Our lab buys 500 mL bottles of RPMI-1640 Medium and stores them at 4C. Oftentimes, for my experiments, I only need about 100 mL total. So, I will make RPMI-1640 + 10% FBS with 90 mL of media and 10 mL of FBS. Then, I always tightly wrap parafilm around the remaining 400 mL of media and put it back in 4C.
- Is the media still good?
- What is the shelf life of the media after it has already been opened in a hood?
- Can I come back, say in 3 months, and use another 100 mL from the opened bottle?
Hello Gage,
The answer to all your questions is as follows.
The bottle of RPMI-1640 medium should always be refrigerated and protected from light. Once the seal is broken, and some of the media is used, the lid needs to be sealed immediately to avoid exposure to air. The RPMI preservative will start to degrade once exposed to air. RPMI medium that turns bright pink should be discarded.
Even though there is an expiration date on the bottle, a much better indication is the color of the medium. Fresh medium is peach colored. As the medium oxidizes it changes in color from peach to bright pink. The medium is still good when it is pink but should not be used when it is a very bright pink.
Best.
3 month can be done. Much longer than that I'd aliquot & freeze once. Or just buy it new & sleep better.
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