It's not necessary for sandwiches to be chilled at all times unless you're in a food establishment.
If you're serving the food in a food establishment to customers then the sandwiches must be kept chilled at all times.
However at home sandwiches can remain at room temperature for around 2 hours before they should be chilled or refrigerated.
Although some sandwiches are good at room temperature for up to 4 to 6 hours.
You can make a sandwich the night before and then store them in sealed Ziploc bags to prevent them from drying out.
Then store the sandwiches in the Ziploc bags in the refrigerator overnight.
A sandwich in a Ziploc bag is good for around 4 to 6 hours depending on what is on the sandwich when it's left out at room temperature.
When kept in the refrigerator the sandwich in the Ziploc bag is good for around 4 days.
If you pack a lunch and have sandwiches in a Ziploc bag they should be eaten within 4 hours to 6 hours or you run the risk of getting food poisoning.
Most people will eat their packed lunch or sandwich in Ziploc bag soon enough so that it does not grow the bacteria.
Although packing your sandwich in a Ziploc bag will prevent your sandwich from being exposed to the air, it will also lock in condensation.
To store your sandwich without leaving it soggy, wrap it in parchment paper or waxed paper.
Most sandwiches can last from 3-5 days in the fridge.
The sandwiches that last the longest are the ones with dry and less perishable ingredients, such as shredded cabbage and carrots, hard cheeses, tough greens like kale, etc.
Meat and chicken sandwiches can last an average of 4 days in the fridge too.
According to food safety guidelines you can only keep the sandwich at room temperature for 4 hours.
That's how long it takes food that should be refrigerated to grow a dangerous amount of bacteria and germs.