Microbiological examination of ready-to-eat stuffing from retail premises in the north-east of England. The 'Get Stuffed' survey.

AIMS: To establish the microbiological quality of ready-to-eat stuffing from retail premises in the north-east of England. To establish threshold levels of bacteria in the product for acceptance as a ready-to-eat food. To determine the relationship between the microbiology of the product and production processes. METHODS AND RESULTS: A microbiological study of ready-to-eat stuffing using validated methods was performed on 147 samples from 139 retail premises. The determinants investigated were as follows: aerobic colony count, Escherichia coli, Enterobacteriaceae, Staphylococcus aureus, Bacillus spp., Salmonella spp. and Campylobacter spp. Results indicate that using current guidelines 76.3% were satisfactory, 15.6% were acceptable and 8.2% were of unsatisfactory quality. CONCLUSIONS: Unsatisfactory results were due to high aerobic colony counts, E. coli, Enterobacteriaceae and S. aureus. There were significant associations between bacteriological quality and temperature of storage, food hygiene training, product discard policy and confidence in management scores. SIGNIFICANCE AND IMPACT OF THE STUDY: The microbiology of ready-to-eat stuffing suggests that this is a relatively safe product. It is suggested that the product be placed in food category 3 in the current guidelines for ready-to-eat foods.

The use of Lenticules for the process control of enumeration techniques in food and environmental microbiology.

AIMS: Lenticules consist of control-dried plano convex discs in which biologically-active materials are contained within a water-soluble matrix. They can be produced to contain stable numbers of bacteria from 10 cfu lenticule-1 to 108 cfu lenticule-1 with a wide variety of organisms. These experiments were carried out to validate their use as a tool for internal quality control in quantitative microbiology. METHODS AND RESULTS: The Lenticules were used routinely in standard quantitative microbiological procedures across five laboratories. Results showed the materials to be stable, homogeneous and capable of identifying systematic errors. CONCLUSIONS: The Lenticules provide suitable, stable control materials. SIGNIFICANCE AND IMPACT OF THE STUDY: Routine internal quality control of quantitative measurements is greatly improved; the materials are easy to use and enable comparisons between laboratories to be made.

Pulsed field gel electrophoresis identifies an outbreak of Salmonella enterica serotype Montevideo infection associated with a supermarket hot food outlet.

In February 1996 Salmonella enterica serotype Montevideo infection in a patient in the North Tyneside area was attributed to consumption of cooked chicken bought from a supermarket hot food outlet. Isolates from the patient, leftover food, and environmental samples were indistinguishable by pulsed field gel electrophoresis (PFGE). PFGE also demonstrated that an outbreak of infection with S. Montevideo associated with the hot food outlet had occurred in late 1995 and early 1996. This study shows the importance of microbial strain discrimination in outbreak investigations and illustrates the value of close liaison between microbiologists, epidemiologists, and environmental health officers in the control of salmonella outbreaks.

Lenticules for the control of quantitative methods in food microbiology.

Control dried organisms as lenticules are a dependable and convenient alternative to wet cultures for quality assurance and process controls in routine food microbiology. Lenticules are designed to give a fixed, reproducible inoculum over an extended period of time without loss of cultural characteristics or viability. During a period of 23 months, 596 paired counts were performed by both Miles and Misra and spiral plating techniques on lenticule controls. Correlation between the two methods and within batches was excellent. Only 14 counts (2.5%) fell outside the standard operating limit of 0.5 log10. All were within 1.0 log10. On two separate occasions, replicate runs were performed on five reconstituted lenticules from a batch. The counts obtained showed variation within and between lenticules only slightly in excess of what is expected by chance. Lenticule replicates performed by three other laboratories also produced satisfactory results. It is thought that lenticules could improve the accuracy of total plate counts and lead to a better standardization of quantitative methods in food microbiology within and between laboratories.

Legionella pneumophila species identification using a commercial latex agglutination kit: a potential cross-reaction problem with serogroup 12.

Seventy-nine strains of legionella spp. and 13 non-legionella isolates were tested using a commercial latex agglutination kit. Cross-reactions were observed for all strains of Legionella pneumophila serogroup 12 examined between latex particles coated with rabbit antibodies raised against L. pneumophila serogroup 1 and those coated with rabbit antibodies to serogroups 2-14. Strains of L. pneumophila serogroup 1 did not cross-react with latex particles directed against L. pneumophila serogroups 2-14. This suggests that L. pneumophila serogroup 12 shares common surface antigens with L. pneumophila serogroup 1, and that conversely serogroup 1 isolates do not share major surface antigen determinants with serogroups 2-14. All other isolates tested gave expected results.

Incrimination of an environmental source of a case of Legionnaires' disease by pyrolysis mass spectrometry.

Following a case of Legionnaires' disease Legionella pneumophila of the same serogroup was isolated from the hot water system of the hotel which had been epidemiologically implicated as the source of the infection. Pyrolysis mass spectrometry (PyMS) was used to compare 11 isolates from the hotel water sample with the patient's strain. Epidemiologically unrelated isolates, both clinical and environmental, of the same serogroup and monoclonal antibody type of L. pneumophila were included in the same analysis, together with relevant reference strains. The patient strain was shown to be indistinguishable from seven of the hotel water isolates, but clearly different from other unrelated clinical isolates, the reference strains and some of the other environmental isolates. PyMS is a rapid and cheap method for inter-strain comparison for L. pneumophila.

The incidence of Bdellovibrio spp. in man-made water systems: coexistence with legionellas.

Bdellovibrios have been isolated from surface waters but there are no reports of its occurrence in mains water supplies. One hundred and thirty five water samples from 81 sources were examined for the presence of Bdellovibrio bacteriovorus and Legionella spp. Bdellovibrios were isolated by a double-layer agar technique with two strains of Legionella pneumophila serogroup 1 as the host organisms. Bdellovibrio spp. were isolated from 57.8% and Legionella spp. from 9.5% of the samples. The two species occurred together in 4.4% of samples. The incidence of Bdellovibrio spp. and its occurrence with legionellas in man-made water systems is discussed.

Effectiveness of geriatric rehabilitative care after fractures of the proximal femur in elderly women: a randomised clinical trial.

OBJECTIVE: To compare postoperative collaborative care between orthopaedic surgeons and physicians in geriatric medicine with routine orthopaedic care in elderly women with proximal femoral fracture. DESIGN: Exclusion of patients dying before fit enough to enter trial, those with pathological fractures, those likely to be discharged within seven days of entering the trial, and those remaining unfit for transfer to a peripheral hospital. Remainder allocated to two groups: treatment group and control group. SETTING: District hospital acute admission ward and rehabilitation ward. PATIENTS: 144 sequentially admitted elderly women with proximal fracture of the femur; 36 excluded on above criteria and remainder entered into trial. INTERVENTION: Both treatment and control groups (n = 54 in each) received physiotherapy and other services. The treatment group also received thrice weekly supervision by a geriatrician. END POINTS: Physical independence, residence after discharge, and length of hospital stay. MEASUREMENTS AND MAIN RESULTS: At discharge significantly more patients in treatment group were independent in terms of activities of daily living than controls (41 v 25) and their median stay was 24 days (range 8-197) compared with 41 (9-365) (95% confidence intervals for difference 2 to 25). Significantly fewer treatment patients were discharged to institutional care (10% v 32%; 95% confidence interval for difference 6% to 37%) and more to their own homes (63% v 38%; 95% confidence interval for difference 6% to 44%). These beneficial effects were consistent across a range of ages and mental state. CONCLUSIONS: Both hospital and patient benefited when postoperative rehabilitation was provided in a setting specialising in such care for elderly patients with trauma.