Help for viable lactic acid bacteria staining using CTC

Estelle bacterio at
Mon May 31 04:33:04 EST 1999

I use 5-Cyano-2,3-ditolyl Tetrazolium Chloride (CTC) as indicator of
viability and activity of some lactic acid bacteria (Lactobacillus
plantarum, Lactococcus lactis, Pediococcus pentosaceus and Leuconostoc
mesenteroides). These strains are Gram positive, facultative anaerobic
and have fermentative metabolism. Tests have been realised with 12 h old

My problem is : CTC didn't stain L. plantarum and less than 40% of total
population of other strains was stained. Why ? (It's not  a problem of

If anybody using CTC could help me I would appreciate it. Can anyone
give me some methods to stain viable lactic acid bacteria ?

Thanks in advance,
Jean-Francois Meric

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