Storage instructions that are stated on all product labels should be observed at all times. All plated media and some tubes and bottles are to be refrigerated at 2 to 8 degrees C. immediately upon arrival in the laboratory. Refer to the cautions listed in the "Problem Reporting" section. The ASM's Clinical Microbiology Procedures Handbook recommends setting the refrigerator at 6 degrees C., and allowing it to fluctuate no more than 2 degrees C.(20)
Always allow media to warm up to room temperature before inoculating. This minimizes "thermal shock" to the bacteria.
Do not freeze or overheat culture media unless specifically indicated in the technical insert. Do not incubate media prior to inoculation (except briefly to evaporate excessive surface moisture).
Storage temperature must be carefully monitored on a daily basis. Do not store media adjacent to the freezer compartment of the refrigerator. Agar or blood containing media that has been frozen even for brief periods of time must be discarded.
Do not store dry ice in a refrigerator used for media storage. The dissipating CO2 will cause a harmful pH shift in the media.
All plated media should be stored in the original unopened bag. Previously opened bags should be re-sealed. Twist-ties are available upon request.
Plates should be stored in the inverted position to prevent moisture from contacting the surface.
Media should never be exposed to sunlight or UV light, since many ingredients, especially dyes and indicators, are not stable upon exposure. Media should be stored in a dark environment. Excessive exposure to light can result in the formation of peroxides that are toxic to bacteria.
Media stock must be rotated to ensure that the oldest media is used first.
The expiration date applies only to unopened packages that have been stored as directed. Do not attempt to use media beyond the expiration date stated on each package.