Review Flashcards on Milk and Dairy Product Processing

Flashcards covering key vocabulary related to milk preservation, pasteurization, cheese and yogurt production, packaging, and UHT processing.

Main aim of milk processing

Destroys harmful microorganisms to make milk safe for consumption and extends shelf life.

Thermisation

Heating milk at 57–68°C for 30 minutes to extend shelf life before further processing.

Clarification

Removes dirt and foreign substances from milk using a rotating clarifier.

Pasteurization

Microbicidal heat treatment that reduces pathogenic microorganisms to a safe level.

UHT (Ultra High Temperature)

Heating milk to 135–150°C for 2–10 seconds to extend shelf life and ensure microbial safety.

Sterilization

Applying high heat to milk in sealed containers to make it commercially sterile for long-term storage.

Homogenization

Applied to pasteurized milk to reduce fat globule size, preventing cream separation.

Pasteurization (definition)

Microbicidal heat treatment aimed at reducing pathogenic microorganisms in milk to safe levels.

Holder Method

Heats milk to 63°C for 30 minutes, then cools it to 4°C immediately.

Alternative Pasteurization Method

Heats milk to 72°C for 15 seconds, then cools it to 4°C immediately.

High Temperature Short Time (HTST)

Common form of pasteurization that heats milk to 161°F (71.8°C) for 15 seconds or 145°F (63°C) for 30 minutes.

Ultra High Temperature (UHT) Pasteurization

Heating milk to 135°C–150°C for 2–10 seconds.

Alkaline Phosphatase Test

Used to confirm adequate pasteurization by testing for an enzyme more heat-resistant than most non-spore-forming pathogens.

Milk Standardization (Cheese)

Adjusting the fat-to-casein ratio of milk to ensure uniform cheese quality.

Acidification/Souring (Cheese)

Adding starter cultures (mainly Lactobacillus spp.) to reduce pH and aid coagulation in cheese making.

Coagulation/Curdling (Cheese)

Adding coagulating agents like rennet or acids to form curds in cheese making.

Cutting the Curd (Cheese)

Cutting the curd to release whey in cheese making; affects cheese texture.

Cooking/Scalding (Cheese)

Gently cooking the curd to encourage whey expulsion and further acid development in cheese making.

Salting (Cheese)

Adding salt to enhance flavor, inhibit spoilage organisms, and promote syneresis in cheese making.

Pressing (Cheese)

Pressing the curds to remove excess whey and form solid blocks in cheese making.

Ripening/Maturation (Cheese)

Aging cheese under controlled humidity and temperature to develop flavor, texture, and aroma.

Milk Standardization (Yogurt)

Adjusting milk solids and fat content, and increasing protein using milk powder for yogurt production.

Set Yogurt

Fermented in the final container, resulting in a firm texture.

Stirred Yogurt

Fermented in bulk, then stirred and packaged.

Drinking Yogurt

Similar to stirred yogurt, but more agitated.

Frozen Yogurt

Prepared like ice cream with higher solids content.

Concentrated Yogurt

Water removed using heat and vacuum to concentrate the yogurt.

Role of Refrigeration in Milk Quality

Slows down the growth of spoilage microorganisms and prevents multiplication of pathogens.

Polyethylene (PE)

Commonly used for plastic milk pouches; protects from moisture and contamination.

High-density polyethylene (HDPE)

Used for milk bottles; strong, durable, and opaque to light.

Glass Bottles

Reusable, non-reactive, and preserve taste but are heavy and breakable.

Paperboard with plastic/foil lining

Provides strength and moisture barrier; used in cartons.

Polystyrene Cups

Used for fermented products like yogurt; rigid and easy to print on.

PET (Polyethylene terephthalate) Bottles

Transparent and recyclable; used for flavored milk.

Vacuum-sealed Packs

Used for cheese and butter; minimize air exposure and spoilage.

Pasteurization Effect

Reduces microbial load but does not kill all microorganisms; requires refrigeration.

UHT Sterilization Effect

Destroys both pathogens and heat-resistant spores, making it sterile; longer shelf life at room temperature if aseptically packaged.

FSSAI Definition of UHT

Heating to ≥135°C for ≥1 second followed by aseptic packaging for room temperature storage of at least 15 days.