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Biomedical subjects

D A Mossel

Publications and source records attributed to D A Mossel.

At least 73 records · Page 4Linked to original sources
PubMed1979

Occurrence of Vibrio parahaemolyticus in Dutch mussels.

A study was carried out on the occurrence of Vibrio parahaemolyticus in Dutch mussels originating from the East Schelde Estuary. In a totol of 79 10-g tissue samples, 3 (3.8%) were found to contain V. parahaemolyticus. In a second survey, 6 out of 23 bags of mussels (26%) contained one or more strains of V. parahaemolyticus in 5-g tissue samples. The many limitations of current methodology used in such surveys are stressed. Positive samples can be missed because viable cells may die during refrigerated transport. Surviving cells also may not be detected because they have been sublethally stressed. In addition, the unreliability of the identification criterion of no growth in 10% NaCl was demonstrated.

Animals↗
PubMed1977

[Involvement of veterinary medicine in, and its responsibility for, the microbiological safety of foods of animal origin (author's transl)].

Epidemiological data indicate that, in the majority of outbreaks, the aetiology of diseases of microbial origin transmitted by foods is the "dual failure": poor sanitary handling in addition to storage of perishable items at temperatures allowing of microbial proliferation. For statistical reasons, sampling and examination of final products is completely ineffective as a means to obtain safe foods and meals. Dependable assurance of microbiological safety of foods should rather be attained by the application of Good Manufacturing Practices. The shared responsibility for reliable, uninterrupted preventive safeguarding of the food chain calls for cooperation between line workers of various disciplines. Microbiological examination of final product samples is still meaningful in order to monitor Good Manufacturing Practices. Reference values ("standards" with which data obtained can be compared are essential for this purpose. Theri establishment, based on product sample surveys of factories previously examined for reliable operation of approved procedures, is outlined.

Bacterial Infections↗
PubMed1977

The reliability of the examination of foods, processed for safety, for enteric pathogens and Enterobacteriaceae: a mathematical and ecological study.

Because of the paucity of quantitative data on numbers of other enteric pathogens in food, the reliability of the examination of processed foods for Enterobacteriaceae was estimated taking Salmonella as a model. For this purpose an assessment was carried out of the risk of accepting Salmonella contaminated consignments of foods, despite a negative outcome of (i) examination of 1.5 kg samples for Salmonella; (ii) examination of one or two 1 g samples for Enterobacteriaceae; (iii) simultaneous application of both tests. The computations were based on the results of the examination of 6830 samples of dried foods, processed for safety, out of a total of 18170 samples.Only 69 samples permitted the exact calculation of the epsilon-factor, defined as c.f.u./g of Enterobacteriaceae/c.f.u./g of Salmonella; 4642 were positive for the former group but ;free' from Salmonella, and the rest were negative in both tests. Numbers of c.f.u./g for both groups, and hence the epsilon-factors, varied widely between commodities and also between different consignments of the same food product. The average for epsilon amounted to 5.8 x 10(3), far from the base-line value of 0.75 x 10(3) assessed earlier. In only 0.1% of samples did the Enterobacteriaceae test fail to achieve the required consumer protection.This investigation therefore substantiates that testing foods processed for safety by examining accurately chosen quantities for ecologically well selected and taxonomically thoroughly defined index organisms is a most effective procedure in terms both of consumer protection and simplicity of examination without compelling the food industry to achieve hardly attainable microbiological quality standards.

Bacteriological Techniques↗
PubMed1977

Development and use of single "polytropic" diagnostic tubes for the approximate taxonomic grouping of bacteria isolated from foods, water and medicinal preparations.

Single tubes, containing in all instances a bottom layer of a solid medium for detecting mode of attack on glucose, lactose, mannitol or starch and top layers of solid, semi-solid or liquid media allowing assessment of motility, formation of catalase, oxidase, coagulase, indole, hydrogen sulphide, acetyl methyl carbinol or pigments, as required ("polytropic" diagnostic tubes) were developed for the approximate taxonomic grouping of bacteria commonly encountered in foods, water and medicinal preparations. They are designated as: Gram negative diagnostic tubes (GNT), tubes allowing identification of E. coli, following the principle set out by MCKENZIE, TAYLOR and GILBERT (MTGT), diagnostic tubes for Vibrio parahaemolyticus (VPT), open tubes to assess oxidative attack on glucose (OGT), Gram positive diagnostic tubes (GPT), and mannitol plasma tubes (MPT) for the identification of Staph. aureus. In addition a CP tube for the identification of Cl. perfringens is described, the basis of which is the production of H2S from sulphite in the presence of cycloserine, absence of mitality and failure to produce indole at 46 degrees C. All tubes contain intermediate layers to avoid interactions between changes occurring in top and bottom layers. Upon examination of about 600 pure cultures from collections or freshly isolated from foods etc. such tubes have given results which were in agreement with those of classical testing; in a few instances (testing for indole formation) even better results were obtained. The use of such polytropic tubes in identification routes saving much time and effort is outlines.

Bacteria↗
PubMed1977

A simplified procedure for the examination of drinking water for bacteria of public health significance: the differential hydrobacteriogramme.

A new method is described which can be used for the examination of piped drinking water. It is also suitable for monitoring water which was initially of potable quality, and is intended for reuse in the food industry. The method is based on CLARK's "P-A test" and, because this allows many bacterial types to be detected, i.e. Enterobacteriaceae, E. coli, P. aeruginosa, Aeromonadaceae and LANCEFIELD group D streptococci it is called differential hydrobacteriogramme. A preliminary resuscitation treatment to revive sublethally injured cells is essential in this procedure. In earlier work this was attained by adding an equal volume of double strength nutrient broth and later double strength MACCONKEY purple broth, making the method somewhat bulky. In the new procedure, after the resuscitation step, a concentrated bile salts/indicator solution is added, allowing subsequent selective enrichment of the taxa sought. Positive enrichment cultures are examined for these organisms by the procedures summarized in Fig. 1. The new method, when tested on approx. 150 artificially inoculated and 92 natural samples, showed the same productivity and selectivity as the one introduced earlier. The new method is recommended for routine monitoring purposes, because it is less bulky.

Aeromonas↗