A hot (120° F--49° C--or more), wet utensil transfers its gender to a countertop upon which it is placed, but only at the area of contact.
Status of Countertop

1. Gender status of the countertop:
   • D'rabanan, the countertop area of contact remains that gender until kashered (as long as the countertop material is kasherable).
   • D'oraita, the countertop reverts to kosher-neutral/pareve after 24 hours.
   Note If the utensil and counter were not wet (nor dirty with food) at the area of contact, there is b'di'avad no transfer of gender.
2. If you put a hot, wet utensil of the opposite gender on that same spot, that counter space may become non-kosher.

Status of Utensils
If the counter had not had a hot, wet utensil/container of food of the opposite gender placed on the same spot within 24 hours of each other, the utensils may be used and the utensils are still kosher.
Status of Food
This does not apply to food that is directly placed on the counter, in which case the food might become non-kosher.