The disk must be stored properly. For working supply, disk must be refrigerated at 2°C to 8°C for at least 1 week. For long term storage, the disks are stored at −20°C or below in a non–frost-free freezer. The disk should be properly stored in a tightly sealed container with desiccant. To prevent condensation formation on the disks, which happens when warm room air contacts the cold disks, it should be allowed to warm to room temperature before it is opened.

Source: Mahon, C.R, Lehman, D.C, & Manuselis, G. (2015). Textbook of Diagnostic Microbiology, Fifth Edition. Maryland Heights, Missouri: Elsevier

In accordance to Mahon (2019, p. 278), the following are the guidelines for storing disks that will be utilized for disk diffusion:

1. Temperature for long-term storage: −20° C or below (in a non-frost-freeze freezer)

2. Temperature for storing working supply of disks for at least a week: 2° C to 8° C

3. Container storage: Tightly sealed with desiccant, warmed in room temperature before opening to prevent condensation

Source credit:

Mahon, C. R., & Lehman, D. C. (2019). Textbook of diagnostic microbiology (6th ed.). St. Louis, MO: Elsevier Saunders.

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