Abattoir Practices and Animal Products Technology

BOILING AND DRAINING

Boiling

• The purposes of boiling are
  • Sterilization of the material, making it safe for use as stock feed.
  • Partial removal of the moisture which is squeezed but during shrinkage and
  • Separation of fat
• Fat is removed for two main reasons such as
• Economic
  • Sold for industrial purposes (for soap-making or tannery use) and fat realizes a higher price than stock feed.
  • As stock feed, sold on a protein basis, payment is made for proteins only and not for fat or moisture (moisture should not exceed 5 to 6%).
• Keeping quality
  • Fat causes rancidity thus rendering the product unpalatable, unsound and therefore unsaleable.
• Boiling may be done in any kettle or oil or petrol drum on an open fire, as there is no danger of burning.
• Before boiling starts, the meat is cut or mixed prior to rendering.
• Wherever possible, the meat should be minced or at least chopped.
• Bones should be boiled together with the meat to recover the fat and loose tendons, cartilages or meat.
• First, water at the rate of twice the amount of material to be cooked is added and brought to boil and then the offal are to be added.
• The meat is quickly removed from water leaving fat and water in the drum. The fat is then drained off for refining.

Draining

• To remove further moisture, mass is drained the in a basket for 10 to 20 minutes.