200 C Street, S.W.
Washington, DC 20204
August 15, 1995 (issued)
October 15, 1995 (effective date)
TO: All Regional Food and Drug Directors Attn: Regional Milk Specialists
FROM: Acting Chief, Milk Safety Branch, HFS-626
SUBJECT: Questions Relating to the use of Ball Type Sanitary Check Valves in HTST, HHST and Aseptic Processing Systems
PMO, SECTION 7, ITEM 16p(B).2.f., FOR HTST AND HHST AND 16p(C).2.c., FOR ASEPTIC--FLOW PROMOTING DEVICES
May ball-type sanitary check valves be used as the positive shut- off, required by the PMO, between the flow diversion device and the pasteurized side vacuum equipment in a continuous flow pasteurization system?
A. No. A ball-type check valve will only assume the blocked (shut- off) position when pressure for forward flow, in the pipe, is reversed. In this application the positive shut-off must protect the flow diversion device against vacuum equipment located downstream. A ball-type check valve located between a flow diversion device and downstream vacuum equipment would be held open by vacuum from the downstream equipment and therefore, cannot provide the needed public health protection.
PMO, SECTION 7, ITEM 16p(D), -- PASTEURIZED OR ASEPTIC PRODUCT IN REGENERATOR AUTOMATICALLY UNDER GREATER PRESSURE THAN RAW PRODUCT AT ALL TIMES
May ball-type sanitary check valves be used as the positive shut off required by the PMO before and/or after vacuum equipment located on the pasteurized side of continuous flow pasteurization systems which contain product-to-product regenerators or which contain (raw) product-to-water-to-(pasteurized) product regenerators which are protected on the pasteurized side?
A. Ball-type sanitary check valves may be used as the required positive shut-off when they are located after the vacuum equipment. Ball-type sanitary check valves shall not be used to provide the required positive shut-off before such vacuum equipment (see previous answer).
PMO, SECTION 7, ITEM 16p(B).2.f., -- FOR HTST AND HHST AND 16p(C).2.c., -FOR ASEPTIC--FLOW PROMOTING DEVICES
May a ball-type sanitary check valve be used, as the required check valve, after an A-C variable drive centrifugal pump in a magnetic flow meter based timing system?
NOTE: Any PMO required positive shut-off found to leak is no longer considered in compliance (applicable to the above three questions).
This interpretation was issued in accordance with the guidelines for issuance of interpretations and was distributed to all state milk regulatory and rating officials for comment. Comments received by the NCIMS Executive Secretary were considered by the NCIMS Executive Board and the FDA and were incorporated into this document when it was agreed to be appropriate. This memorandum is effective on October 15, 1995 (60 days from the date of issue).
Copies of this memorandum are enclosed for distribution to State Milk Regulatory Agencies, State Milk Rating Officers and District Milk Specialists in your region. This memorandum is also available on the FDA Prime Connection computer bulletin board system and should be widely distributed to representatives of the milk industry and all other interested parties.
Joseph M. Smucker, Acting Chief
Milk Safety Branch
Center for Food Safety and