Proteolytic microorganisms in curd dairy products with reference to histidine decarboxylase activity on niven modified medium

Abstract EN

In this work.

180 samples of cheese (Ras, Damietta, and kareish) and plain yoghurt, 45 from each were collected from dairy shops, superm-arkets and markets at different localities of Alexandria city.

The colle-cted samples were examined bacteriologically.The obtained results revealed that total Coliform count (MPN / g) in Ras, Damietta, Kareish cheese and plain yoghurt were 1.6 × 103, 1.45 × 103, 1.28 × 103 and 1.30 × 103, respectively while Entercococcus counts (MPN / g) were 4.77 × 105, 9.07, 8.54 × 106 and 7.40 × 105 respectively and Bacillus cereus counts (cfu / g) were 2.12 106, 6.29 × 104, 1.21 × 106 and 5.10 × 104, respectively.

and examination for incidence of bacterial species (E.

coli, K.

pneumoniae, K.

ozaenae, K.

oxytoca, K.

rhinoscleromatis, Cit.

diversus, Cit.

freundii, Ent.

cloacae, Ent.

aerogenes, Enterococcus faecalis, Enterococcus faecium, Enterococcus durans, Ps.

aeruginosa, Ps.

fluorescens, and B.

cereus) for production of histidine decarboxyl-ase enzyme on Niven modified medium incubated at 37°C for 24 to 72 hr.

The most of microorganisms can produce histidine decarboxylase enzyme at varying percentages.

The public health significance of the isolated histamine producing organisms were discussed.