I have found a batch of trypcase soy broth supplied sterile which in unopened jars stored at 2-8'C has particles in it readily observed with the naked eye. These settle to the bottom of the jar until swirled, so must be a reasonable size. The remainder of the broth appears clear, so I am not too concerned that it is contamination by microorganisms. This remains the case following aliquotting and incubation for 7 days at 37'C.

Could it be a component precipitating out of solution? I haven't observed this in other lots from the same supplier.