Now that outdoor temperature is dropping, do you still need to ship agar media plates with ice packs?

When we receive agar plates (MEA, TSA, DG18) from manufacture, they are never shipped with ice packs. Ice packs can cause condensation to occur inside of agar plates. Free water flowing around and going in and out of plates is a major cause for contamination. When laboratory ship agar plates out, there is no need for ice packs either. Remember, media agar is sterilized at 121 degree C and kept at 60 degree C for 1 to 2 hours during preparation. Chemically, most agar plates are stable at room temperature for several days to several weeks. Microbiologically, they cannot go bad (grow germs) because they are sterile unless they were contaminated.

Contamination should be very rare in laboratories that check for sterility twice (once upon receiving and once before shipping out). It's recommended to have agar plates individually wrapped and sealed using breathable material. Electrical tapes, Scotch tape, and painter's masking tape are not breathable. After you receive agar plates, they should be kept in a paper box (or bag) placed on the middle shelves (not top or bottom) at a refrigerator for long term storage (if not to be used within 2 days). This will avoid contact by insects and reduce agar-drying while minimizing condensation.

After collecting samples, agar plates should arrive in the lab within 48 hours. There is no need for ice packs if the agar plates can arrive in the lab within 48 hours and the temperature during transport is below 40 degree C. If the retention time is longer than 24 hours before you can ship them out, they should be kept in a refrigerator at the conditions described above for up to 2 days.

Coolers are good for carrying things to the job sites or the picnic park. They can be difficult to be sealed for shipping, and the top cover is usually poorly insulated. They also get charged with extra shipping fee for not being in a cardboard box. It's recommended to use an insulated box (uline.com: S-12682) for shipment. Pack plates in a paper box or paper bag (not plastic bags) and place them in the insulated container. If ice packs are needed, insulate the ice pack with bubble envelope (or wrap) to avoid condensation to accumulate inside agar plates. Ice cubes in a plastic bag is not a good choice because a lot of water will leak out. Provide enough cushion material including some paper to absorb possible condensation from ice packs.

We have been helping companies that were frustrated with unsatisfying services from their microbiology labs on issues such as:
(1) poor technical support
(2) no personal attention
(3) questionable results
(4) project delay; slow turnaround time
(5) reports not making sense
(6) lack of ethics

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Host: Joe Hughes/Cliff Zlotnik

Episode Notes: This week we welcome Tom Neltner, JD, CHMM Director of Training and Education for The National Center for Healthy Housing. We will continue our discussion of Home Health Assessments and talk about the new Health Homes Certification. There is a lot more to healthy homes than mold and moisture and we will get into the numerous issues investigators, remediators and others should be aware of when dealing with residential properties and occupants.

Scheduled Time:
Date: Fri, October 10, 2008
Time: 12:00 PM EDT