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Evaluation of three decarboxylating agar media to detect histamine and tyramine‐producing bacteria in ripened sausages
Author(s) -
RoigSagués A.X.,
HernàndezHerrero M.M.,
LópezSabater E.I.,
RodríguezJerez J.J.,
MoraVentura M.T.
Publication year - 1997
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1046/j.1472-765x.1997.00223.x
Subject(s) - humanities , art
Histidine‐ and tyrosine‐decarboxylase activity of 175 strains of bacteria isolated from eight retail samples of Spanish ripened sausages was tested in three decarboxylating agars (Niven medium, Joosten and Northolt medium and modified decarboxylating agar of Maijala) and confirmed by an enzymic method (histamine) and thin‐layer chromatography (tyramine). Enterobacteria and pseudomonads showed the highest percentage of positive responses to histamine and tyramine in the three decarboxylating agars, but only enterobacteria were subsequently confirmed as histamine‐producing. Confirmed tyramine‐producing strains were all identified as enterococci or lactic acid bacteria. The medium described by Joosten and Northolt was more sensitive and faster at detecting tyramine‐producing micro‐organisms. However, all three media failed to detect one histamine‐positive strain of lactic acid bacteria used as a control.