If I got take out food today and bit into metal shavings, can I file suit?

Where you injured? And, if so, how badly? There are two components to being able to sue. First, the other party must be at fault, and from what  you write, there's a good chance the take out place is at fault--there should not be metal shavings in food. Second, there must be injury and/or economic loss (e.g. medical costs, lost wages, etc.) The legal system compensates people for their injuries or losses--it does not, except in very special cases (which this would not be) award money over and beyond the extent of injuries or losses. So if you were fortunate enough to not be injured, or to only suffer something very minor (e.g. a cut lip), there's nothing to sue for--you can't recover enough money to make it worthwhile.