Why does my milk bottle lid have two dates

I'm living in Switzerland at the moment. I've just come back from a short holiday and realise I've left some milk in the fridge.
The top oddly has two dates. One marked a which was yesterday and one marked b which isn't for another week.
Knowing that swiss milk tends to be nuclear and last a while I tried the milk and...it does seem a bit off. The water and the solid have seperated slightly in some places. It doesn't smell but it does taste odd.
I think it's fair to say I shouldn't use it. I should do without milk for a day.
However the question remains: what are these two dates?
I guessed best before and use before but that seems wrong.
Best Answer
I haven't been across the border in a while, but I just double-checked via image search.
Most dairy products (and other foods with a short shelf life) in Switzerland have or had two dates, a "sell-by" and a "best before" or "consume by" date.
Often, there will be a descriptive text, sometimes even in German, French and Italian, but there are brands that omit the text, probably because the average Swiss consumer knows how to interpret the double dates.
An example of a non-dairy product is this:
Interestingly, there was a debate about the double date, centered around the confusion of consumers and their impact on food waste. Some supermarket chains like Coop have removed the "sell by" date since 2016, Migros insists on keeping it. (Source, in German)
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Quick Answer about "Why does my milk bottle lid have two dates"
These allow milk producers to tell consumers when the peak freshness of the product is. They do not indicate the exact date the milk will go bad." These labels vary from state to state, so it's not unusual for things to get a little confusing and for milk to be thrown out while it's still good and safe for consumption.Why does milk have 2 dates on it?
This date is provided to the grocery store by the milk processor to ensure that they sell the milk at its peak, so you can enjoy its delicious taste. Milk is generally good up to a week after its \u201csell by\u201d date. This date is for you.What does the date on a milk bottle mean?
This date indicates when to consume the milk by for the best quality. Sell by. This date can help stores with inventory management, as it tells when to sell the milk by to ensure the best quality. Use by. This date is the last day you can expect the product to be at peak quality.What does the date stamped on a milk carton mean?
Milk producers apply these dates to give consumers an idea of when their milk will taste best, or when a store should stop selling the milk because it might not reach consumers in optimal freshness. Experts say the milk in the carton, though, is safe even after the stamped date has passed.Can you drink milk after expiration date?
Milk is generally safe to consume after the expiration date for at least a couple of days. People will typically be able to tell when milk is bad, as the smell and appearance indicate any spoilage. The type of processing that the milk undergoes can affect how long it will stay fresh.When Should I Stop Using Bottles?
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