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M-I-00-07: Questions and Answers from Milk Specialists Conferences

<< Back to Index of Memoranda of Information (M-I) Main page
 

HHS:PHS:FDA:CFSAN:OC:DCP:MSB

200 C Street, SW
Washington DC

M-I-00-07

August 11, 2000

TO: All Regional Food and Drug Directors
Attn: Regional Milk Specialists

FROM: Milk Safety Branch (HFS-626)

SUBJECT: Questions and Answers from Milk Specialists Conferences

Following are the questions and answers from the Milk Specialists Conferences held in San Luis Obispo, CA in June of 1996 and Harper's Ferry, WV in May 1998.

In accordance with procedures established through the National Conference on Interstate Milk Shipments, if an answer to these questions results in a new understanding of a long-standing situation or installation, and the condition as it exists does not present a public health hazard, reasonable judgement should be exercised, and adequate time provided for modification and correction.

Copies of this memorandum are enclosed for distribution to Regional Milk Specialists, State Milk Regulatory Agencies, State Laboratory Evaluation Officers and State Milk Sanitation Rating Officers in your region. This memorandum is also available on the FDA Web site at http://ww.fda.gov/food and should be widely distributed to representatives of the dairy industry and other interested parties.
 

Joseph M. Smucker, Chief
Milk Safety Branch
 

QUESTIONS AND TECHNICAL ISSUES

FDA Milk Specialist's Conference
Harper's Ferry, WV

June 2 - 4, 1998

Following are questions and answers (in Italics) from the Milk Specialists Conference in Harper's Ferry, WV

  1. PMO-Section 1

    A state regulatory agency received a request from a cultured dairy food processor to allow burst rinsing of culture vats containing pasteurized product fter the majority of the product has been removed from the vat. This rinse water contains products such as yogurt or sour cream solids that are cooled to less than 45°F and stored in sanitary equipment. It is then standardized for use in cottage cheese dressing. Is this an allowable practice?

    Yes. The rinse water and product must be properly handled and the cottage cheese dressing must be pasteurized. The burst rinsings are considered to be raw (because of the unpasteurized water) and must not be cross-connected with pasteurized product or pasteurized product contact surfaces.

  2. PMO-Section 1 and 4

    Is the practice of reconstituting nonfat dry milk powder with water for addition to cultured products for adjusting solid's content acceptable when the term "reconstituted" or "recombined" is not declared on the label for the Grade "A" product?

    That depends on the standard of identity for the product. Because part of the standard of identity for yogurt has been stayed, at this time it could be made from reconstituted dry milk powder without the term "reconstituted" or "recombined" being used. The standard of identity for cottage cheese and cottage cheese dressing also would allow for the use of reconstituted dry milk. No other Grade "A" product standard of identity we are aware of provides for this practice. The addition of water would result in a product that did not meet the standard of identity, and could not be labeled with a standard name.

  3. PMO-Section 1 and Section 7

    Can C02 (carbon dioxide) be used in packaging fluid milk?

    FDA has not accepted the addition of CO2 to milk in the packaging process. The addition of CO2 to milk is not provided for in the standard of identity for milk.

    CO2 is presently added to cottage cheese in the packaging process. It is a preservative gas because it extends the lag growth phase of bacteria. Is this a violation of Section 7 of the PMO?

    No. The practice of incorporating CO2 into cottage cheese has been accepted for several years. This acceptance was for cottage cheese only, and a review of the safety of the process or of compliance with the standard of identity for other dairy products has not been made.

  4. PMO-Section 6

    Many states ask industry to send the samples (and pay for analysis) for vitamin assay? What should this process be?

    M-a-93 states: "All plant sampling for regulatory purposes shall be by the regulatory agency, except samples for vitamin analysis taken under the direction of the regulatory agency." FDA does not object to states requiring that processing plants pay for the vitamin analysis.

  5. PMO-Section 7, Item 8r and Appendix D

    Is the water coming out of the pre-cooler, used on dairy farms, potable water or non-potable water?

    Water from pre-coolers may be used for milkhouse purposes if the requirements from Appendix D., VI.-Water Reclaimed from Heat Exchanger Processes, Items #1 - 10 of the PMO are met.

  6. PMO-Section 7, Item 15p(B)

    A firm is pushing pasteurized dairy product to tanker trucks or product tanks sing well water. Is this a 15p(B) debit?

    Yes. The PMO accepts pushing pasteurized products with water that has undergone a process equivalent to pasteurization that has been found acceptable to FDA and the State Regulatory Authority.

  7. PMO-Section 7, Item 15p(B)

    Does the water used to push pasteurized product to storage tanks or to tanker trucks have to be pasteurized in a legal HTST unit or can it be heat treated in a non-legal plate heater or vat? If a non-legal system is acceptable, what are the minimum time and temperature requirements that must be met and what records charts, testing, etc.) are needed?

    No. If the water is heated but not in a legal pasteurization system, adequate documentation must be available to show the water has been subjected to the minimum times and temperatures required for pasteurization.

  8. PMO-Section 7, Item 15p(B)

    How long can pasteurized water be stored and still be used to push or flush pasteurized product to tanks or trucks? Does the water need to be maintained at a temperature below 45° F or is ambient temperate acceptable? Do we need cooling charts? Does the storage tank or silos need a record showing the frequency of cleaning? If the water is stored more than 24 hrs, does the state need to sample nd bacteriologically test the water?

    Pasteurized water may be held at any temperature, provided it's adequately protected. We have accepted 24 hour holding times for pasteurized water held at temperatures within bacterial growth ranges. There is no requirement for cooling charts or water tank cleaning records. We have not required any additional sampling of this water.

  9. PMO-Section 7, Item 15p(B)

    May water, treated with a sanitizing agent, be used to push pasteurized product to storage tanks or trucks?

    Does the push water need to contain the chemical sanitizing agent at a legal sanitizing solution level or is a lower level acceptable? What is the lower acceptable level? Are all types of sanitizing agents acceptable for this type of use? Must the sanitizing agent used meet EPA standard as an acceptable chemical sanitizing agent? Is there any chemical sanitizing agents that cannot be used for this purpose?

    Until we have further information about sanitizers involved (strengths, characteristics and adulteration factors) and the system involved, the use of chemically treated water in contact with pasteurized products is a violation of 15p(B) 2.

  10. PMO-Section 7, Item 15p(B)

    If a firm uses water to push/flush raw milk products to tanks, silos or trucks is it acceptable/ required to use a manually operated block and bleed valve arrangement to separate a permanent water connection to a product line or valve cluster? Is it required to have a vacuum breaker on the water line that is connected to the raw product line?

    The PMO requires that, except when actually flushing lines with water, there be sufficient separation between water piping and unpasteurized dairy products or lines used to conduct unpasteurized dairy products, to prevent the accidental addition of water. A physical break, such as a swing elbow to a pipe connection, can be used. An arrangement of valves and piping in a block and bleed type configuration can also be used, provided that, when challenged, the arrangement can be demonstrated to prevent accidental addition of water when one or more of the valves fail.

    Effective means, including an adequate air gap or a sanitary check valve and appropriate backflow preventer, shall be provided to protect the water system in the event of back siphonage from or backpressure into the water system.

  11. PMO-Section 7, Item 16p(d)

    A milk processing plant has a raw line entering the pasteurization unit between the balance tank and booster pump.

    What are the requirements for this system?

    This is a violation of 16p(d)-Regenerative Heating if the system has a product-to- product regenerator.

    To be acceptable, any vessel feeding the line between a HTST balance tank and booster pump must meet the height and overflow requirements for a HTST product balance tank.

    The information given in this question represents an isolated element of a pasteurization system. Without a complete system drawing we cannot determine the acceptability of this pasteurization system design.

  12. PMO-Section 7, Item 17p

    Can Grade "A" cottage cheese be filled "hot" (over 45° F)? The PMO clearly states that pasteurized milk and milk products except those to be cultured, are cooled immediately to 45° F or less in approved equipment"

    FDA has evaluated one "hot fill" process for cottage cheese and accepted the practice as safe. Any new processes or variations of the process should be evaluated on a case-by-case basis.

  13. PMO-Section 7, Item 17p

    If a product is a potentially hazardous food such as Leben (kosher yogurt) with a culture that won't allow the pH to drop lower than 5.1, can the product be packed at 80°-120° F? If allowed, how long before the product must be cooled to 45°F or less?

    The PMO exemption from the requirement for immediate cooling of products after pasteurization has normally been applied to cultured products with a pH of 4.6 or less because the targeted pathogens are not active in that pH range. The safety of the process described above has not been reviewed or established. More information is necessary in order to evaluate this practice.

  14. PMO-Section 11 and Procedures-Section VI

    If a milk processing plant is found by FDA to be shipping products in interstate commerce and has not been rated or listed in accordance with the IMS program, can FDA act as a third party and require the shipping state to rate and list the plant?

    No.

    What are the consequences for the state and plant if a state does not rate or list a plant that is shipping Grade A product interstate?

    FDA will request the receiving state(s) to follow Section 11 of the PMO.

    This situation will also be noted in a FDA State Program Evaluation of both the shipping and receiving State(s).

    A dairy plant in interstate commerce, not regulated under the Interstate Milk Shipper Program, will be regulated under the Federal Food, Drug and Cosmetic Act.

  15. PMO-Section 7, Appendix N

    Do the requirements for 10% tanker sampling and record audit by the State Regulatory Agency at sites receiving Grade "A" raw milk directly from farms apply to both IMS and Non-IMS plants, transfer stations and receiving stations?

    Yes.

  16. Procedures-Sections IV and V

    What do the current Procedures state about time periods before a new rating following a failed FDA Check Rating or State Rating that scores less than 90%?

    Check Rating: New ratings may be made when the State Rating Agency has reason to believe a new rating would result in an acceptable rating. (See Procedures, Section IV., B.6.c.1.C and Section IV., B.6.c.2.C).

    State Rating: A re-rating shall be conducted when the State Rating Agency has reason to believe a new rating, would after written notification from an authorized representative of the IMS Listed shipper to the rating agency that the IMS Listed shipper is in substantial compliance. A re-rating shall be completed in no more than fifteen (15) days from the date of the receipt of the notification, unless the state rating agency has a reason to believe a new rating within a lesser time would result in an acceptable rating. (See Procedures, Section V., I.2.)

  17. DMO-Section 7, Item 7p and Appendix D

    According to the DMO, cow water meeting Water Reclaimed from the Condensing of Milk and Milk Products, Items 1-12 may be used for all potable purposes.

    May cow water be used to re-constitute various milk powders and stabilizers used to produce food products?

    Yes. It must be organoleptically suitable and the reconstituted product must be pasteurized.

    Can cow water be used to rinse the residue cheese curd from double "O" tanks or push/flush raw or pasteurized product to storage tanks or tanker trucks?

    Yes. It must meet Appendix D, V., items 1-12 of the PMO.

    If cow water is used to rinse equipment or lines, the rinsings are considered raw and must be handled accordingly. If line rinsings are to be used as an ingredient in a standardized food, care must be taken that such addition is in accordance with the standard for the food involved.

    If cow water is used to push pasteurized product, it must be documented that the cow water has been pasteurized or has undergone an equivalent process acceptable to the State and FDA.

    If acceptable, do we need a vacuum breaker and a block and bleed valve arrangement on any permanent cow water connections?

    Effective means, including an adequate air gap or a sanitary check valve and appropriate backflow preventer, shall be provided to protect the water system in the event of back siphonage from or backpressure into the water system.

    Can a conductivity meter be used in place of a turbidity meter?

    Yes. It must be calibrated to detect and respond to an organic content of less than 12 mg/liter as measured by Chemical Oxygen Demand (COD) or the Permangate Consumed Test. (See Appendix D, V., Item #3).

    When cow water is used in the boiler to generate culinary steam, does the cow water have to comply with items 1 - 12 or 3 - 11 and a-d if the culinary steam is used to heat potable water to sterilize product lines?

    Satisfying either set of requirements is acceptable.

    For emergency purposes, it has been acceptable to have a raw water connection to a pasteurized product feed line to an evaporator unit; the emergency water (ready water) is usually stored in a tank.

    Should we start requiring this ready water to be pasteurized or to contain a sanitizing agent?

    No.

    Is it acceptable to use cow water for this purpose?

    Yes, if it complies with Appendix D., Water Reclaimed from the Condensing of Milk and Milk Products, Items 1-12 of the DMO.

    Are any other requirements in addition to those already being done on the cow water, stored in the main silo/tank or cow water stored in a ready water storage tank? These requirements could include the length of time the water can be stored; daily cleaning/sanitization; testing requirements; etc.

    No.

  18. DMO-Section 7, Item 15p(B)

    In an evaporator condensing unit, cow water is generated and fed to a balance tank, (which effectively separates any cross connection). From the balance tank the cow water goes to the plate pre-heater and heats up incoming raw milk on the other side of a thin walled plate. It then exits the plate heat exchanger and goes to a turbidity meter and if OK, to a storage tank. Since the DMO says it must go to the turbidity meter first, is this system acceptable?

    If both sides of the plate heat exchanger and associated piping are cleaned after each use, we do not believe there is a public health issue involved, and while this may be a technical violation, it is an acceptable system. See the Journal of Milk and Food Technology, Vol. 29, #2, Pages 40-44.

    QUESTIONS AND TECHNICAL ISSUES

    FDA Milk Specialist's Conference
    California Polytechnic State University
    Dairy Products Technology Center

    San Luis Obispo, CA

    June 9-14, 1996

    Following are questions and answers (in Italics) from the Milk Specialists Conference San Luis Obispo, CA

  1. PMO-Section 7, Item 1r-Abnormal Milk

    Why is it not debitable on a check rating to mark abnormal milking practices when a separate vacuum source is not present, no separate claw is available, and yet you verify the dairyman milked treated cows in the middle of the milking string?

    It is a violation of Item 1r-Abnormal Milk, debitable on the inspection sheet under Item 1(a), to milk cows giving abnormal milk during the milking of the cows giving normal milk if:

    1. a common milker claw is used for abnormal and then normal milk,

      Or

    2. the milk line to the bulk milk tank, or a vacuum line directly connected to this milk line, is used to provide vacuum directly to the bucket or pail type milker used to harvest abnormal milk.

      These practices can be debited without direct observation if they can be confirmed by other direct means, such as observing a used abnormal milking bucket with no separate claw in the milking area during milking.

      These violations should not be debited based only on statements by owners or other individuals.

  2. PMO-Section 7, Item 2r-Floors and Walls/Ceilings

    Are feed troughs of concrete etc. which are in poor repair an Item 2r(a)-Floors violation; whereas, poor repair of hanging feeders is an Item 2r(b)-Walls and Ceilings violation?

    Yes.

  3. PMO-Section 7, Items 3r-Milking Area-Cleanliness, 6r-Milkhouse-Cleanliness, 10r-Equipment-Cleaning

    Are dirty air injection hoses debited under inspection sheet Item 3, 6, 10, or 10 and 11?

    If the inside of these hoses are soiled enough to debit, they would be evaluated under Item 10r. If the outside is soiled they could be evaluated under Item 3r or 6r depending on where they are located.

  4. PMO-Section 7, Item 5r-Walls and Ceilings

    Is exposed wood such as door framing and raw wooden racks etc. debited under Item 5r-Walls and Ceilings?

    Yes. Such unfinished wood may be debited under Item 5r-Walls and Ceilings.

  5. PMO-Section 7, Item 5r-Walls and Ceilings

    Are "smashed" hose ports debited under Item 5r-Walls and Ceilings (b) or 5r-Miscellaneous Requirements (d)?

    5r-Walls and Ceilings (b). The hose port is present but it is not in good repair.

  6. PMO-Section 7, Item 8r-Water Supply

    Are standard flush toilets submerged inlets?

    No.

  7. PMO-Section 7, Items 18r-Raw Milk Cooling and 17p-Cooling of Milk

    Is it acceptable to leave raw milk outside the temperature zone (above 45 degrees F.) for periods over four hours?

    No. It is also unacceptable for raw milk to be above 45 degrees F. for less than four hours unless specifically provided for by the PMO and related documents.

  8. PMO-Section 7, Item 5p-Separate Rooms

    If a milk plant is over crowded is it debited under 5p(a)?

    Yes.

  9. PMO-Section 7, Items 10p/11p-EquipmentCleaning/Sanitizing, Item 12p-Equipment Cleaning/Sanitizing and Appendix B-Milk Sampling, Hauling and Transportation

    Do bulk milk pick up tankers have to be washed after each load (usage)? Can they be washed once a day?

    No. Yes.

  10. PMO-Section 7, Item 14p-Storage of Single-Service Articles

    If jugs (single service plastic milk bottles) are received in ripped up bags, is this not a violation of 14p(a)?

    Yes.

  11. PMO-Section 7, Item 15p(A)-Protection from Contamination

    Is a water rinse allowed on pasteurized product surfaces in a milk plant between pasteurized products?

    Currently two options are allowed:

    Option 1: Rinsing with pasteurized water, or

    Option 2: Rinsing with water containing an acceptable sanitizing solution provided that the sanitizer is completely drained from the equipment before product is brought back.

    Other alternatives may also be allowed after they have been reviewed by FDA and found acceptable by FDA and the States.

  12. PMO-Section 7, Items 15p(A)-Protection from Contamination and 19p-Capping

    Is it a partial debit against the filler volume when one finds a 10-gallon can over temperature, or is it a cooling debit?

    Out of temperature milk or milk products collected from defoamers or otherwise drained or rinsed from equipment, for reuse in Grade A products, is evaluated under Item 15pa(a). This item is not prorated.

    Out of temperature milk or milk products dumped from partially filled or imperfectly closed containers, for reuse in Grade A products, is evaluated under Item 19p(b). This item is prorated by filler volume when calculating a rating/check rating score.

  13. PMO-Section 7, Item 15p(A)-Protection from Contamination

    What are the standards for or definition of "pasteurized" orange juice, etc., when a one-valve separation is allowed?

    If the times and temperatures used to pasteurize the orange juice are at or above those used to pasteurize milk, one valve separation from pasteurized milk is allowed.

    Lack of state testing or deviations from milk pasteurizer construction or operating requirements is not sufficient to consider orange juice unpasteurized unless it can be demonstrated that the juice has not been subjected to the intended times and temperatures.

  14. PMO-Section 7, Item 16p(B)-Pasteurization-High Temperature: Time and Temperature Controls

    Do valve out valves on a separator valve out system have to be position detectable (visually can be seen)? There are still closed yoked valves in use that have a hole for leak detection between the valve seat and actuator and one can not see the valve position.

    Valves used to "valve out" a separator in a continuous flow pasteurization system must fail to the valved out position, and when tested must move as required. There is no specific requirement that they be visually position detectable.

  15. PMO-Section 7, Item 16p(B)-Pasteurization-High Temperature: Time and Temperature Controls

    Do mag flow transmitters need to be sealed by the regulatory agency?

    In traditional hard-wired systems, no regulatory seal is required on the transmitter.

    Computer based milk pasteurization controls, including microprocessor based magnetic flow meter transmitters, must comply with M-I-88-11.

    Therefore if public health parameters can be changed at a micro-processor controlled transmitter in a magnetic flow meter based timing system, the regulatory agency must verify that the correct program is in place then seal the transmitter to prevent unauthorized changes.

  16. PMO-Section 7, Item 16p(D)-Regenerative Heating

    Are vacuum breakers, installed so that they do not work, a violation. If so, please explain how disk/black rubber vacuum breakers work? How about Teflon ones that are on the hot side and swell up and then never work? Are these good?

    None of the M-b equipment evaluations for vacuum breakers (M-b-95, M-b-95 supplement 1, or M-b-311) speak to the disk/black rubber type vacuum breaker, which you describe. Vacuum breakers must respond to a negative pressure by creating an opening to the atmosphere. If it can be verified that this does not happen, it is in violation and must be evaluated accordingly.

  17. PMO-Section 7, Item 16p(D)-Regenerative Pressure

    Is it acceptable to place an incoming raw milk line between the constant level tank and the booster pump, or does the milk have to go to the constant level tank first?

    In HTST systems with regenerators, the incoming raw milk or milk products must not, under any circumstances, be able to exert pressure on the raw side of the regenerator during a shut down. It is virtually impossible to assure this unless the raw milk enters the system through the constant level tank.

  18. PMO-Section 7, Item 16p(E)-Temperature Recording Charts, Equipment Tests and Examinations

    Are PMO "holding time tests" required for aseptic systems?

    No.

  19. PMO-Section 7, Item 17p-Cooling of Milk

    Is cooling tower water OK for buttermilk cooling?

    No.

  20. MO-Section 7, Item 18p-Bottling and Packaging

    Is condensate on mandrels of fillers a filling debit? How much is too much?

    Yes. How much is too much is a matter of professional judgement.

  21. PMO-Section 7, Item 18p-Bottling and Packaging

    Is it acceptable to allow operators to drink at the filler if they have a covered, dedicated bottle?

    No.

  22. PMO-Section 7, Item 19p-Capping

    Are caps supposed to be able to be removed from milk jugs without detection?

    No. If this is observed please advise the state rating and regulatory agency and Milk Safety Team in writing. At present do not debit for this item during ratings or check ratings.

  23. PMO-Appendix J-SSCC, Section A-Purpose

    What are the RMS options for action concerning the state listing of a single service container manufacturing plant when that plant is nowhere near compliance?

    Under the conditions described, an FDA regional Milk Specialist has the option not to endorse the state "Report of Certification..." Form FDA 2359d.

  24. PMO-Appendix J-SSCC, Sections C-Bacteriological and D, Item19-Wrapping and Shipping

    Do plastic bags that jugs (single service plastic milk bottles) are packaged in have to have letters confirming compliance with 21 CFR and bacteriological results? How often are these results required?

    All packaging materials that contact the product contact surface of single service containers or closures must comply with the requirements of parts 175 through 178 of Title 21 of the CFR and the bacteriological standards in Section C of the "Standards for the Fabrication of Single Service Containers and Closures for Milk and Milk Products".

    There is no required bacterial testing frequency for materials used to package single service containers.

  25. PMO-Appendix J-SSCC, Sections C-Bacteriological and D, Item19-Wrapping and Shipping

    Are cardboard dividers allowed in boxes of milk cartons? We do not allow them in milk jug bags, but we do in milk carton boxes.

    Many cardboard dividers are unable to meet the bacterial standards that are required if they touch product contact surfaces of the single service containers. In the case of plastic milk bottles they normally touch the pouring lip when single service plastic milk bottles are packaged in double layers with cardboard dividers between the layers.

    In the case of flat folded milk carton blanks, which are packaged in card board boxes with card board dividers, neither the card board box nor the card board dividers touch a product contact surface of the carton blanks.

  26. PMO-Appendix J-SSCC, Sections C-Bacteriological and D, Item 19-Wrapping and Shipping

    Does a single service container manufacturer have to place a plastic liner in a card board box before packing single service plastic milk bottles in it?

    In most cases a liner is needed in order to meet the requirements of the "Standards for the Fabrication of Single Service Containers and Closures for Milk and Milk Products".

  27. PMO-Appendix J-SSCC, Section D, Item 20-Identification and Records

    Do single service jugs have to have plant identification on the outside of the container? Is it acceptable to emboss the clear plastic bag with the plant name and identification even if during the inspection no one can easily find it including plant management?

    If the labeling on the outer wrap is inadequate, it should be improved. Only the outer wrapping must be labeled with the identification of the plant where the single service containers were fabricated (see Item 20(a) in the Standards for the Fabrication of Single Service Containers and Closures for Milk and Milk Products). The individual jugs (or any other type of single service Grade A dairy product container) are not required to bear this identification.

    TECHNICAL ISSUES

    (Editorial license was used to summarize the questions)

    Technical Issues 1 and 2: PMO-Section 7, Item 16p(D)-Regenerative Pressure

    These issues involve standardizing or blending on the raw side of an HTST pasteurizer.

    See Q&A #17. In addition, no product may enter or leave the system between the timing pump and the flow diversion device.

    Technical Issue 3: PMO-Section 7, Item 8r-Water Supply

    With regard to the Germania milking machine back flushing system, why are the water, sanitizer and product connections not considered to be a cross connection.

    Because of a movable block type construction, when the Germania back flush system is milking cows or is in the "rest" position between cows, the water and sanitizer connections are moved providing a complete physical break to atmosphere between them and the milk line. Any modification of this equipment that does not include such a physical break is unacceptable.

    The iodine and water lines will most probably be directly connected to each other. When this is true, if the iodine (or other acceptable sanitizer) is dispensed from a container that is larger than one gallon, there will need to be an appropriate back flow preventer on the water line upstream from the connection to the sanitizer line to protect the water supply from the sanitizer.

    Technical Issue 4: PMO-Section 7, Item 16p(D)-Regenerative Pressure

    In a HTST pasteurization system, can a pressure relief valve and line be located between the flow diversion device and the inlet to the pasteurized side of the regenerator?

    The pressures in the pasteurized side of the regenerator must be protected from falling within one pound of the pressures in the raw side of the regenerator at all times, including during shut down.

    A relief valve and line in this location can meet this criterion if:

    at some point after the relief valve and before the entrance to the pasteurized side of the regenerator all product rises at least one foot higher than the highest raw milk in the system, and is open to the atmosphere at that point.

    OR

    the pressure relief valve is spring loaded and plumbed so that it cannot be opened or forced open in any mode (product, CIP, or, inspect) without the assistance of pressure from the liquid flowing through the system.

    In the latter case, a leaking pressure relief valve can cause an unacceptable loss of pressure in the pasteurized side of the regenerator during a shut down and is in violation.