Milk processing methods center on preservation, safety, and quality improvement. The main steps cover pretreatment, sterilization, homogenization, packaging, and further processing. Each step affects shelf life, texture, and nutritional retention. Hansheng Automation can machine replacement parts for milk processing equipment, including pump components, homogenizer valves, and filling machine parts, to customer drawings.
Pretreatment
Clarification
Clarification removes impurities, somatic cells, and other foreign matter from raw milk. Filtration catches larger debris, while centrifugal clarifiers separate fine particles and cells. Clean raw milk supports consistent downstream processing and protects equipment from buildup.
Rapid Cooling
Raw milk is cooled to 0 to 4 C to suppress microbial growth. The faster the milk reaches this range after collection, the better the raw milk quality. Holding tanks maintain the temperature until the next process step.
Standardization
Standardization adjusts the fat and protein ratio to match the target product. Whole milk, low-fat milk, and skim milk each have different requirements. The standardization step determines the composition of the final product and affects texture and mouthfeel.
Sterilization
Pasteurization
Pasteurization kills pathogenic bacteria while retaining some active nutrients. It comes in two forms. Low-temperature long-time (LTLT) holds milk at 62 to 65 C for 30 minutes. High-temperature short-time (HTST) holds milk at 72 to 75 C for 15 seconds. Pasteurized milk requires cold chain storage and has a short shelf life.
Ultra-High-Temperature (UHT) Treatment
UHT treatment holds milk at 135 to 140 C for 2 to 6 seconds. It kills all microorganisms and spores. Combined with aseptic packaging, UHT milk can be stored at room temperature for months. The choice between pasteurization and UHT depends on the target market and distribution conditions.
Homogenization
How It Works
High-pressure homogenizers break fat globules in milk into smaller sizes. This prevents fat from rising and separating during storage. It also improves mouthfeel and product stability. Homogenization pressure is typically set according to the fat content and the desired texture.
Effect on Product Quality
Homogenized milk has a smoother texture and a more uniform appearance. It also reduces the risk of cream layer formation in the package. For yogurt and other fermented products, homogenization before fermentation affects curd structure and whey separation.
Packaging
Cold Chain Packaging
Pasteurized milk uses glass bottles, pasteurized plastic bags, or gable-top cartons. These packages are designed for cold chain distribution. They protect the product during short-term storage and transport.
Aseptic Packaging
UHT milk uses aseptic composite packaging such as Tetra Brik or Tetra Fino. The package and filling process keep the product sterile after treatment. Aseptic packaging is what allows UHT milk to be stored without refrigeration.
Further Processing Techniques
Spray Drying
Spray drying turns concentrated milk into powder. The concentrate is atomized into fine droplets and dried in hot air. The result is milk powder with a long shelf life and stable quality.
Lactic Acid Fermentation
Lactic acid fermentation produces yogurt. Starter cultures convert lactose into lactic acid, which thickens the milk and creates the characteristic tang. Temperature and fermentation time control the final texture and flavor.
Coagulation and Fermentation
Coagulation fermentation produces cheese and butter. Rennet or acid causes milk proteins to coagulate, and the curd is cut, cooked, pressed, and salted. Butter production separates cream and works it into a solid mass.
Nutrient Fortification
Nutrient fortification adds vitamins, minerals, or other nutrients to produce fortified milk. The added ingredients are blended into the milk under controlled conditions to ensure even distribution.
Safety Notes
Operating high-temperature sterilizers and high-pressure homogenizers requires strict adherence to procedures. Burn risk from hot surfaces and pipes is real. High-pressure lines can cause mechanical injury if fittings fail. Regular inspection of seals, valves, and pressure relief devices is part of safe operation. When replacement parts are needed, we can machine them to drawing to keep equipment running safely.
Our precision custom machining capability is not limited to milk processing equipment. Hansheng Automation also produces parts for food processing equipment, filling machinery, and printing machinery, along with precision components for yachts and RC cars. From single parts to small batch runs, we machine to customer drawings and deliver parts for assembly.
