RENDERING FACILITIES

RENDERING FACILITIES

1. Poultry Rendering Process

In rendering plants, the goal is to convert poultry slaughter by-products (skin, fatty parts, internal organs, slaughter waste, etc.) into oil (poultry oil) and protein meal (poultry meal).

Stages:

1. Collection and Pre-Processing

• By-products from slaughterhouses are transported to the plant with refrigerated vehicles.
• Large pieces are reduced in size with a shredder/grinder.
• Foreign materials such as metal are removed with magnets.

2. Cooking / Sterilization

• The material is placed into a rendering cooker or continuous cooker.
• Cooked at 115–145 °C with steam injection for 40–90 minutes.
• Purpose: Denature proteins, eliminate microbes, and release fat.

3. Pressing

• The cooked mass is passed through a screw press.
• Solid and liquid phases are separated:
• Liquid phase → fat + water
• Solid phase → protein + bone fragments (raw poultry meal)

4. Fat Separation

• The liquid phase is sent to a decanter centrifuge or disk stack centrifuge.
• Poultry oil is separated from water and sludge.
• The oil can be used for biodiesel, feed additives, or technical oil.

5. Drying

• The solid phase (protein-rich part) is dried in a rotary dryer or disk dryer.
• Moisture is reduced to 8–10%.

6. Grinding and Packaging

• The dried mass is ground with a hammer mill to obtain poultry meal.
• Used as a protein source in animal feed or pet food.

2. Poultry Bone Processing

Bone processing is carried out for two different purposes:

• Feed industry → Meat & bone meal
• Food/cosmetics/pharmaceuticals → Gelatin, collagen

A. Meat & Bone Meal Production
1. Bone Collection and Grinding

• Slaughterhouse bones are collected and broken into smaller pieces with a crusher or bone grinder.

2. Cooking / Rendering

• The same rendering process is applied (115–145 °C, pressurized cooking).

3. Fat and Protein Separation

• Fat is separated from bones with screw press + centrifuge.
• Remaining: protein + minerals (Ca, P).

4. Drying and Grinding

• Moisture is reduced in dryers.
• Ground into meat & bone meal.

Use: Calcium-phosphorus source in poultry, fish, and livestock feed

B. Gelatin / Collagen Production

(From poultry skin, bone, and cartilage)
1. Pre-Processing

• Bones are washed and defatted.
• Demineralization: Calcium is removed with acid or alkaline baths.

2. Extraction

• Bones/cartilage are processed at low temperatures (50–70 °C) with hot water or enzymes.
• Collagen structures are released and dissolved in solution.

3. Filtration and Concentration

• Gelatin/collagen is filtered from the solution.
• Concentrated by evaporation.

4. Drying and Powdering

• Dried with a spray dryer.
• Powder gelatin or collagen is obtained.

Use: Food (desserts, capsules), pharmaceuticals, cosmetics

Critical Technical Parameters

• Temperature: 115–145 °C (for sterilization and fat separation)
• Pressure: 2–4 bar (in rendering cooker)
• Moisture: Final products must have 8–10% (otherwise spoilage occurs)
• Hygiene: To prevent cross-contamination, bone processing and rendering lines may be kept separate.