Dairy Establishment Inspection Manual – Chapter 19 Appendices
Appendix 1 Culinary Steam

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"Culinary steam" refers to steam used in direct contact with milk and dairy products.

The following dairy plant uses are examples of processes requiring culinary type steam:

  1. Steam injection into product hot wells for production of evaporated milk, sweetened condensed milk, dry milk powders, etc.
  2. Making ricotta or cottage type cheeses with direct steam injection.
  3. Steam injection into the heating chamber of "vacreator" or similar continuous pasteurizing or sterilizing equipment.
  4. For direct heating of cheese in a process cheese cooker.
  5. For direct injection heating of water to be recirculated in a continuous type mozzarella curd mixer.
  6. For direct injection heating of water to be added to melted butter in melting vats or at the separator during the manufacture of butter oil.
  7. Any similar heating application where appreciable amounts of steam contact the product.

The following methods and procedures will provide steam of culinary quality for use in the processing of milk and milk products.

Source of Boiler Feed Water

Potable water or water supplies, acceptable to the regulatory agency, will be used.

Feed Water Treatment

Feed waters may be treated, if necessary, for proper boiler care and operation. Boiler feed water treatment and control shall be under supervision of trained personnel or a firm specializing in industrial water conditioning. Such personnel shall be informed that the steam is to be used for culinary purposes. Pretreatment of feed waters for boilers or steam generating systems to reduce water hardness, before entering the boiler or steam generator by ion exchange or other acceptable procedures, is preferable to the addition of conditioning compounds to boiler waters. Only compounds complying with regulations may be used to prevent corrosion and scale in boilers, or to facilitate sludge removal.

Greater amounts shall not be used of the boiler water treatment compounds than the minimum necessary for controlling boiler scale or other boiler water treatment purposes. No greater amount of steam shall be used for the treatment and/or pasteurization of milk and milk products than necessary.

It should be noted that tannin, which is also frequently added to boiler water to facilitate sludge removal during boiler blowdown, has been reported to give rise to odour problems. and should be used with caution.

Boiler compounds containing cyclohexylamine, morpholine, octadecylamine, diethylaminoethanol, trisodium nitrilotriacetate, and hydrazine are not be permitted for use in steam in contact with milk and milk products.

Boiler Operation

A supply of clean, dry saturated steam is necessary for proper equipment operation. Boilers and steam generation equipment shall be operated in such a manner as to prevent foaming, priming, carryover and excessive entrainment of boiler water into the steam. Carryover of boiler water additives can result in the production of milk off-flavours. Manufacturer's instructions regarding recommended water level and blow-down should be consulted and rigorously followed. The blow-down of the boiler should be carefully watched, so that an over-concentration of the boiler solids and foaming is avoided. It is recommended that periodic analysis be made to condensate samples. Such samples should be taken from the line between the final steam separating equipment and the point of the introduction of steam into the product.

Piping Assemblies

See illustrations on page 27 - App. 1-3 for suggested piping assemblies for steam infusion or injection. Other assemblies which will assure a clean, dry saturated steam are acceptable.

Note: For additional details, see 3 A Accepted Practices for a Method of Producing Steam of Culinary Quality, Number 609-01.

Click on image for larger view
Image - Culinary Steam Piping Assembly for Steam Infusion or Injection. Description follows.

Description of image - Culinary Steam Piping Assembly for Steam Infusion or Injection

This image shows the Culinary Steam Piping Assembly for Steam Infusion or Injection.

The parts consist of:

  1. Stop Valve off Steam Main
  2. Filter, Adams Carbon Core or Equivalent
  3. Condensate Trap
  4. Pressure Gauge
  5. Steam Pressure Regulating (Reducing) Valve
  6. Steam Throttling Valve (automatic or manual). An Alternate location is shown at B.
  7. Steam Purifier, Anderson Hi-eF or equivalent
  8. Steam Sampling Valve and Connection
  9. Spring Loaded Sanitary Check Valve.

A - Desuperheater or sufficient length of piping to desuperheat steam shall be incorporated between the pressure regulating (reducing) valve and the steam purifier.

B - Acceptable alternate location for steam throttling valve.

C - Sanitary tubing and fittings shall be used between the point indicated and the processing equipment.

Note: Additional valves, strainers, traps, gauges and piping may be used for control and convenience in operation. The location of the steam throttling valve is not restricted to the positions indicated on the drawing. The positions of items 2 and 7 may be reversed if desired.

Click on image for larger view
Image - Culinary Steam Piping Assembly for Airspace Heating or Defoaming. Description follows.

Description of image - Culinary Steam Piping Assembly for Airspace Heating or Defoaming

This image shows the Culinary Steam Piping Assembly for Airspace Heating or Defoaming.

The parts consist of:

  • Steam supply pipe with a steam strainer
  • 0 - 100 pounds Steam trap of not less than 3' in length and ¾" in diameter
  • Condensation Leg of not less than 3' in length of ¼" pipe with a ¼" control needle valve and a 0-30 pounds Steam Gage
  • Auxiliary Water Trap of not less than 12" in length from the clean orifice above the remove pipe and not less than 1 ½" in diameter with a ⅛" drain hole
  • Final section to the processing equipment made up of sanitary tubing and fittings

References

  • Grade "A" Pasteurized Milk Ordinance 1993
  • U.S. Department of Health and Human Services
  • Public Health Service, Food and Drug Administration
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