Question

How do I store non-sterile culture media in dissolved form in the fridge in a clean but non-sterile container? The powder of the media (Broth, Nutrient agar, MAC, or MH agar) will be put in a glass bottle filled with distilled water and then dissolved/mixed in the microwave. Would a 12-hour to 16-hour storage in the fridge prior to sterilization, thereafter, affect the media performance?

Answer 1

Storing non-sterile culture media such as Broth, Nutrient agar, MAC, and MH agar in a refrigerator for a short time before sterilization is possible, provided the risk of contamination is minimized, and the media's integrity is maintained. However, for best practice and optimal results, sterilization should be done as soon as possible after preparation.

Step-by-step explanation:

When storing non-sterile culture media in a fridge, the quality of the media for bacterial growth can be affected. Culture media such as Broth, Nutrient agar, MacConkey Agar (MAC), and Mueller-Hinton agar (MH agar) must be sterilized to ensure the removal of unwanted microbes. Though the media is non-sterile at the time of preparation, placing it in the fridge for 12 to 16 hours prior to sterilization can be acceptable if contamination is minimized. The main concern would be the potential for microbial contamination given the non-sterile conditions, which could alter the performance of the media.

Agar, a solidifying agent found in solid media formulations, allows for easy visualization of bacterial colonies. Typically, after media preparation and before sterilization, the substance is stored and handled to prevent contamination and deterioration. Both the physical integrity and nutritional content of media should be maintained, preserving its capacity to support bacterial growth until use. However, for best practice and optimal results, minimize the time between media preparation and sterilization, keeping the non-sterile media in the fridge for the minimal possible time.