In the example, you'll notice I'm checking that the entire string, "bizobj =" is on one line in the file, hence the regex bol and eol matching. But, otherwise, if it's just a straightforward string, you would be correct.
ETA: The reason I think my solution might be silly is because I keep thinking there is a (PERL) regex expression for a string occurring exactly zero times, like there is a way to specify a string match exactly once.