Steak tartare is a classic dish, and so is sushi.
Do not eat raw (or even undercooked) poultry or pork or wild game meats. Do not eat raw PRE-ground beef.
You don't need to worry about bacteria per se (and lemon or lime juice wouldn't really kill that anyway). Just buy steak, you can gnaw that any old way you want to ... but if you'd like to actually enjoy it the next time you're having a salad very thinly -- like paper thin -- slice a steak (if you pop the steak into the freezer for a little while until it starts to slightly freeze you will find it much easier to cut), and add the "chipped" steak to your salad.
You'll discover that uncooked beef, like uncooked fish, has LESS flavor.
Finally, here's a pretty basic Steak Tartare recipe (courtesy of E. Legasse):
Assorted fresh greens
12 ounces beef tenderloin or sirloin
Worcestershire sauce
Hot pepper sauce
Salt
Black Pepper
2 tablespoons drained capers
2 tablespoons Dijon mustard
1/3 cup minced red onion
1/3 cup finely chopped parsley
2 eggs
4 slices of white bread, crusts removed, brushed with olive oil and lightly toasted
Extra-virgin olive oil
Garnish 2 plates with the fresh greens.
Place the beef on a cutting board and finely chop with a very sharp knife. Season to taste with Worcestershire sauce, hot pepper sauce, salt and black pepper. Shape the meat into 2 patties of equal size and center each on a plate of fresh greens.
Around each meat patty arrange half of the capers, Dijon mustard, red onion and parsley. Carefully break the 2 eggs, reserving the yolk and half of each shell. Place the yolks in their eggshell cups, then sit an egg cup in the center of each patty. Serve the steak tartare with toast points, olive oil, and hot pepper sauce and Worcestershire sauces on the side.