The oxytetracycline-glucose-yeast extract agar of Mossel, Visser & Mengerink (1962) for the selective enumeration of moulds and yeasts in foods has been extensively tested on 4000 samples of various materials in two food microbiology and one clinical laboratory. Its performance was excellent in that it suppressed entirely the growth of Bacillaceae. Only when examining stools from patients under tetracycline therapy did the medium insufficiently inhibit Enterobacteriaceae. Substitution of oxytetracycline by 60 pg/ml of gentamicin ww useful in such instances.

SUMMARYA survey was carried out on the occurrence of Vibrio parahaemolyticus on fish and shellfish, as sold in The Netherlands.The optimal mode of detection of this bacterium appeared to be: (i) enrichment of swabs taken from the surface and the gills in freshly prepared meat broth with 5 % NaCl; (ii) streaking onto Teepol bromothymol blue agar (BTB) and taurocholate bromothymol blue sucrose agar (TCBS); (iii) confirmation of suspect colonies by testing for mode of growth in butts/slants of a Kligler type glucose sucrose iron thiosulphate agar, formation of indole in 2 % NaCl 2 % trypticase water, anaerobic utilization of starch in the presence of 5 % NaCl and oxidase reaction according to Kovacs (1956).A total of 407 samples, stemming from 17 types of fish and shellfish, taken at three fish shops, was examined by this technique. Only one specimen, i.e. a haddock, was found to contain V. parahaemolyticus. This contamination rate of approximately 0-3 % correlates well with data found earlier for fish landed in Northern Germany.

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