Canned foods: purchasing and storing
Airtight sealing of foods in containers in association with heat and/or chemical treatments is a very effective method of preserving food. Foods such as fruit, vegetables, meat, fish, or a combination of these foods (e.g. meat and vegetable condensed soup, sauces and fruit salad) can be stored safely in airtight sealed containers.
Commonly, foods in airtight sealed metal containers (such as aluminium and tinplate) are called canned foods. Airtight sealed containers may also be made from glass jars, plastic tubs, flexible pouches and UHT cartons. This fact sheet is intended to help consumers use these products as part of a balanced, varied and safe diet.
Are the containers safe?
Containers used for the airtight sealing of foods do not affect the quality or safety of the contents. However, if the container is damaged during or after manufacture, the safety of the food may be affected.
How are canned foods made commercially?
Canned foods are washed, prepared and filled into metal containers along with a canning fluid (e.g. water, salted water or fruit juice). The food is heat treated to produce a commercially sterile shelf-stable product with an air-tight (vacuum) seal. Heat treatment kills organisms that may spoil the food or cause food-borne illnesses. Contents remain commercially sterile until the container is opened and the vacuum seal is broken.
How long can I keep canned foods?
Always check the label when buying food. Date marks on the labels of canned foods will provide you with information on when the product can be sold or consumed.
In Australia and New Zealand, canned foods that have a shelf-life of less than two years require a ‘best-before date’ (date mark) on the label. A ‘best-before’ date applies to the quality of the product. It is safe to purchase and consume the product after its ‘best-before’ date, however the food may not be at its peak quality.
Canned foods with a shelf-life of more than two years do not need a ‘best before’ date. These foods do not carry a date mark as it is very difficult to determine a meaningful date when the shelf life is two years or longer.
When checking for date marks, look for clear, obvious printed numbers. Food regulations require ‘best before’ dates to be distinguishable, expressed in chronological order (i.e. month, year), and provided in uncoded numbers.
As long as the container remains intact, canned foods have a long shelf life even at room temperature. The sealed containers prevent contamination of food by organisms that can spoil the contents or cause illness to people during transportation and storage.
While canned foods do not change suddenly, slow changes do occur in the container and food quality may change over time. The storage life depends on a number of factors, including conditions of storage and the nature of food. As a general rule, the best shelf life will be obtained when canned foods are kept in a cool, dry place. For best results, it is recommended that your supplies of canned food are refreshed periodically.
How do I store canned foods at home?
Check the label of the product for any storage instructions. If the label has storage instructions, ensure that the food is stored accordingly at the point-of-purchase.
Generally, canned products are designed to be stored at room temperature. If more stringent storage conditions are required for health and safety reasons, then the label must state these storage conditions.
If instructions are not provided on the label, then store in a cool dry place. Handle containers carefully to avoid denting or other damage. Rotate food in your pantry by using older stock first.
How do I select canned foods?
Always check the label when buying food. Date marks on the labels of canned foods will provide you with information on when the product can be sold or consumed. In addition, food containers should be inspected for:
- swelling and/or leakage
- rust and scratches
- broken tamper-evident seals
- dented or damaged containers
- damaged seams (joins)
Do not purchase the food if you see any of these problems.
Before opening
Inspect the container as outlined in ‘How do I select these foods?’ before use. If there are signs of damage, do not use or even taste the food.
Wipe or wash the top of the container before opening. Always use a sharp clean can opener and wash the opener after every use.
Practice good hygiene as if you were handling fresh food – keep all food preparation surfaces and implements clean, and wash hands in warm soapy water before preparing food.
After opening
If the contents have an unusual odour or colour, or if you notice that the inside of a metal container (or lid) is rusted, throw out the contents. Do not taste.
Once opened, canned foods are often highly perishable. Opened canned food should be treated in the same manner as regular food, and should not be stored any longer than its uncanned version. If not used immediately, the contents of the opened container should be emptied into clean plastic or glass container, covered and stored in a refrigerator.
What should I do if I suspect problems with these foods?
You should report any doubtful product to the manufacturer. If you have any concerns about a particular food, you could alert the health department in your state, territory or region.
What about foods in containers other than cans?
Just as cans are used to process and store foods that would otherwise be perishable, other packaging options are often used, such as:
- glass jars
- plastic tubs
- flexible pouches
- UHT cartons
Foods in these packages are often processed in a similar manner to canned foods, and like canned foods are usually highly perishable after opening. Check for date marks on these products in the same way as for canned foods.
As with product in any packaging, the food should be discarded without tasting if it shows signs of damaged packaging or sealing.
Glass jars and plastic tubs are almost always vacuum sealed. Any product where the lid is not clearly sealed and typically ‘sucked down’ – should not be used.
Any flexible pouch or carton that has leaked or is swollen or under pressure should not be opened.
Products with a short shelf life
Flexible pouches and cardboard cartons can also be used for short-life products in addition to long-life products. Short-life products must be sold and stored in a chilled state, and be consumed before their expiry date. Always check the label when buying food. Date marks on the labels of packaged foods will provide you with information on when the product can be sold or consumed.
Further information
Food Science Australia. Storage life of Foods – Fact Sheet 2005. Available at: http://www.foodscience.csiro.au/storagelife2.htm
Canned Food Industry Association.Website available at: http://www.can-news.com.au/
For general food safety information, contact the Food Safety Information Council at: http://www.foodsafety.asn.au/
This document is intended as a guide only: legal requirements are contained in the Australia New Zealand Food Standards Code, other relevant food legislation and other applicable laws. This information in this document should not be relied upon as legal advice or used as a substitute for legal advice. You should exercise your own skill, care and judgement before relying on this information in any important matter.