It is not surprising that you have a positive Hep A titer. Just this morning I was explaining this issue to a nurse here at work. Hep A is more common then the average health care worker realizes. You can pick it up in many food sources, needle sticks are not a common way to acquire it. I have recommended Hep A vaccine for any travelers within the US since the vaccine came out.
It appears that Advisory Committee on Immunization Practices is beginning to catch up to me and is now recommending Hep A vaccine for “persons with medical, behavioral, occupational, or other indications” which I identify as travel in the US and frequent use of restaurants.
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5140a5.htm
Nursing News