In Schnuphase v. Storehouse Markets, 918 P.2d 476 (Utah 1986), the plaintiff was a business invitee in a grocery store who slipped and fell on a scoop of ice cream dropped by another customer. 918 P.2d at 477. Discussing store owners' duty of reasonable care in slip and fall cases, we quoted a previous decision, Allen v. Federated Dairy Farms, Inc., 538 P.2d 175 (Utah 1975), identifying two classes of such cases.The first class, to which Schnuphase belonged, was that involving temporary unsafe conditions. Id. Cases in this class, the Court explained, require actual or constructive notice for liability to attach: "It is quite universally held that fault cannot be imputed to the defendant so that liability results therefrom unless two conditions are met: (A) that he had knowledge of the condition, that is, either actual knowledge, or constructive knowledge because the condition had existed long enough that he should have discovered it; and (B) that after such knowledge, sufficient time elapsed that in the exercise of reasonable care he should have remedied it." Id. (quoting Allen, 538 P.2d at 176). The second class of cases, however, involves some unsafe condition of a permanent nature, such as: in the structure of the building, or of a stairway, etc. or in equipment or machinery, or in the manner of use, which was created or chosen by the defendant (or his agents), or for which he is responsible. In such circumstances, where the defendant either created the condition, or is responsible for it, he is deemed to know of the condition; and no further proof of notice is necessary. Id. (quoting Allen, 538 P.2d at 176).