safety of locally produced porcine liver was assessed in relation to the heat susceptibility of Campylobacter spp. present in eviscerated product.

Carriage of four bacterial pathogens by beef cattle in Northern Ireland at time of slaughter

Aims:  To determine the prevalence of four bacterial zoonotic pathogens in beef cattle at time of slaughter in Northern Ireland (NI), in order to assess their potential for reducing beef safety.

A genotyping investigation of the colonization of piglets by Campylobacter coli in the first 10 weeks of life

Aims:  To examine the Campylobacter genotypes colonizing a litter of piglets during the first 10 weeks of life and compare them with those of the sow.

Diversity of Campylobacter coli genotypes in the lower porcine gastrointestinal tract at time of slaughter

Aims:  To compare the genotypes of Campylobacter coli obtained from the rectal and ileal samples of pigs at the time of slaughter.

Use of Hugh and Leifson’s medium as a simple screening test to aid in the differentiation of Arcobacter spp. from background flora during their isolation from foodstuffs

Aims:  To investigate the suitability of Hugh and Leifson’s medium (HLM) as the basis of a simple screening test to differentiate between contaminants and Arcobacter spp. during their isolation from foodstuffs.