After you read this article, you will always clean the handle of your grocery cart with a disenfectant wipe.
http://www.usatoday.com/yourlife/health/2011-03-02-grocerycarts_N.htm (http://www.usatoday.com/yourlife/health/2011-03-02-grocerycarts_N.htm)
72% of carts were tested positive for fecal matter. :o