No abstract

The objectives of this study were to examine domestic food safety knowledge levels of consumers, establish the levels and incidence of bacterial contamination and operational temperatures in domestic refrigerators, and identify areas in which consumer food safety education is necessary in Ireland. A food safety knowledge questionnaire applied to a representative sample of households (n = 1,020) throughout the island of Ireland found the gaps in consumer food safety knowledge. Analysis of swab samples (n = 900) recovered from the domestic refrigerators in these households showed average total viable counts of 7.1 log CFU/cm2 and average total coliform counts of 4.0 log CFU/cm2. Analysis of swab samples also detected the incidence of Staphylococcus aureus (41%), Escherichia coli (6%), Salmonella enterica (7%), Listeria monocytogenes (6%), and Yersinia enterocolitica (2%). Campylobacter jejuni and E. coli O157:H7 were not detected in domestic refrigerators. The temperature profiles of a subset of the sampled refrigerators (100) were monitored for 72 h, and 59% were found to operate, on average, at temperatures above the recommended 5 degrees C. Knowledge and temperature survey results varied considerably, but consumers who scored better in terms of basic food safety knowledge had reduced levels of bacterial contamination in their refrigerators and reported a reduced incidence of food-associated illnesses. This study confirms the effect of basic food hygiene knowledge on hygienic practice and identifies specific areasfor emphasis in the development and delivery of effective food safety risk communication messages to consumers.

This study investigated the possibility that sublethal food preservation stresses (high or low temperature and osmotic and pH stress) can lead to changes in the nature and scale of antibiotic resistance (ABR) expressed by three food-related pathogens (Escherichia coli, Salmonella enterica serovar Typhimurium, and Staphylococcus aureus). The study found that some sublethal stresses significantly altered antibiotic resistance. Incubation at sublethal high temperature (45°C) decreased ABR. Incubation under increased salt (>4.5%) or reduced pH (<5.0) conditions increased ABR. Some of the pathogens continued to express higher levels of ABR after removal of stress, suggesting that in some cases the applied sublethal stress had induced stable increases in ABR. These results indicate that increased use of bacteriostatic (sublethal), rather than bactericidal (lethal), food preservation systems may be contributing to the development and dissemination of ABR among important food-borne pathogens.

Aims: In the past eight to 10 years, reports of antibiotic resistance in food‐borne isolates in many countries have increased, and this work examined the susceptibility of 1001 food isolates of Listeria species. Methods and Results: Susceptibility/resistance to eight antibiotics was determined using the Bauer–Kirby disc diffusion assay, and 10·9% of the isolates examined displayed resistance to one or more antibiotics. Resistance to one or more antibiotics was exhibited in 0·6% of Listeria monocytogenes isolates compared with 19·5% of Listeria innocua isolates. Resistance was not observed in Listeria seeligeri or Listeria welshimeri. Resistance to tetracycline (6·7%) and penicillin (3·7%) was the most frequently observed, and while resistance to one antibiotic was most common (9·1%), isolates resistant to two or more antibiotics (1·8%) were also observed. Conclusions: While resistance to the antibiotics most commonly used to treat human listeriosis was not observed in L. monocytogenes, the presence of such resistance in other Listeria species raises the possibility of future acquisition of resistance by L. monocytogenes. Significance and Impact of the Study: The higher level of resistance in L. innocua compared with L. monocytogenes suggests that a species‐related ability to acquire resistance to antibiotics exists.

The‐survival‐characteristics‐of‐a‐non‐toxigenic,‐antibiotic‐resistant‐strain‐of‐Escherichia‐coli‐O157:H7‐in‐bovine‐faeces‐were‐investigated.‐Faecal‐samples‐were‐inoculated‐with 108‐9‐cfu‐g−1‐of‐the‐organism‐and‐(i)‐stored‐in‐closed‐plastic‐containers‐at‐10 °C, (ii) stored in closed plastic containers placed outside or (iii) decanted onto the surface of grazing land. Recovery and enumeration on Sorbitol MacConkey Agar (SMAC) and Tryptic Soya Agar (TSA) revealed that the E. coli O157:H7 numbers in both enclosed samples (i and ii) had decreased by 4·5–5·5 log10 cfu g−1 within 99 d. Numbers in samples decanted onto grassland (iii) decreased by 4·0–5·0 log10 cfu g−1 within 50 d but the organism was still detectable in the surrounding soil for up to 99 d. Persistence of E. coli O157:H7 in bovine faeces and contaminated pastures may therefore be an important factor in the initial infection and re‐infection of cattle.