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://cfsan.fda.gov 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
after 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
using 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
and 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:
A. a common milker claw is used for abnormal and then normal milk,
Or
B. 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. PMO-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.
1
M-I-00-07 1 August 11, 2000
