All food has a limited shelf life which will vary depending on the type of food, how it is packaged and how carefully it is transported and stored.
The storage life of food products is influenced by many factors. Some foods spoil because microbes can still grow. Other foods are affected by chemical changes such as a slow development of brown colour and/or flavour changes, and rancidity in fats.
The environmental conditions under which food is stored also influence storage life. Water uptake or loss can affect texture and other food attributes. Warm storage temperatures, bright light, air (containing oxygen), and high humidity all shorten storage life – and ultimately affect your product quality, price and marketability.
Appropriate packaging and refrigeration can substantially reduce the rate at which food will deteriorate. Low temperatures slow the growth of microorganisms and the rate of chemical (including enzymic) changes in food.
Maximising shelf life
Many factors are critical in maximising shelf life, such as ingredient selection, processing techniques and packaging, as well as handling practices, storage protocols and cold chain transport solutions.
It is important to check that your storage room or refrigerator is operating correctly. Your thermometer should show a temperature below 5°C in the main section of the refrigerator.
Avoid crowding stored products in the refrigerator, ensure good air circulation around each item. Proper storage not only keeps your products in good condition and safe from the growth of food poisoning bacteria, but saves you money because it reduces waste.
The responsibility of determining the shelf life of a food, and thus its best-before or use-by date, lies with the manufacturer/packer.
The most direct way of doing this is to conduct properly constructed storage trials under realistic, defined conditions. This may not be possible for smaller manufacturers, in particular those just entering the market.
Retailers may also have their own demands about shelf life of particular product categories especially those with a relatively short shelf life. Food technologists, based at SARDI, can use a range of methods and models to investigate shelf-life and use-by dates.
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The legal requirement for manufacturers of packaged foods to open date mark foods was introduced in Australia in 1978. This followed similar moves internationally and the publication of a standard by the Codex Committee on Food Labelling. It was argued by consumer groups that with the rapid changes occurring in food manufacturing, packaging and retailing, consumers could no longer rely on traditional wisdom and habits to dictate how long a food may be stored.
It is an offence to sell packaged food past its use-by date and this form of date marking is tied to food safety.
For more information, visit CSIRO’s Food Science.
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CSIRO storage advice
The environmental conditions under which food is stored directly relates to storage life.