Food Preservation

Section 1Why food spoils

Food spoils when microbes grow, enzymes keep changing the food, or pests contaminate it. Bacteria, moulds, and yeasts grow best when they have food, moisture, warmth, and time. Here's the trick: preservation works by removing or controlling one or more of those conditions.

Section 2Temperature control

Chilling slows microbial growth, while freezing slows it even more by making water unavailable as ice. Heat methods, such as pasteurising and canning, kill many microbes. Watch out: freezing does not kill all microbes, so thawed food must still be handled safely.

Section 3Removing water

Drying removes moisture so microbes cannot grow easily. Salting and sugaring also reduce available water by drawing water out of food and microbial cells. In Jamaica, salted fish is a familiar example of preservation by salt.

Section 4Acid and air control

Pickling uses acid, often vinegar, to make conditions unsuitable for many microbes. Canning seals food in airtight containers after heat treatment, preventing new microbes from entering. In plain words, safe preservation blocks spoilage from starting again.

Section 5Safe storage matters

Preserved food still needs correct storage. Check expiry dates, damaged tins, swollen cans, mould, bad smells, and broken seals. Food that looks or smells unsafe should not be tasted to 'check' it.