It’s important to follow common sense and any dates or instructions for how a food should be stored before and after opening it. We should always look for signs of spoilage (food going off) like mould, smells, browning or curdling to tell if it’s becoming unpleasant or unsafe. Fresh foods usually keep longer if they are refrigerated or frozen.
Packed foods are often labelled with dates that help us use them safely and get the best out of them. If we eat something a bit after its Best Before date, providing it looks and smells ok it will probably still be safe … but may not be as good. But if we eat something after its Use By date it might make us sick, so we should never do this. Baked On and Packed On dates tell us how fresh (but not how safe) some foods are.
Fridge – Sliced meats and leftover meals should generally be used within 2–3 days; sugary foods like jams, sauces or chutneys can last several weeks after opening.
Freezer – In theory frozen foods can last a very long time, but in practice it’s important to follow instructions about how long to keep bought frozen food and how to defrost and cook it safely. And even freezing won’t kill all food poisoning bacteria, or many viruses.
Packed foods – Start to deteriorate (become worse) in quality once they’re opened. Pathogens (bacteria or virus causing disease) can also get into these foods now and start growing. Instructions like: “Once opened keep refrigerated between 2–4 ⁰C and eat within 7 days” or “Once opened store in an airtight container” are there to help us stay safe and get the best out of foods.
Packaged foods with a shelf life of less than 2 years must have a date mark. (The shelf life is how long the manufacturer reckons the unopened food can last before deteriorating, i.e. without changes in colour, texture, flavour, odour, or nutrients). These dates assume the food is being stored unopened and in line with instructions. There are two main date types:
Best Before (BB or BBF) is the date after which a food may lose some of its quality or nutritional value. It’s safe to sell and eat for a bit longer provided it’s unopened and not showing signs of spoilage. People who make food (“manufacturers”) sometimes put BBFs on foods with a shelf life over 2 years (like canned goods) to help shops and consumers use up old stock first.
Use By is the date by which a food must be eaten and after which it is illegal to sell it. It’s less commonly used than BBF and up to manufacturers to decide whether they need one. It’s only used if there’s a health risk to consuming a food after a certain date. This risk is often from micro-organisms (especially bacteria) increasing over time to levels that could cause food poisoning before there are any obvious warning signs of spoilage. You’ll usually see them on foods like sliced salamis and ham, seafood, sushi, and some chilled or deli foods like fresh sandwiches, pasta and sauces.
Why not see where you can find them?
Baked on dates on breads, or packed on dates on other foods (like packed vegetables, sandwiches, and some meats) give an idea of freshness, but are not the same as a BBFs or Use by dates.
Packer’s codes, lot or batch numbers are there to show where a food comes from so it can be tracked or recalled if there are any issues with quality or safety.
Check out some foods to see how many different types of dates and codes you can see!
Food Standards Australia New Zealand, December 2013. “User Guide to Standard 1.2.5 – Date Marking of Food. Retrieved from: http://www.foodstandards.govt.nz/code/userguide/pages/datemarking.aspx 19 September 2017.
Ministry for Primary Industries, 8 June 2016. “Is it Safe to Eat?” Retrieved from: http://www.mpi.govt.nz/food-safety/food-safety-for-consumers/is-it-safe-to-eat/ 25 September 2017.
Ministry for Primary Industries, July 2017. “Foodborne Disease in New Zealand 2016”. MPI Technical Paper No 2017/46. Retrieved from: http://www.foodsafety.govt.nz/science-risk/human-health-surveillance/foodborne-disease-annual-reports.html 25 September 2017.
Ministry of Health, July 2012. “Food and Nutrition Guidelines for Healthy Children and Young People (Aged 2–18 years): a Background Paper. Partial Revision February 2015.” Retrieved from: http://www.health.govt.nz/system/files/documents/publications/food-nutrition-guidelines-healthy-children-young-people-background-paper-feb15-v2.pdf 19 September 2017.
Ministry of Health, October 2015. “Eating and Activity Guidelines for Healthy Adults. Retrieved from: http://www.health.govt.nz/system/files/documents/publications/eating-activity-guidelines-for-new-zealand-adults-oct15_0.pdf 18 September 2017.
Food Standards Australia New Zealand, n.d. “Use By and Best before Dates”. Retrieved from: http://www.foodstandards.govt.nz/consumer/information/pages/howtoreadfoodlabels/usebyandbestbeforedatesaus/Default.aspx 19 September 2017.
Ministry for Primary Industries, NZ, “Food Recalls”. http://www.mpi.govt.nz/food-safety/food-safety-for-consumers/food-recalls/
Ministry for Primary Industries, NZ, “Food Safety Resources for Teachers”. Retrieved from: http://www.mpi.govt.nz/food-safety/food-safety-for-consumers/tips-for-food-safety/food-safety-resources-for-teachers/