Quantitative risk assessment of human listeriosis from consumption of soft cheese made from raw milk

Microbial hazards have been identified in soft cheese made from raw milk. Quantification of the resulting risk for public health was attempted within the frame of the Codex Alimentarius Commission, 1995 approach to quantitative risk assessment, using Monte Carlo simulation software. Quantitative data could only be found for Listeria monocytogenes. The complete process of cheese making was modeled, from milking to consumption. Using data published on the different sources of milk contamination (environment and mastitis) and bacterial growth, distributions were assumed for parameters of the model. Equations of Farber, J.M., Ross, W.H., Harwing, J. (1996) for general and at-risk populations were used to link the ingested dose of L. monocytogenes to the occurrence of listeriosis. The probability of milk contamination was estimated to be 67% with concentration ranging from 0 to 33 CFU ml⁻¹. The percentage of cheese with a predicted concentration of L. monocytogenes greater than 100 CFU g⁻¹ was low (1.4%). The probability of consuming a contaminated cheese serving was 65.3%. Individual annual cumulative risk of listeriosis, in a population each consuming 50 servings of 31 g, ranged from 1.97 × 10⁻⁹ to 6.4 × 10⁻⁸ in a low-risk sub-population and 1.04 10⁻⁶ to 7.19 10⁻⁵ in a high-risk sub-population. The average number of expected cases of listeriosis per year was 57 for a high-risk sub-population and one for a low-risk healthy sub-population. When the frequency of environmental milk contamination was reduced in the model and L. monocytogenes mastitis was eliminated, the expected incidence of listeriosis decreased substantially; the average number of expected cases was reduced by a factor of 5. Thus the usefulness of simulation to demonstrate the efficiency of various management options could be demonstrated, even if results should be interpreted with care (as many assumptions had to be made on data and their distributions).     

Influence of diet on the intestinal microflora and meat flavour of intensively‐reared broiler chickens

1. An attempt has been made to modify the composition of the gut flora of broiler chickens by dietary means in order to determine any concurrent changes in meat flavour.

2. Birds given a diet containing an increasing proportion of whole wheat supplemented with fresh green vegetable matter (special diet) were compared with conventionally‐fed controls. At 12 weeks of age those receiving the special diet had 10 to 100‐fold higher counts of Escherichia colt and faecal streptococci in the duodenum and lower small intestine and showed differences in the intestinal incidence of species and biotypes of lactobacilli.

3. Evaluation of cooked breast‐meat samples by a trained sensory panel showed a significant difference in flavour (P < 0.01) between conventional and special‐diet birds which varied from perceptually very slight to slight. The main terms used in distinguishing special‐diet birds from conventional controls included ‘richer’, ‘meatier’ and ‘sweeter’.

4. Storage of plucked, uneviscerated birds at 4 °C for 8 d maintained the flavour difference between the dietary groups but the effect of storage on flavour was greater in both groups of birds than the influence of diet alone. The likely influence on flavour of autolytic changes occurring in the muscle during storage of the birds is discussed.     

The representation and functional composition of carabid and staphylinid beetles in different field boundary types at a farm-scale

At the farm-scale, hedgerow, degraded hedgerow and fence field boundary types were sampled for overwintering carabid and staphylinid beetles. Distinct beetle assemblages were evident and the structural and botanical characteristics of the boundary types were good explanatory factors of the differences. Each field boundary type supported unique species not found elsewhere; nine species were contributed by hedgerows alone and six species each from degraded hedgerows and fences. Using a systematic complementary site selection method we determined that all field boundary types were of equal importance for full representation of carabid and staphylinid species at the farm-scale. Additionally, fence habitats supported generalist predators of crop pests in greatest densities, whilst degraded hedgerows were most valuable in providing refuge to species vulnerable to disturbance and habitat fragmentation. Contrary to expectation, woodland species were not more evident in hedgerows than either degraded boundaries or fence habitat. This study provides empirical evidence that some components of biodiversity and sustainable farming are best maintained by retaining habitat heterogeneity, including features currently considered of limited conservation value.     

Antigenic and morphological differentiation of placental and intestinal isolates of Chlamydia psittaci of ovine origin.

Ewe placental and lamb intestinal isolates of Chlamydia psittaci recovered from flocks affected with ovine enzootic abortion were examined by inclusion morphology, indirect immunofluorescence (IIF) and immunoblot analysis. Chlamydiae recovered from the faeces of sheep from two flocks free of clinical disease were also examined. In cell culture ovine abortion (OA) and intestinal isolates were distinguishable by inclusion development and morphology. Similarly, in two-way IIF tests with one week mouse antisera isolates fell into two distinct groups: abortion or intestinal. Immunoblotting with convalescent sheep abortion antiserum identified 30 out of at least 40 silver staining polypeptides as antigenic both in OA and intestinal isolates. The serum produced a similar reaction pattern to the resolved proteins of each OA isolate, indicating a higher degree of antigenic conservation among these isolates. Considerable cross reactivity between the OA and intestinal isolates was identified, but the serum also showed apparent molecular weight differences between antigens of the two types in the 87-116 kDa, 38-44 kDa and 26-28 kDa regions. Furthermore, the immunoblotting analysis revealed heterogeneity among the intestinal isolates, particularly in antigens between 87-116 kDa and 38-44 kDa.     

ULTRASONOGRAPHY VERSUS RADIOGRAPHY FOR DETECTION OF FLUID IN THE CANINE TYMPANIC BULLA

The tympanic bullae of 20 previously healthy cadaver animals were randomly filled with sterile saline or air. The heads were positioned using tape ties and a rostrocaudal open mouth radiograph taken. The resulting radiographs were assessed by a blinded ECVDI diplomate, with each tympanic bulla being recorded as being either air or fluid filled. Ultrasound examination of the bullae was performed, by a blinded assessor, using a B-mode 5 mHz sector probe (Sonotron-VingMed Sound A/S, PO Box 141, N3191, Horten, Norway) operating at 3 mHz. Each bulla was recorded as being either air or fluid filled. Results of radiography and ultrasonography were each compared to the actual status of the bulla in a chi square analysis. Sensitivity of radiography was 80%, with specificity of 65%. Ultrasonographic sensitivity was 100% and specificity 100%. Ultrasonography may in future provide a cheap, noninvasive, rapid and widely available method for diagnosing otitis media in clinical cases.     

Transcatheter intravascular stent placement to relieve supravalvular pulmonic stenosis

Valvular pulmonic stenosis has been successfully treated in dogs via minimally invasive transcatheter balloon dilation procedures for almost 20 years. Supravalvular pulmonic stenosis however is not amenable to balloon dilation procedures. Although several surgical procedures are described for treatment of pulmonic stenosis, the morbidity and mortality of these procedures are significantly higher than for transcatheter approaches.Two cases of supravalvular pulmonic stenosis are presented, one acquired and one congenital, which were successfully treated with transcatheter intravascular stent placement. The procedure alleviated the stenotic lesion and resolved clinical signs.     

A comparison of cerebral arteriography and cavernous sinus venography in the dog

The technique and relative merits of cerebral arteriography and cavernous sinus venography are reviewed. Of seven cases investigated by cerebral arteriography, only one case showed evidence of abnormality and this was confirmed at post-mortem. Of nine cases investigated by cavernous sinus venography, six cases had positive findings, five of which have subsequently been substantiated pathologically.
Résumé. On passe en revue les techniques et les mérites relatifs de l'artériographie cérébrale et de la veinographie du sinus cavnereux. Sur 7 cas soumis à l'artériographie cérébrale, un seul a presénté des anomalies confirmées à l'autopsie. Sur les 9 cas dans lesquels on a utilisé la veinographie du sinus caverneux, 6 ont donné des résultats positifs et parmi eux, 5 ont reçu une confirmation anatomo-pathologique ultérieure.
Zusammenfassung. Die Methoden und relativen Vorzüge der cerebralen Artériographie und der cavernösen Sinusvenographie werden besprochen. Von den sieben mit cerebraler Artériographie untersuchten Fällen zeigte nur einer Anzeichen von Anomalität, die bei der Autopsie bestätigt wurde. Von neun Fällen, die mit cavernösen Sinusvenographie untersucht wurden, ergaben sechs positive Befunde, von denen fünf später pathologisch bestätigt wurden.     

Neuromuscular disease in dogs: some aspects of its investigation and diagnosis

The techniques used in clinical investigation of muscle disease are discussed with particular reference to the use of EMG and muscle biopsy. Cryostat sections of muscle are used for rapid diagnosis but their main function is for the performance of investigative enzyme histochemistry. A brief review of the commoner diseases of muscle is presented, the material being obtained principally from the Veterinary Surgery Department at Glasgow. These diseases include neurogenic disorders, muscular dystrophy and various inflammatory diseases. It is suggested that a large number of myopathies occur in dogs which will be revealed by further studies. Examples of these are myopathies in association with malignancies. It is emphasized that for an accurate and complete investigation clinical, biochemical, electrical and pathological studies must be performed on the cases presented. Résumé. Les techniques employées dans l'investigation clinique des maladies musculaires sont traitées particulièrement en référence avec L'utilisation de l'électromyogramme et de la biopsie musculaire. Les coupes microscopiques cryostatiques du muscle permettent d'établir un rapide diagnostique, mais leur fonction principale réside dans la recherche histochimique sur les enzymes. Les maladies musculaires les plus communes sont rapidement passées en revue, les matériaux provenant en majeure partie du Département de Chirurgie Vétérinaire de Glasgow. Ces maladies comprennent les troubles neurogènes, l'atrophie musculaire et diverses troubles inflammatoires. Il est suggéré que, chez les chiens, se trouve un grand nombre de myopathies qui pourront ětre révélées par des études plus approfondies. Pour que l'investigation soit exacte et complète, il est absolument indispensable de procéder à la fois aux études biologique clinique, électrique et pathologique dans chacun des cas présentés. Zusammenfassung. Die Techniken, die man in klinischer Erforschung von Muskelerkrankung anwendet, sind diskustert mit besonderem Hinweis auf den Gebrauch von EMG und Muskelbiop-sie. Kryostat Sektionen von Muskeln werden fur schnelle Diagnosen gebraucht, aber ihre Haupt-funktion ist fur die Ausfuhrung von erforschender Enzym-Histochemie. Ein kurzer Uberlick von allgemeinen Muskelkrankheiten wird dargelegt, das Material erhielt man hauptsǎchlich von der Veterinaren Chirurgie Abteilung in Glasgow. Dièse Krankheiten schliessen nervursprùngliche Stǒrungen, Muskelschwund und verschiedene Entziindungskrankheiten ein. Es wird angedeutet, dass eine gross Anzahl von Muskelleiden in Hunden vorkommt, welche sich durch weitere Studien zeigen werden. Beispiele von diesen sind Muskelleiden in Verbindung mit Malignitàten. Man mǒchte besonders betonen, dass fiir eine genaue und komplette Erforschung klinisch biochemische, elektrische und pathologische Studien von Fall zu Fall ausgefiihrt werden mǔssen.     

A radiochemical and gas-chromatographic study of the determination of dichlorvos residues in stored grain

An investigation into the extraction of dichlorvos from stored grain and satisfactory storage conditions for samples received for analysis has been carried out using [³²P]-dichlorvos. It has been shown that samples can be effectively stored at —17° C and that methanol can be used for the extractable dichlorvos but does not remove the organophosphorus residue bound to the grain.