Sour cream is made of whole milk, cream, and distilled white vinegar or lemon juice.
Sour cream, which has a fat content of around 20 percent, is made by mixing cream with a lactic acid culture; the bacteria thickens and sours it.
It can also contain stabilizers, like gelatin or rennin, which aid in the thickening.
Sour cream is a fermented dairy product that is created when lactic acid bacteria is introduced to cream, denaturing the whey proteins in the cream and thickening the liquid.
If the sour cream is bad and smells bad or tastes bad and has bacteria in it then you could get sick from the expired sour cream.
However if it' just expired and has been refrigerated and no mold or bacteria has grown in it and it smells okay and tastes okay then the sour cream should not make you sick.
Getting sick from expired sour cream is possible but only if the expired sour cream is actually bad and has grown bacteria and mold or has turned bad smelling.
Sour cream can still be good for a week or two weeks past the expiration date as long as the sour cream has remained refrigerated during that time.
The expiration date just means that the sour cream is not fresh anymore and it may not taste as good as before and the texture might change some when the sour cream has reached it's expiration date.
But the sour cream is still safe to eat even when it has expired as long as it's been refrigerated.
If the sour cream tastes bad, smells bad or has any mold growth in the sour cream or the sour cream has become watery looking them throw it out.
Otherwise the expired sour cream will be safe to eat.