How many days is the shelf life of train lunch boxes?

How long is the shelf life of train lunch boxes?

Have you ever taken a high-speed train? I haven't had the chance to take a high-speed train, but my friends who have taken a high-speed train told me that the boxed lunches on the train are quite delicious. Since I often take the train, I have become interested in the shelf life of the boxed lunches on the train, so I checked the shelf life of the boxed lunches on the train. Now let me tell you about the shelf life of the boxed lunches on the train!

( 1 ) The shelf life of the lunch boxes on trains says they can last for six months, but this is only true if they are vacuum packed, sterilized and dust-free.

( 2 ) Generally speaking, the shelf life of an unpacked train lunch box is only about 2 days, because it cannot prevent infection by bacteria, just like home-cooked meals.