STABILITY STUDY AND EXPIRY DATE DETERMINATION OF TRYPTIC SOY AGAR (TSA) MEDIUM PRODUCED AT THE NATIONAL INSTITUTE FOR CONTROL OF VACCINES AND BIOLOGICALS

Abstract

Currently, laboratories at the National Institute for Control of Vaccines and Biologicals that meet GLP and ISO 17025:2017 standards are controlled for temperature, humidity, air speed rate and microbiological monitoring. Tryptic Soy Agar (TSA) is being used in microbiological testing processes with methods such as: settle plates, volumetric air and surface sampleing for microbial colony cultures. To study the stability and determine the shelf life of the TSA medium, the research team from the Department of Experimental Media produced 03 lots of TSA medium at the end of July 2024, then stored them at temperature from 2 to 8°C for period of 4 months (August – November 2024) and evaluated the quality of the criteria: sensory characteristics, pH, sterility and microbial growth at different times (0 week, 2 weeks, 4 weeks, 6 weeks, 8 weeks, 10 weeks, 12 weeks, 13 weeks, and 14 weeks). The results indicated that the TSA media lots still met the quality standards after 12 weeks of storage. For the microbial growth criteria, at week 13 and 14, the recovery value of microbial strains on the lots decreased lower than the standard value (≥70%). Therefore, the research team recommends that the shelf life of the TSA media is 3 months from the date of manufacture.