Whenever we go shopping for packed or processed foods, there are a couple of dates printed on the bottles, pouches or boxes which helps us to determine the freshness of the product but many of us aren’t clear what the different dates mean and when is it safe to consume the food item and when to chuck them in the bin. In this article, I will simplify the common terms related to food shelf life for you.
The Institute of Food Science and Technology defines shelf life as “the period of time during which the food product will remain safe; be certain to retain its desired sensory, chemical, physical, microbiological, and functional characteristics; where appropriate, comply with any label declaration of nutrition data, when stored under the recommended conditions.” In simple English, a food product will be in its best form during its self life and after that it may start to deteriorate. Food companies test perform shelf life tests for new products which are ready to be launched by keeping its samples under common environmental conditions and testing them after a plan period for changes in sensory, microbial and physical parameters overtime. The results of these tests help determine a products ‘best before’ and ‘expiry’ dates.
This the date on which the raw or unprocessed or intermediate food became the final product.
Date of packaging:
This the date on which the product was packed in the appropriate container.
Sell by date:
This is a guide for retailers and informs them of the date by which the product should be sold or removed from shelf life. Typically one-third of a product's shelf-life remains after the sell-by date for the consumer to use at home therefore, the product is safe to consume after the date.
Best before date:
This the date is about quality, not safety. When the date is passed, it doesn't mean that the food will be harmful, but it might begin to lose its flavour and texture. For example, foods which are fried and baked may tend to become soggy and sour and carbonated beverages may become flat past this date.
Use-by or expiry date:
This the more important date to be mindful of after which food item may exhibit faster deterioration in its quality and safety. This doesn’t necessarily mean that if a food item expires tonight, it’ll be poisonous tomorrow morning but the risk factor does go up considerably.
Use within X days after opening:
Some food labels have after opening instructions which suggest for how long you can keep the product after you open the packaging, this is because the product was packaged under modified atmosphere in which the ratios of oxygen, nitrogen and carbon dioxide are different than normal. For example, raw meat, fish an poultries are usually packed under modified air in which ratio of oxygen is considerably lower whereas that of nitrogen is higher, after opening the ratio of oxygen increases and thus the meat starts to get darker sooner as compared to when it was packed.
Instructions such as ‘keep refrigerated after opening’, ‘keep in a cool and dry place’, ‘defrost thoroughly’ or other specific cooking instructions are to provide you with best suggestions which shall help avoid any quality or food safety deterioration after you’ve purchased the item.
The takeaway box
I strongly recommend that you read your food labels when shopping but if you are short of time then atleast read the use-by or expiry date ‘cuz getting food poisoning won’t be cool at all. Although the food may probably still be safe to consume after their expiry or use-by date, especially ones which are highly processed as they are low in protein and water content while having higher amounts of sugar and salts which act as preservatives in conjunction with specific added preservatives. But foods such as packaged meat, milk, eggs, fruits and vegetables should not be consumed well before their use-by date as they have a higher risk of developing lethal microorganism which may lead to food poisoning. We usually ignore handling, storing and cooking instructions on the pack but if you want to enjoy the foods at their best then you should definitely give them a quick read. Hopefully by now you are clear on the different dates on the packaging, this confusion leads to a lot of food to be wasted every year as people throw away perfectly fine food which have passed their ‘sell-by’ or ‘best before’ date.
References and further reading:
Institute of Food Technologists (IFT). "The difference between 'Use-By' 'Sell-By' and 'Best-By' dates." ScienceDaily. ScienceDaily, 15 April 2015 <www.sciencedaily.com/releases/2015/04/150415203336.htm>.
Newsome, R., Balestrini, C.G., Baum, M.D., Corby, J., Fisher, W., Goodburn, K., Labuza, T.P., Prince, G., Thesmar, H.S. and Yiannas, F. (2014), Applications and Perceptions of Date Labeling of Food. Comprehensive Reviews in Food Science and Food Safety, 13: 745-769. doi:10.1111/1541-4337.12086
Food Labelling Requirements - Date Of Manufacture Or Packing And Best Before Or Use By Date. [online] Food Safety Helpline. Available at: <https://foodsafetyhelpline.com/food-labelling-requirements-date-of-manufacture-or-packing-and-best-before-or-use-by-date-module-7/#:~:text=%E2%80%9CDate%20of%20manufacture%E2%80%9D%20means%20the,c> [Accessed 25 October 2020].
Zweep, C., 2018. Determining Product Shelf Life - Food Quality & Safety. [online] Food Quality & Safety. Available at: <https://www.foodqualityandsafety.com/article/determining-product-shelf-life/?singlepage=1> [Accessed 25 October 2020].