CMS SOM App. C, Tag D5477

(e)(4) Before, or concurrent with the initial use--

(e)(4)(i) Check each batch of media for sterility if sterility is required for testing;

(e)(4)(ii) Check each batch of media for its ability to support growth and, as

appropriate, select or inhibit specific organisms or produce a biochemical response;

and

(e)(4)(iii) Document the physical characteristics of the media when compromised

and report any deterioration in the media to the manufacturer.

Interpretive Guidelines §493.1256(e)(4)

A batch of media (solid, semi-solid, or liquid) consists of all tubes, plates, or containers

of the same medium prepared at the same time and in the same laboratory; or, if received

from an outside source or commercial supplier, consists of all of the plates, tubes or

containers of the same medium that have the same lot numbers and are received in a

single shipment.

A sample from each batch of media is sufficient as a check for:

• Sterility, if it is autoclaved or filtered during preparation;

• Ability to support growth, using at least one organism to demonstrate the ability

of the media to support growth;

• Selectivity and/or inhibition, using at least one organism to confirm its selective

characteristic, and at least one organism to confirm its inhibitory characteristic;

and

• Biochemical response, using at least one organism which will produce the

expected reaction (positive control) and with at least one organism which will not

produce the expected reaction (negative control).

American Type Culture Collection (ATCC) control organisms are not necessarily

required. However, if the laboratory uses “in-house” isolates for control organisms, it

must have established reactivity for each organism. Use D5469 as appropriate.

Central laboratories that prepare media for satellite locations must either perform the

same quality control checks required of commercial manufacturers and furnish

documentation of media quality control checks to each satellite location, or each

laboratory must continue to perform media checks as required under §493.1256(e)(4).

If a laboratory screens cultures for growth or no growth, reports “No growth” and refers

all growth to a reference laboratory, the screening laboratory must perform applicable

quality control of the media.