Troubleshoot on Milk & Cream
WHAT IS PASTEURIZATION?
It is the process of heating milk to high temperatures for a short time to kill harmful germs.
WHAT IS HOMOGENIZATION?
It is a mechanical process that forces milk through small holes to break up fat particles so they
do not float to the top as cream.
WHY DOES CREAM SEPARATE FROM MILK?
Cream contains mostly fat. Fat is lighter than water. In raw milk, fat globules
naturally rise to the surface over time.
WHAT IS THE DIFFERENCE BETWEEN MILK AND CREAM?
Milk is the whole liquid that comes from cows. Cream is the thick, high-fat part
of milk that is separated before processing.
WHAT CAUSES POWDER STICKINESS DURING SPRAY DRYING?
Stickiness happens when lactose exceeds its glass transition temperature and melts, causing powder to stick to dryer walls.
HOW DO YOU PREVENT EQUIPMENT BLOCKAGES FROM STICKINESS?
Producers use air-swept cooling, control dryer outlet temperatures, and manage the humidity of the hot air stream.
WHAT IS CAKING AND WHY DOES IT OCCUR?
Caking happens when powder absorbs moisture. This makes particles bond together to form hard, solid lumps instead of a free-flowing powder.
HOW DO YOU STOP CAKING IN STORED MILK POWDER?
Manufacturers pack powder in moisture-proof barriers (like nitrogen-flushed foil bags) and control warehouse humidity.
WHAT IS THE MAILLARD REACTION IN MILK POWDERS?
It is a chemical reaction between proteins and sugars. It causes unwanted brown colors, bitter flavors,
and loss of nutritional value during storage.
HOW CAN PRODUCERS MINIMIZE THE MAILLARD REACTION?
They lower the storage temperature, limit the powder's final moisture content, and use low-temperature preheating methods.
WHAT IS POOR SOLUBILITY IN MILK POWDER?
It means the powder fails to dissolve completely in water. It leaves behind visible, insoluble clumps, sediment, or a foamy layer.
WHAT CAUSES PROTEINS TO LOSE THEIR SOLUBILITY?
Excessive heat or incorrect pH levels during evaporation and drying cause protein denaturation, which permanently changes the protein's shape.
WHAT IS "INSTANTIZED" MILK POWDER?
Instantized powder is processed with lecithin to help it sink, disperse, and dissolve rapidly in cold water without lumping.
HOW DOES FAT AFFECT CREAM POWDER PRODUCTION?
Cream powders have high fat contents. This makes the powder heavier and highly prone to oxidizing and going rancid if exposed to oxygen.
WHAT IS OXIDATIVE RANCIDITY?
It is the degradation of fat. It produces an unpleasant "cardboard" or "metallic" smell and taste in high-fat powders.
HOW DO PRODUCERS PREVENT OXIDATIVE RANCIDITY?
They flush packaging with inert nitrogen gas (removing oxygen) and store the powder in dark, cool conditions.
WHAT IS HYDROLYTIC RANCIDITY?
It is the breakdown of fat into free fatty acids by the enzyme lipase. It causes a harsh, soapy flavor in the final product.
HOW IS LIPASE DEACTIVATED TO PREVENT HYDROLYTIC RANCIDITY?
Producers ensure that the raw milk is fully pasteurized at specific high temperatures to destroy these active enzymes.
WHAT ARE THE MAIN MICROBIAL HAZARDS IN DAIRY POWDER PRODUCTION?
The main threats are Salmonella, Cronobacter (especially in infant formulas), and
heat-resistant spore-forming bacteria.
HOW DO PROCESSING PLANTS CONTROL MICROBIAL CONTAMINATION?
They maintain strict pasteurization, microfiltration, plant sanitization, and hygienic dry-handling zones.
WHAT IS FOULING IN DAIRY EVAPORATION EQUIPMENT?
Fouling is the buildup of burned protein (Type A) and minerals (Type B) on the hot
surfaces of heaters and evaporators.
HOW DOES FOULING AFFECT THE PRODUCTION PROCESS?
Fouling slows down heat transfer, reduces operational efficiency, and requires frequent,
expensive equipment shutdowns for cleaning (CIP).
HOW DO SEASONAL AND DIETARY VARIATIONS IN RAW MILK IMPACT PRODUCTION?
HOW ARE DIFFERENT TYPES OF CREAM MADE?
Processors separate cream from milk at varying levels of fat. Heavy cream has
more fat than light cream. Sour cream is fermented using beneficial bacteria.
WHAT CAUSES MILK TO SPOIL?
Bacteria found in raw milk consume lactose (milk sugar) and turn it into lactic acid.
This causes the milk to sour and curdle.
HOW DO FARMERS STOP BACTERIA FROM GROWING ON THE FARM?
Farmers chill raw milk to 4° C right after milking. Cold temperatures slow down bacterial growth.
WHAT IS UHT MILK?
Ultra-High Temperature (UHT) milk is heated to extreme heat (≈ 140 °C) to kill all bacteria. It allows
the milk to sit on shelves without refrigeration for months.
WHAT IS RAW MILK?
It is milk that has not been pasteurized. Public health agencies warn against drinking it because
it can carry dangerous germs like E. coli and Salmonella.
WHAT ARE SOMATIC CELLS IN MILK?
They are mostly white blood cells. A high number of somatic cells usually means the
cow has a udder infection called mastitis.
HOW DO HIGH SOMATIC CELL COUNTS AFFECT PRODUCTION?
They change the chemistry of the milk. This lowers the quality of finished products and reduces cheese yield.
WHAT IS MASTITIS AND WHY IS IT A PROBLEM?
Mastitis is an infection in a cow's udder. It decreases milk production and lowers milk quality.
WHY DOES MILK SOMETIMES TASTE BITTER OR METALLIC?
This can happen if the milk is not cooled fast enough or if the enzymes in the milk break down fat incorrectly.
14. What is the shelf life of fresh pasteurized milk?
If it is kept constantly cold (≤ 4° C), fresh milk usually stays good for 7 to 14 days. [1]
If it is kept constantly cold (≤ 4° C), fresh milk usually stays good for 7 to 14 days. [1]
15. Can you freeze milk and cream?
Yes. However, freezing changes the texture of milk and thins out cream. It may separate when thawed. [1]
Yes. However, freezing changes the texture of milk and thins out cream. It may separate when thawed. [1]
16. How is butter made from cream?
Butter is made by continuously shaking (churning) cream until the fat clumps together, separating from the liquid buttermilk
Butter is made by continuously shaking (churning) cream until the fat clumps together, separating from the liquid buttermilk
