The demands concerning microbial inhibitor tests were subjected to mar
ked changes during the last decades: It started with the claim of bein
g able to detect contaminated milk which might cause problems during f
ermentation processes ('technological safety'). Due to the present day
attention drawn to toxic and allergic hazards for numerous antimicrob
ials Maximum Residue Limits (MRLs) or safe/tolerance levels are fixed
('toxicological safety'). This means a variety of demands underlying p
ermanent changes with respect to the 'detection pattern' which cannot
be fulfilled by a single rest. Within an Integrated Dectection System
microbial inhibitor tests play an important role as screening methods
for those antimicrobials which can be detected with satisfactory sensi
tivities. This paper deals with some features of microbial inhibitor t
ests such as detection limits, performance, susceptibility for interfe
rence factors, qualitative determination and standardization.