Need some suggestions for any kind of food/appetizer that won't spoil while sitting out all day?

a veggie tray with a non-dairy dip like basil hummus, or this dip recipe:

Use a food processor to blend a block of silken tofu, a diced cucumber, some lemon juice, and salt and pepper.

i would try some

fried pickles, you can fry them the night before and they can sit out all day with/out dip (NO DAIRY -EGG BASED DIP) so that leaves Hummus, Mustards, anything Vineagar based,

brownies. cookies, chips, veggies, fruit with peanut butter,

bruschetta(SUPER EASY) stail bread sliced on angle, drizzle a little olive olive ontop, pop in oven to make sure its ROCK HARD(important) then slice up FIRM tomatoes about 6 or 8 then add either fresh/powder garlic =4 tablespon, 2 tablespoon red pepper flakes or hot sauce, salt and pepper to taste or 2 teaspoons of each, and 1/4cup oil(olive if you have it) any kind just not sesame oil(too strong) and add 4tablespoons of vinegar(balsamic if you have) if not any (if you have ITALIAN DRESSING USE THAT inplace of the O&V all together! add some green herbs,i.e basil, marjoram, oregano, thyme, whatever you want. and add 1 onion finely diced add everything together let it marinate for atleast 1 hour and then spoon it onto the bread. it will go far in terms of serving ALOT for CHEAP and ITS ALOT easier then it looks on here. and it can LASTS for HOURS because the bread soaks up the juices of the tomatoes and O&V because it is so hard and it softens the longer it sets! PREP time is NOTHING!

lastly I would say vegetable eggrolls, or fried greenbeans or grilled asparagus those are the best things that I can come up with that DONT NEED ANY kind of refrigeration. ENJOY!

If you want to make something like potato salad or cole slaw, just put the bowl in a larger bowl filled with ice. It's a good way to keep BBQ staples cool all day.

you can make mexican dip; take two (8oz) blocks of cream cheese, two cans of chili (one with beans and one without), and shredded mexican cheese. spread the cream cheese out onto the bottom of a baking dish, pour all the chili over it. put a nice layer of mexican cheese over the chili (enough to cover it) then you can either cook it it the oven at 425F until the cheese is fully melted and heated all the way through or you can pop it in the microwave for 5-7 minutes (until cheese is fully melted and heated through). andyou can leave this out all day, but have something to cover it with so flys or bugs dont land in it, and serve with chips.

you can't go wrong with brownies and cookies! just the easy, simple stuff. chips, brownies, cookies, maybe some kind of dip to go with the chips (look for a sausage or bacon dip in a cookbook).

hope you have fun!

A NICE MEDITERRANEAN RICE SALAD. this was just an idea, hope this helps.