A sandwich that has any meat or perishable ingredients can sit out unrefrigerated for up to 2 hours.
If the sandwich has no perishable ingredients then it can sit out longer but it should be kept in a plastic bag to keep the bread from drying out.
If the sandwich has meat such as lunch meat then it should not be left out at room temperature longer than 2 hours.
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.