How to Operate the Small Yogurt Production Line: Complete Step-by-Step Guide

Before operating a small yogurt production line, make sure you are familiar with and understand the equipment's operating manual and safety procedures. This comprehensive step-by-step guide covers the complete operation process, from raw milk reception to finished product packaging, with detailed parameters and safety precautions.

Basic Process of the Small Yogurt Production Line

The basic production process of yogurt follows this sequence:

Raw Milk Storage → Filtration → Preheating → Homogenization → Pasteurization → Cooling → Inoculation → Fermentation → Filling → Cold Storage

Each stage requires specific temperature control, timing, and equipment operation to ensure consistent product quality.

Small Yogurt Production Line Equipment List

A complete small yogurt production line (200-500L daily capacity) includes the following equipment:

Equipment	Function	Capacity	Key Parameters
Raw Milk Cooling Tank	Storage and cooling	200-500L	Maintain 4°C
Single/Duplex Filter	Remove impurities	100 mesh	Flow rate: 500-1000L/hr
Milk Pump	Transfer milk between stages	1-3 m³/hr	Food-grade stainless steel
Preheating Tank	Warm milk to processing temp	200-500L	40-50°C, 20 min
Homogenizer	Break down fat globules	300L/hr	150-250 bar, 60-70°C
Pasteurization Tank	Heat treatment for safety	200-500L	85°C, 30 min
Fermentation Tank	Culture incubation	200-500L	42°C, 6-8 hours
Filling Machine	Package yogurt	500-1000 cups/hr	Automatic or semi-auto
CIP Cleaning System	Automated cleaning	Match line	80-90°C, chemical dosing

Step-by-Step Yogurt Processing Operation

Step 1: Raw Milk Reception and Storage

Objective: Receive and store fresh milk at proper temperature

Operation Procedure:

1. Quality Testing: Test incoming milk for temperature (<10°C), acidity (pH 6.6-6.8), and antibiotic residues
2. Transfer to Tank: Use stainless steel milk pump to transfer raw milk to cooling tank
3. Cool to 4°C: Activate cooling system to maintain milk at 4°C until processing
4. Record Data: Log milk volume, temperature, supplier, and test results

Key Parameters:

Parameter	Standard	Action if Out of Range
Temperature	<10°C on arrival	Reject if >10°C
Storage Temperature	4°C	Adjust cooling system
pH	6.6-6.8	Test for spoilage
Antibiotic Test	Negative	Reject milk if positive

Step 2: Filtration

Objective: Remove impurities and foreign materials from raw milk

Operation Procedure:

1. Prepare Filter: Install clean 100-mesh filter element
2. Start Pump: Turn on milk pump at low speed
3. Monitor Flow: Ensure steady flow through filter
4. Check Filter: Inspect filter element after each batch
5. Clean/Replace: Clean or replace filter if clogged

Key Parameters:

Parameter	Standard
Filter Mesh Size	100 mesh (150 μm)
Flow Rate	500-1000L/hr
Filter Cleaning	After each batch
Filter Replacement	Weekly or when damaged

Step 3: Preheating

Objective: Warm milk to optimal temperature for homogenization

Operation Procedure:

1. Transfer Milk: Pump filtered milk to preheating tank
2. Set Temperature: Adjust heating system to 40-50°C
3. Hold Time: Maintain temperature for 20 minutes
4. Monitor: Check temperature every 5 minutes
5. Prepare for Next Stage: Ensure homogenizer is ready

Key Parameters:

Parameter	Standard	Notes
Temperature	40-50°C	Optimal for homogenization
Holding Time	20 min	Ensure even heating
Agitation	Continuous	Prevent hot spots

Step 4: Homogenization

Objective: Break down fat globules for smooth, uniform texture

Operation Procedure:

1. Preheat Homogenizer: Ensure milk temperature is 60-70°C
2. Set Pressure: Adjust homogenization pressure to 150-250 bar
3. Start Machine: Turn on homogenizer at low speed
4. Monitor: Check pressure gauge and milk temperature
5. Process Batch: Run entire batch through homogenizer (approximately 1 hour for 300L)
6. Clean: Flush system with warm water after use

Key Parameters:

Parameter	Standard	Impact
Temperature	60-70°C	Lower temp reduces efficiency
Pressure	150-250 bar	Higher pressure = finer texture
Processing Time	~1 hour for 300L	Depends on capacity

Step 5: Pasteurization (Sterilization)

Objective: Eliminate pathogenic bacteria while preserving beneficial properties

Operation Procedure:

1. Transfer Milk: Pump homogenized milk to pasteurization tank
2. Heat to 85°C: Activate heating system (350# heat-conducting oil or hot water)
3. Hold Temperature: Maintain 85°C for 30 minutes
4. Monitor: Check temperature every 5 minutes
5. Record: Log time, temperature, and batch number
6. Prepare for Cooling: Ensure cooling system is ready

Key Parameters:

Parameter	Standard	Notes
Temperature	85°C	Standard pasteurization
Holding Time	30 min	For 300L batch
Large Batch (>300L)	40-60 min	Adjust time accordingly
Heat Source	Hot water or thermal oil	Depends on equipment

Step 6: Cooling and Inoculation

Objective: Cool milk to fermentation temperature and add starter culture

Operation Procedure:

1. Activate Cooling: Use cold water for pre-cooling (0.3-0.5 hours)
2. Cool to 45°C: Monitor temperature until it reaches 42-45°C
3. Prepare Culture: Measure starter culture (2-3% of milk volume)
4. Add Culture: Sprinkle culture evenly over milk surface
5. Gentle Mixing: Agitate slowly for 5-10 minutes to distribute culture
6. Seal Tank: Close fermentation tank to prevent contamination

Key Parameters:

Parameter	Standard	Notes
Cooling Time	0.3-0.5 hours	Use cold water
Target Temperature	42-45°C	Optimal for culture
Culture Dosage	2-3% of milk volume	Follow manufacturer instructions
Mixing Time	5-10 min	Gentle agitation

Step 7: Fermentation

Objective: Allow culture to convert lactose to lactic acid

Operation Procedure:

1. Set Temperature: Maintain fermentation tank at 42°C
2. Monitor pH: Check pH every hour (target: 4.5-4.6)
3. Check Consistency: Observe yogurt texture after 4 hours
4. End Fermentation: Stop when pH reaches 4.5-4.6 (typically 6-8 hours)
5. Cool Immediately: Reduce temperature to 4-6°C to stop fermentation
6. Transfer to Filling: Move fermented yogurt to filling machine

Key Parameters:

Parameter	Standard	Notes
Temperature	42°C	Maintain ±0.5°C
Fermentation Time	6-8 hours	Depends on culture activity
Target pH	4.5-4.6	Stop fermentation at this point
Cooling Temperature	4-6°C	Prevent over-fermentation

Step 8: Filling and Packaging

Objective: Package yogurt into containers for distribution

Operation Procedure:

1. Prepare Filling Machine: Clean and sanitize all contact surfaces
2. Set Fill Volume: Adjust filling machine to target volume (e.g., 200g per cup)
3. Load Containers: Place empty cups/bottles on conveyor
4. Start Filling: Activate filling machine
5. Seal: Apply lids or foil seals immediately after filling
6. Label: Apply product labels with date and batch number
7. Cold Storage: Transfer filled products to cold room (2-6°C)

Key Parameters:

Parameter	Standard	Notes
Fill Volume	Per product spec	±2% accuracy
Filling Temperature	4-6°C	Maintain cold chain
Sealing Temperature	150-180°C	For heat sealing
Storage Temperature	2-6°C	Until distribution

Safety Precautions

Personal Safety

Precaution	Requirement
Protective Clothing	Wear clean uniform, hairnet, gloves
Hand Washing	Wash hands before handling equipment
Footwear	Use sanitized, non-slip footwear
Health Check	No open wounds or illness

Equipment Safety

Precaution	Requirement
Lockout/Tagout	Disconnect power before maintenance
Hot Surfaces	Allow equipment to cool before handling
Chemical Handling	Wear gloves when handling cleaning chemicals
Electrical Safety	Keep water away from electrical panels

Food Safety

Precaution	Requirement
Temperature Control	Monitor and record all temperatures
Cleaning Schedule	Follow CIP protocol after each batch
Cross-Contamination	Separate raw and processed areas
Record Keeping	Document all production parameters

Daily Operation Checklist

Task	Frequency	Time
Equipment inspection	Before start	15 min
CIP cleaning	After each batch	30-60 min
Temperature verification	Every 2 hours	5 min
pH testing	During fermentation	Every hour
Quality check	After filling	10 min
End-of-day cleaning	End of shift	60 min

Conclusion

Operating a small yogurt production line requires attention to detail, proper temperature control, and strict hygiene practices. By following this step-by-step guide, you can consistently produce high-quality yogurt while maintaining food safety standards. Regular training, documentation, and preventive maintenance are key to long-term operational success.

Contact Shuliy Machinery for comprehensive operator training programs and technical support for your yogurt production line.