Expiry date, shelf life, best before: what the dates on food packaging mean

Expiry date, shelf life and best before: what is the difference?

Term	What it is	Example
Expiry date	A point in time. This is what Taiwanese law requires on the package	Expiry: 15 March 2027
Shelf life	A length of time, counted from the date of manufacture	Shelf life: two years
Best before	A Japanese labelling term with no definition in Taiwanese law	Best before: 2027.03.15

The first two are the ones people mix up. Shelf life tells you how long something keeps; the expiry date tells you until which day. A packet of biscuits made on 15 March 2025 with a two-year shelf life has an expiry date of 15 March 2027.

In other words, shelf life only gives you an answer once you add it to the manufacturing date, while the expiry date gives you the answer directly. That is why Taiwan’s rules require the expiry date: nobody should have to do arithmetic in the supermarket aisle.

What does an expiry date actually promise?

Taiwan’s Food and Drug Administration defines the expiry date as the final date on which packaged food keeps its product value under the stated storage conditions. “Product value” means more than not having gone off. It covers three things:

• Safety and hygiene
• Nutritional quality
• Sensory quality — taste, smell and appearance

Take a bottle of fresh milk labelled “keep refrigerated” with an expiry date of 15 March. The producer is promising that until 15 March, as long as it stays refrigerated and unopened, it is safe, has not lost significant nutritional value, and still tastes the way fresh milk should.

That promise has two conditions: the package is unopened, and you store it the way the label says. The same bottle left out for an afternoon, or opened five days ago, may be undrinkable before its date. Once it is open, the clock that matters is the separate instruction to “consume within X days of opening”.

If the expiry date only shows a month, which day does it end?

Under Article 13 of the Enforcement Rules of Taiwan’s Act Governing Food Safety and Sanitation, an expiry date should normally show the day, month and year. Products with a shelf life of three months or more may show only the year and month, and the date then runs to the last day of that month.

So “Expiry 2027.03” means the product is good until 31 March 2027, not 1 March.

This is a common misunderstanding. Throwing something out at the start of March because it says “2027.03” wastes a whole month. Dry goods, tinned food and condiments — the long-life items that most often use this format — are also the ones most often thrown away early.

Best before and use by in Japan: are they the same as an expiry date?

Best before (shōmi kigen) is a labelling scheme defined by Japan’s Consumer Affairs Agency. It marks the date until which flavour and quality are at their best; passing it does not mean the food is immediately unsafe. Japanese labels also use a second date, use by (shōhi kigen), for food that deteriorates quickly — and that one does mean you should not eat the food afterwards. The two are often confused, but they mean very different things.

Taiwanese law has no concept of a best-before date. According to past guidance from Taiwan’s FDA, imported food labelled only with a best-before date, where the importer cannot show that it is equivalent to Taiwan’s definition of an expiry date, is in principle treated as an expiry date.

In practice: for imported products bought in Taiwan, read a best-before date as an expiry date. Do not stretch it on the grounds that “in Japan it would still be fine”.

Is food safe to eat after its expiry date?

Start by separating two things: the law regulates sellers, not you.

Once a product passes its expiry date, businesses may no longer manufacture, sell, import, export or display it. That is the shop’s obligation. The law says nothing about what you do with the bottle of soy sauce in your cupboard that expired two days ago — that is your judgement.

Three things are worth considering:

• Has it been opened? Unopened, properly stored dry goods, tins and condiments generally keep far better than opened ones. After opening, the countdown that matters is “use within X days of opening”, which is usually printed somewhere else on the pack.
• Has it been stored correctly? Something that needs refrigeration and has sat at room temperature for a few hours may already be unsafe, even before its date. The temperature and layout of your fridge matter too — see how to organise your fridge so food does not expire.
• Is anything wrong with it? Mould, discolouration, an off smell, a bulging tin or a puffed-up package have nothing to do with the date. If you see any of them, do not take the risk. Taiwan’s FDA also warns against cutting the mould off and eating the rest: mould threads spread into the food where you cannot see them.

What about expired medicine and cosmetics?

Be more cautious with medicine and cosmetics, and go by what a pharmacist or the label says.

Taiwan’s Food and Drug Administration explains that expired medicine not only gradually loses potency but may also have deteriorated in ways that raise safety concerns. The trouble compared with food is that you may believe a dose is working when it no longer has the intended effect — and you usually cannot tell by looking.

Taiwan’s FDA offers two practical rules of thumb:

• The limit after opening arrives before the expiry date. Oral or topical medicines are generally best not used more than 3 to 6 months after opening, and eye drops or oral liquids not more than 1 month after opening.
• If it looks wrong, throw it out. Tablets that have changed colour, crumbled, absorbed moisture or smell different should be discarded, even if they are still in date.

When in doubt, asking a pharmacist is the quickest answer. Do not flush expired medicine down the toilet or sink; many pharmacies will take it back.

Worried about things expiring? The real problem is forgetting, not judging

Most things that expire do not do so because you misjudged them. They expire because you forgot they existed — the jar of sauce at the back of the fridge, the cold medicine at the bottom of the first-aid box, the sunscreen in the bathroom cabinet.

The date on a package only helps when you look at it. Solving this for good does not take better judgement; it takes keeping the dates somewhere that reminds you on its own, before they arrive.