A dishwasher comprising: a tub at least partially defining a washing chamber; a liquid spraying system (54, 56) supplying a spray of liquid to the washing chamber; a liquid recirculation system (50, 34) recirculating the sprayed liquid from the washing chamber to the liquid spraying system (54, 56) to define a recirculation flow path; and a liquid filtering system (64,176) comprising: a housing (62, 702) defining an interior (82, 718) and having an inlet port; a rotating filter (530,708) having an upstream surface and a downstream surface and located relative to the recirculation flow path such that the recirculation flow path passes through the filter from the upstream surface to downstream surface to effect a filtering of the sprayed liquid; and a first artificial boundary (580, 706) in the form of a shroud (580, 706) extending along a portion of the filter (530, 708) and defining an interior within which the rotating filter (530, 708) is located, and having an inlet opening facing downstream to the recirculation flow path, to form a backflow zone where the liquid flows from the downstream surface to the upstream surface; wherein the first artificial boundary (580, 706) is located adjacent the upstream surface of the rotating filter (530, 708) to create a high pressure zone (596, 786) at a location that is rotationally in front of the inlet opening such that the backflow zone is positioned relative to the inlet opening to retard entry of foreign objects in the liquid into the inlet opening (70, 770) along the recirculation flow path. a tub at least partially defining a washing chamber; a liquid spraying system (54, 56) supplying a spray of liquid to the washing chamber; a liquid recirculation system (50, 34) recirculating the sprayed liquid from the washing chamber to the liquid spraying system (54, 56) to define a recirculation flow path; and a liquid filtering system (64,176) comprising: a housing (62, 702) defining an interior (82, 718) and having an inlet port; a rotating filter (530,708) having an upstream surface and a downstream surface and located relative to the recirculation flow path such that the recirculation flow path passes through the filter from the upstream surface to downstream surface to effect a filtering of the sprayed liquid; and a first artificial boundary (580, 706) in the form of a shroud (580, 706) extending along a portion of the filter (530, 708) and defining an interior within which the rotating filter (530, 708) is located, and having an inlet opening facing downstream to the recirculation flow path, to form a backflow zone where the liquid flows from the downstream surface to the upstream surface; a housing (62, 702) defining an interior (82, 718) and having an inlet port; a rotating filter (530,708) having an upstream surface and a downstream surface and located relative to the recirculation flow path such that the recirculation flow path passes through the filter from the upstream surface to downstream surface to effect a filtering of the sprayed liquid; and a first artificial boundary (580, 706) in the form of a shroud (580, 706) extending along a portion of the filter (530, 708) and defining an interior within which the rotating filter (530, 708) is located, and having an inlet opening facing downstream to the recirculation flow path, to form a backflow zone where the liquid flows from the downstream surface to the upstream surface; wherein the first artificial boundary (580, 706) is located adjacent the upstream surface of the rotating filter (530, 708) to create a high pressure zone (596, 786) at a location that is rotationally in front of the inlet opening such that the backflow zone is positioned relative to the inlet opening to retard entry of foreign objects in the liquid into the inlet opening (70, 770) along the recirculation flow path.