Milk Testing
An e-Manual by Manoj Kumar
Assistant Professor
Bundelkhand University, Jhansi, UP, INDIA
Table of Contents
1. Introduction to Milk Testing. 1
1.1 Importance of Milk Testing. 1
1.2 Objectives of Milk Quality Control 5
1.3 Classification of Milk Tests 7
1.4 Sampling Techniques and Precautions 12
2. Physical Testing of Milk. 17
2.1 Organoleptic Evaluation. 17
2.2 Temperature Measurement 22
2.3 Sedimentation Test 26
2.4 Clot-on-Boiling (COB) Tests 27
2.5 Specific Gravity (Lactometer Test) 28
2.6 Freezing Point Determination. 31
3. Chemical Testing of Milk. 33
3.1 Determination of Fat Content 33
3.2 SNF (Solids-Not-Fat) and Total Solids 36
3.3 Protein and Casein Estimation. 38
3.3 Protein and Casein Estimation. 40
3.5 Acidity and pH. 41
3.6 Detection of Neutralizers, Preservatives, and Adulterants 42
4. Microbiological Testing. 49
4.1 Standard Plate Count (SPC) 49
4.2 Methylene Blue Reduction Test 51
4.3 Resazurin Test 52
4.4 Coliform Count 54
4.5 Somatic Cell Count 56
4.6 Pathogen Detection (e.g., E. coli, Listeria, Salmonella) 58
5. Adulteration and Contamination Detection. 60
5.1 Common Adulterants in Milk. 60
5.2 Qualitative Tests for Adulterants 62
5.3 Quantitative Estimation. 65
5.4 Rapid Test Kits and Strip Tests 71
5.5 Legal and Safety Aspects 74
6. Instrumental Methods in Milk Testing. 81
6.1 Milko-Tester and Lactoscan. 82
6.2 Infrared Spectroscopy. 84
6.3 Ultrasonic Milk Analysers 88
6.4 pH Meter, Conductivity Meter 91
6.5 Automatic Milk Collection Unit (AMCU) Testing Systems 94
7. Quality Standards and Regulatory Requirements 96
7.1 BIS and FSSAI Standards 96
7.2 Codex Alimentarius Guidelines 100
7.3 International Standards (ISO) 104
7.4 Legal Metrology in Milk Measurement 108
7.5 Lab Accreditation and Good Laboratory Practices (GLP) 110
8. Sample Collection and Laboratory Practices 113
8.1 Types of Samples 113
8.2 Sample Preservation and Transport 117
8.3 Cleaning and Sterilization of Glassware. 119
8.4 Safety and Hygiene in Milk Labs 121
9. Milk Testing in the Supply Chain. 123
9.1 At the Producer Level 123
9.2 Milk Collection Centres 125
9.3 Dairy Plant Quality Control 127
9.4 Milk Testing for Export 129
10. Recent Advances and Digital Tools 131
10.1 Mobile Milk Testing Units 131
10.2 IoT and Sensor Technologies 133
10.3 Data Management and Cloud Integration. 135
10.4 AI/ML in Milk Quality Prediction. 137
Annexures 138
A1: Standard Operating Procedures (SOPs) 139
A2: Format for Milk Testing Reports 140
A3: Troubleshooting Common Test Errors 140
A4: Glossary of Terms 141
A5: Reference Values and Conversion Tables 141
References 142
Introduction to Milk Testing. 142