M-I-84-4: Recent Seminar Discussions


200 ~C~ Street,
D.C. 20204


April 20, 1984

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

From : Milk Safety Branch, HFF-346

Subject: Recent Seminar Discussions

Enclosed are copies of the questions and answers which were discussed at Region I and II Seminar held in 1983.

Copies of this memorandum are enclosed for distribution to State milk sanitation regulatory agencies and State Milk Rating Officers in your Region.

Robert L. Sanders
Senior Milk Sanitation Officer


Questions and Answers from the Region I and II Milk Seminar:

1.Q: Does Test #22, swab and rinse procedure, cover coliform for single-service containers?

A: Yes.

2.Q: Does a submerged inlet in a stock trough at the bottom of a hill and downhill from the milk house need to be protected against back siphonage if there is no pump in the system? (gravity system)

A: Each system must be evaluated individually to determine other unstated factors, such as the likelihood of the occasional use of a high pressure cleaning pump. However, as described, this system would not be debited.

3.Q: What if you cannot be sure if other conditions may exist which could affect the above system?

A:Fix the submerged inlet.

4.Q: Can a check-valve be used in place of a vacuum breaker to prevent back siphonage in a water system?


5.Q: When a reinspection is requested because of low check-rating results, how soon after the due date must the paperwork reach Washington, D.C.?

A:Fifteen days is the general guideline.

6.Q: Are phosphatase tests required to be run on cultured products?


7.Q: Are antibiotic tests required to be run on cultured products?

A:Not at this time.

8.Q: Do we rate all products by a single-service container manufacturer or only those used for dairy products?

A: We are not required to evaluate the production of products except those which will be used for milk.

9.Q: Are 2400 units of Vitamin A actionable when 2000 is required?

A: It should be corrected but with such a small deviation voluntary correction should be used to achieve compliance.

10.Q: Where should Vitamins be added with respect to the separation of milk?

A: Vitamins which are soluble in milkfat should be added after separation. All vitamins must be added prior to pasteurization.

11.Q: Are there any high pressure pumps now on the market which do not require a low pressure cut out switch or other equivalent protection?

A: No. Not to our knowledge.

12.Q: DeLaval high pressure pumps are now being sold as needing no low pressure cut out switch or other protection because the pump will not pump without line pressure. Can we recognize this claim as accurate?

A: Not at this time. It has yet to be shown that while the pump is in operation, if the line pressure should drop the pump will stop pumping while there is still positive line pressure. If the pump does not stop until zero line pressure is reached, it does not meet the pubic health need for protection.


13.Q: Must an original rating of a newly constructed milk plant or dairy farm be debited if less than four samples are on record?

A: No. If plant has been in operation less than six months.

14.Q: What about an older plant or farm which has been functioning under a State permit previously but has recently come under the IMS program?

A: Yes. The four samples are required to receive the applicable sanitation and enforcement credit.

15.Q: Describe the possible approved ways to protect a single inlet pipe rinsing through nonpotable water in a stock trough.

A: The most common methods are:

  1. Double case the inlet pipe where it passes through the standing water and provide free drainage for any liquid accumulated between the pipes.
  2. Protect the remainder of the system by placing an approved backflow preventer on the line to the stock trough down stream from the last tee which goes to any potable water use.

16.Q: Must metal cans used for pasteurized cream come from an approved and listed single-service source?

A: Not if they are constructed of safe materials and sanitized prior to use.

17.Q: Are there any listed sources for metal cans?

A: No.

18.Q: Does this mean that at least for now, metal cans must be sanitized?

A: Yes.

19.Q: Must bag in box outlet valves and plastic materials used to line milk caps come from an approved source?

A: After further consideration, MSB has concluded that these sources should be approved and listed. It is not necessary for the component parts to be bacteriologically tested so long as they are included in the bacteriological test of the final assembled bag or cap.

20.Q: What standards are required to be met for the filter for the manhole of a tank truck during unloading in a covered but unenclosed area or the vent of a silo which is located in a raw milk receiving area?

A: While there is no specific standard, we normally accept filter media similar to that used to filter milk.

21.Q: What about steel wire?

A: No. It must be single service.

22.Q: What about a furnace filter?

A. No.

23.Q: What particle size are we worried about filtering out?

A: The PMO does not provide specifics, but the intent is to filter out dust and particulate matter which may be present in the air in a tank truck receiving bay.

24.Q: Does one end of a tubular precooler have to open into a milk house?

A: Yes. A milk house with sufficient space for disassembly, inspection and manual cleaning of the precooler when necessary.

25.Q: Is a screen door acceptable between a barn and a milk house?

A: No. A tight-fitting, self-closing, solid door is required.

26.Q: What about a compressor room with only a screen door or large screen between it and the milk house?

A: When only a screen door separates them, it is considered to be part of the milk house and would be evaluated as such.

27.Q: What about properly designed vents between a compressor room and a milk house?

A: These are considered to be an adequate separation.

28.Q: Is a water line hooked up directly to the lid of a vat pasteurizer debitable under the PMO if the water line is not equipped with a leak detector valve?

A: It is not debitable under Item 16p a(2)(h) (leak protector valves). It could be debitable under Item 15p, protection from contamination or Item 7p, water supply, if it is not properly installed and/or operated.

29.Q: What protection is required?

A: It should not be directly connected when product is in the vat. A swing elbow or other device to assure that any leakage past the last valve does not enter the vat and thereby adulterate the product. If a submerged inlet exists, it would also be an Item 3p violation, unless properly protected by an air break.

30.Q: May a State set standards in excess of those required by the PMO?

A: Yes.

31.Q: How do we pro-rate enforcement rating debits on sampling for either farms or plants?

A: IMS A-18 tells us what criteria to use, but the final decision as to how much emphasis to give each item is a matter of professional judgment.

32.Q: Is recirculated cooling water or glycol in the head of a blow mold machine required to be protected and tested?

A: Not unless the cooling water or glycol is also used in another application which does require protection.

33.Q: Is an air space heater required if the product temperature is 5x higher than the minimum pasteurization temperature?

A: This question reflects a common misconception. The actual requirement is that the air space above the product must be 5x higher than the minimum pasteurization temperature. This may or may not be accomplished if the product is heated 5x above the minimum.

34.Q: Can a directly plumbed sealed water tank with no vent be used as a separate system to provide the required protections for a high pressure pump?

A: No.

35.Q: What about if you add a vacuum breaker?

A: Not unless the vacuum breaker is spring loaded and will open to the air while there is still positive line pressure.

36.Q: Is the JMO strip chart acceptable for use as a recorder controller chart?

A: The strip chart reviewed is not satisfactory because it is not graduated in 1x graduations in the pasteurization range.

37.Q: There is an in-line ~mastitis indicator~ which consists primarily of a woven screen. Where do we mark the use of this device?

A: Under equipment construction. Item 9r.

38.Q: What is the status of Insecta-Paint (both pre-mixed and the insecticide which the farmer adds to his own paint)?

A: The material (Chlorpyrifos) which the farmer adds to his own paint is not approved by EPA for use on diary farms. The pre-mixed product has recently been approved by EPA after a change in labeling to be used in dairy farms and other farm buildings but may not be used in milk rooms, milk houses or other food producing areas.

39.Q: Is acid whey required to comply with the cooling and/or the double surge tank (emptied and cleaned every four hours) requirement of the DMO?

A: This requirement is intended to prevent the growth of staphylococcus organisms and the subsequent production of Staph. toxins. Staphylococcus will seldom produce toxin at a pH of 4.7 or less, although it may grow slowly. Therefore, acid whey with a pH of less than 4.7 is not required to meet these requirements.

40.Q: Are rubber collars on lines from precookers to farm bulk milk tanks acceptable in lieu of metal collars?

A: If they are made of approved materials and if they fit tightly enough around the cold pipe to prevent condensate from getting into the product.

41.Q: Is sodium nitrite permitted as an additive to cooling water to inhibit corrosion inside blow mold heads if the cooling water is used for other food cooling applications?

A: It would appear that its use in water to cool blow mold heads would not be a potential problem due to the thickness of the metal separating the water and the blow mold chamber. If the cooling water has additional plant applications such as milk t water under pressurized systems, there may be a potential for cross contamination. The CFR does not permit sodium nitrite as an additive to milk. If a dual use is desired, the manufacturer of this product should submit a question to FDA Center for Food Safety and Applied Nutrition.

Industry Session

1.Q: If sweet and acid whey are mixed and the pH stays in the acid whey range, can the product be handled as acid whey? (Be exempt from emptying the tanks every four hours when the product is in bacterial growth temperature ranges).

A: Yes, however, it would not meet the standards of identity and the names as specified in those standards may not apply.

2.Q: Must crystallized whey be cooled to 45x or less within 18 hours if not processed?

A: Yes.

3.Q: Newer separators operate at 140xF. The PMO says heat treated milk may not be heated above 125xF for separation, unless it is properly pasteurized. Is there any exception for these new separations?

A: No, unless they are incorporated as part of an HTST system and complete pasteurization of the whole milk and/or the cream and skim is accomplished as part of the system.

4.Q: May harmless lactic acid producing bacteria be added to raw milk to prevent the growth of psychrotrophic bacteria?

A: No.

5.Q: What is the status of the preincubated (PI) count?

A: The conference accepted the PI count as an alternative for the standard plate count. At this time, an implementation date has not been set.

NOTE: Since these questions were answered the NCIMS Executive Board has met and set an effective date of July 1, 1986, unless the 1985 conference elects to make changes. FDA is conducting a research project in conjunction with the STATES to compare the PI and SPC with actual sanitary conditions on the farm. This will be completed in late 1985. It is hoped that this study will provide additional data to reach a better decision on bacterial tests.

6.Q: Under what conditions can water taken from milk during reverse osmosis be used for general equipment washing or other plant purposes?

A: A procedure must be developed to assure safety. Data must be gathered to show that the procedure works. Protections under this procedure may be very similar to those already approved protection needed for water removed from milk in condensers.

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