Introduction to the essential concepts and processes involved in dairy plant technology, including milk reception, processing, packaging, and quality control.
Overview of Dairy Plant Technology
(A concise, structured guide for students, trainees, and plant personnel)
| Stage | Primary Objectives | Typical Unit Operations | Key Parameters |
|---|---|---|---|
| 2.1 Receiving & Pre‑conditioning | Accept raw milk, verify quality, adjust temperature | Milk reception tanks, flow meters, temperature sensors, pre‑coolers | Milk temperature (≤ 4 °C), flow rate, bacterial count, fat/protein content |
| 2.2 Standardization & Separation | Adjust fat/protein levels; separate cream | Separator (centrifuge), standardization valves, blending tanks | Fat % (e.g., 3.5 % for whole milk), skim/cream ratio |
| 2.3 Pasteurisation / Heat Treatment | Destroy pathogenic and spoilage microorganisms | Plate heat exchangers, tubular heat exchangers, HTST (High‑Temp/Short‑Time), UHT (Ultra‑High‑Temp) units | Temperature/time (e.g., 72 °C/15 s for HTST), Listeria/thermo‑tolerant bacteria log reduction |
| 2.4 Homogenisation | Reduce fat globule size → stable emulsion | High‑pressure homogenizer (15–25 MPa) | Particle size < 1 µm, pressure, temperature |
| 2.5 Cooling & Storage | Bring product to safe storage temperature | Plate coolers, glycol‑chilled water baths, insulated storage tanks | ≤ 4 °C, uniformity |
| 2.6 Fermentation / Culturing (optional) | Develop flavour, texture, functional properties | Fermenters, inoculation systems, temperature‑controlled vats | pH trajectory, incubation time (4–24 h), temperature (30–45 °C) |
| 2.7 Coagulation & Curd Handling (cheese) | Form curd, separate whey | Rennet addition, calcium chloride, cheese vats, curd cutters | pH (≈ 6.2 → 5.2), temperature (30–38 °C), coagulation time |
| 2.8 Aging / Ripening (cheese) | Develop flavor & texture | Ripening rooms, controlled humidity & temperature | 8–12 °C, 80–95 % RH, time (weeks–months) |
| 2.9 Packaging | Protect product, extend shelf‑life, provide information | Aseptic fillers, flow packers, vacuum packers, labeling stations | Fill volume, headspace, oxygen transmission rate |
| 2.10 Cleaning‑In‑Place (CIP) | Remove residues & microbes without disassembly | CIP loops, heat exchangers, pumps, chemical dosing (alkaline & acid) | Temperature (70–85 °C), flow rate, chemical concentration, contact time |
Heat Exchangers
Centrifuges / Separators