Is It Permissible to Purchase Fruits and Vegetables from a Place without a Kosher Certificate?

Greetings, In Israel, if the produce consists of fresh vegetables, it is permitted to eat them after separating terumot and ma'asrot (tithes and offerings) without reciting a blessing. Similarly, for fresh fruits, it is permitted to eat them after separating terumot and ma'asrot. Regarding the prohibition of orlah (fruit from a tree less than three years old), one may be lenient due to the presence of multiple doubts: they may primarily not be orlah; they may be from areas outside the Land of Israel (outside of which there is no prohibition of orlah); or the halacha may follow the opinion that permits leniency in Israel at this time. Nevertheless, one who is stringent upon himself will be blessed (see Yabia Omer, Vol. 6; Yoreh De'ah, siman 24). Outside of Israel, it is permissible to eat fresh fruits and vegetables without separating terumot and ma'asrot since there is no obligation to separate them there (Shulchan Aruch, Yoreh De'ah, siman 99, se'if 1). Regarding orlah outside Israel, it is simply permitted because the doubt about orlah outside Israel is allowed (Shulchan Aruch, ibid., siman 285, se'if 9). 

Blessings, Hillel Meirs