DESCRIBE CULTURE MEDIA

Culture media, also known as growth media, are specific mixtures of nutrients and other substances that support the growth of microorganisms such as bacteria and fungi (yeasts and molds).

 

Culture media are used for quality control tests of nonsterile raw materials and finished products as well as for microbial contamination (sterility) tests in applications such as hygiene monitoring, sterilization process validation and determination of the effectiveness of preservatives and antimicrobial agents.

 

The culture media ingredients vary according to the test being performed and the microorganism of interest. Most commonly, culture media are based on a nutrient broth (liquid), often mixed with agar and prepared in petri dishes (they may be semi-solid or solid). For enriched or selective media, further specific components are added.

 

Culture media preparation must be carried out accurately to ensure microbiological growth is correctly promoted. The individual ingredients of the culture media (powders, gels and liquids) must be carefully weighed out according to the culture media formulation recipe. A precision balance with readability from 1 mg up to 10 mg is typically used for the main components. An analytical balance may be required for weighing out trace elements such as copper and zinc. If a smaller amount of culture media is required, care must be taken to correctly recalculate the ingredient quantities and a balance with a higher readability may be required in order to fulfil accuracy requirements.