Classification of sterilization methods and structures of sterilizers.

**Types of Retorts and Their Features**

1. **Control Methods:**

- **Manual Retort:** All valves and pumps are manually operated, including water addition, temperature increase, holding, and reduction.

- **Electrically Controlled Semi-Automatic Retort:** Pressure is managed by an electric contact pressure gauge, and temperature is controlled by a sensor (±1°C accuracy). Temperature reduction is manual.

- **Computerized Semi-Automatic Retort:** A PLC and text display process sensor signals, storing sterilization data. Temperature control accuracy is ±1°C.

- **Fully Automatic Sterilizer Control:** Operated via PLC and touch screen, this system stores sterilization processes, sounds an alarm upon completion, and offers ±0.5°C temperature control accuracy.

2. **Sterilization Methods:**

- **Water Bath Sterilizer:** Food is immersed in hot water for uniform heat distribution.

- **Steam Sterilizer:** Steam is directly injected into the pot, but air presence may cause uneven heat distribution.

- **Spray Retort:** Hot water is sprayed through nozzles for uniform temperature, quick heating, and cooling, ideal for soft-packaged foods.

3. **Retort Structure Types:**

- Single-tank, double-layer, parallel double-tank, vertical, electric/steam dual-purpose, and rotary retorts.

4. **Retort Materials:**

- All-stainless steel, semi-steel, and carbon steel options.