Does sodium azide sold as azidiol tablets affect the initial standard plate count (colony count) from milking until the milk sample is analyzed. Reports have suggested that azidiol reduces the standard plate count and thus should not be used as a preservative. I would appreciate any clarification regarding this issue.
Hi,
Sodium azide is inhibitor factor against more bacterial species as Lactobacilli and it used milk preservative in some African countries but some bacteria as Streptococci can grow in 1% Sodium azide.
Hi,
Sodium azide is inhibitor factor against more bacterial species as Lactobacilli and it used milk preservative in some African countries but some bacteria as Streptococci can grow in 1% Sodium azide.
Hello George... Azidiol is a preservative (biocide). This preservative contains a mixture of sodium azide, chloramphenicol, bromophenol blue and sodium citrate.
Sodium azide is a useful probe reagent, mutagen, and preservative. Commonly used as a preservative for laboratory and hospital reagents as a bacteriostatic agent in storage solutions.The typical effective concentration usually ranges from 0.02% to 0.1% (w/v). Sodium Azide is an inhibitor of peroxidase, SOD, catalase, haemoprotein enzymes and O2 evolution in photosynthesis. The mechanism of its inhibition and toxicity may be due to metal ion complexation and displacement from enzyme.
Obviously Sodium azide Inhibits gram negative flora and reduces the standard plate count in milk.
Use of Azidiol in milk-testing laboratories has become compulsory in some country (Eg. Spain), and in some African country as suggested by Alaa Kareem Niamah. Sodium azide is not commonly used as a milk preservative in North America. because the possibility of spontaneous explosions caused by sodium azide reacting with metals in waste system pipes within laboratory buildings and in sewage systems.
One research article by M Borràs and others (2013) is attached, the study was to evaluate the effect of storage time (4 °C) on milk samples and the use of
azidiol as preservative on the results of microbial inhibitor tests used to detect antimicrobials in milk. You can refer it for the details.
Thank you Dr. Laxmana Naik and Dr.Alaa Kareem Niamah for the information you have presented, from my previous reading (http://eeb.lu.lv/EEB/2007/Seskena.pdf) I understood that azidiol is a bacteriostatic agent (which stops the existing microbial population from growing) and this is the reason why it is used as a preservative in milk samples as it stabilzes the microbial population after milking until testing, this theoretically will give you a standard plate count which is representative of the milks condition once it was milked from the animal.
I understand that sodium azide (is a biocide) and does infact reduce the standard microbial count in milk samples due some bacterial species being sensitive such as gram negative flora and lactobacilli, if this is the case then why is azidiol (which contains sodium azide) used widely as a preservative in milk samples for the standard plate count when in fact this leads to misleading results and counts are lower than expected and the milk's condition is not represented by the azidiol containing milk sample?? Does azidiol only lead to a certain percent reduction in microbial population in a milk sample, if yes what percent and do you have any references?
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