What is pasteurization?

The discovery (1864)

French chemist + microbiologist Louis Pasteur discovered that heating wine to specific temperatures (50-60°C / 122-140°F) for short periods killed the microorganisms causing it to spoil — without significantly changing taste or quality. Originally applied to wine + beer to prevent souring; later extended to milk + other foods.

Distinct from sterilization (kills ALL microorganisms including beneficial ones) — pasteurization kills pathogens + reduces spoilage organisms while leaving "beneficial" microbes potentially intact at lower levels.

The two standard methods

All achieve the same safety result via different time-temperature combinations.

What pasteurization kills

Pathogenic bacteria: - *Salmonella* — food poisoning bacterium - *E. coli* — including O157:H7 dangerous strain - *Listeria monocytogenes* — especially dangerous for pregnant women, immunocompromised - *Campylobacter* — leading cause of diarrhea - *Yersinia enterocolitica* - *Mycobacterium bovis* — historical milk-borne tuberculosis (rare now) - *Brucella* — milk-borne brucellosis (rare now)

Spoilage microorganisms: - Many yeasts + molds (extends shelf life) - Spore-forming bacteria are NOT killed — that's why pasteurized milk still spoils eventually

Foods commonly pasteurized

Raw vs pasteurized debate

Raw milk + raw cheese have nutritional + flavor advocates BUT: - Public health agencies (CDC, FDA, USDA, EFSA) recommend AGAINST raw milk for general population - Pregnant women, children, elderly, immunocompromised should NOT consume raw products - Raw cheese is legal but requires 60+ day aging in US for sale - Premium raw-milk advocates claim: better flavor, easier digestion (probiotic content), nutritional preservation - Public-health concern: Listeria, Salmonella, E. coli outbreaks documented

Pasteurization vs sterilization

• Pasteurization: heats just enough to kill pathogens; preserves most flavor + texture. Some bacteria + spores survive.
• Sterilization: kills ALL microorganisms via heat (commercial sterilization at 250°F+ for 15+ min) or other methods. Used for canned foods, medical equipment.
• UHT (Ultra-High-Temperature): closer to sterilization. Milk in tetra-pak cartons. Shelf-stable without refrigeration until opened.

Pasteurization in cooking + brewing

Eggs: pasteurized shell eggs available; allow safe use in raw-egg recipes (Caesar dressing, hollandaise, ice cream).

Sous vide poultry: long enough at lower temp = pasteurized. USDA chart shows 5+ minutes at 140°F = pasteurized chicken. Why sous vide chicken at 140°F is safer + juicier than 165°F roasted.

Beer brewing: traditional beers are unpasteurized + rely on alcohol + hops antimicrobial action. Modern commercial beers often pasteurized post-bottling.

Wine: most premium wine is NOT pasteurized — flavor compounds are more delicate; pasteurization can dull complex aging characteristics. Mass-market wines may be flash-pasteurized.

Pasteurization equivalency (sous vide chart)

For cooking poultry at lower temperatures, USDA accepts time-temperature equivalency:

This is why sous vide chicken at 145°F for 1.5 hours is just as safe as 165°F instantly.

Cross-reference: see /pages/what-temperature-for/chicken-thigh-internal-temp + /pages/what-temperature-for/ground-beef-internal-temp + /pages/what-temperature-for/pork-loin-internal-temp + /pages/what-temperature-for/sous-vide-chicken-breast + /pages/how-long-does/yogurt-ferment.