Preserving Food: Methods, Benefits & Storage

Written by John Mason Dip.Hort.Sc., Jade Sciacia B.Sc. and the expert staff of ACS Distance Education. 

Food preservation is a great way to store food for later use. It prevents spoilage by inhibiting the growth of microorganisms such as bacteria, fungi, and yeasts and limits enzyme reactions.

There are many reasons why we may choose to preserve food:

🥦 To extend shelf life by delaying deterioration.

🥦 To use what we have produced in our gardens.

🥦 To retain nutrients – the faster we can preserve food the more nutrients are retained.

🥦 For convenience – you can have plentiful supplies in your pantry year -round.

🥦 To improve the flavour by introducing extra flavours as you preserve.

🥦 To reduce food waste.

🥦 To make home made gifts for friends and family.

🥦 To start a small business.

THE MAIN METHODS

There are 5 main methods of food preservation:

Canning or bottling - this method involves placing foods into a jar or can and heating foods to a temperature where microbes are destroyed and enzymes are inactivated. Canning food involves removing air from the container forming a vacuum seal. Fruits are best cooked in their juice
which also inhibits microbial growth. Canned goods will store for several years.

Pickling - this method involves the production of acid from foods via the process of fermentation or involves placing foods into brine (a high salt solution) or into vinegar which is too acidic for microorganisms to grow. The shelf life for pickled goods is from 3 weeks to 18 months.

Making jams and jellies - sugar is added to foods making it difficult for microbes to grow. Fruits are also cooked in which also inhibits microbial growth. Shelf-life is 1 -2 years.

Freezing – this method involves placing food in an environment which is too cold for microbes to grow. Freezing food places them in temperatures of -18 degrees Celsius inhibits microbial growth
and allows for longer term food storage. Vegetables are best blanched before freezing into zip-lock, airtight, bags. Best for Fruits, vegetables (usually blanched first), meats, and prepared meals. Frozen foods have a shelf-life of 6 – 9 months.

Drying foods - this is one of the most ancient methods of preserving food. Today we use heat, vacuum drying (which pulls the water out of food), osmotic drying and freeze drying. At home you can use a microwave for some herbs or a domestic food-dehydrator. Best for: Fruits, vegetables, herbs, and jerky. Properly stored dried fruit will store for 12 months and veggies and herbs 6 – 12 months.

Smoking – this method combines heat, dehydration, and antimicrobial smoke to improve flavour and shelf life, most commonly used for meats.

Check out our Food Preserving courses

🥗 🍅 🍯 Tip: When choosing fruit and vegetables, pick products that are at the best stage of maturity i.e. do not pick under-ripe fruit or immature vegetables and discard fruit and vegetables that show any sign of disease. And always follow food safety guidelines when preserving food.