Patricia Carroll filed a complaint against appellee Winn Dixie alleging that Winn Dixie's negligence caused her personal injuries. The trial court denied Winn Dixie's motion for summary judgment, and granted a certificate of immediate review. We granted Winn Dixie's application for interlocutory appeal, and we now reverse.

In a "slip and fall" case, "not only must the plaintiff show that the defendant had knowledge of the presence of the foreign substance, but the plaintiff must also show that he was without knowledge of its presence. The customer must exercise ordinary care for his own safety, and must by the same degree of care avoid the effect of the merchant's negligence after it becomes apparent to him or in the exercise of ordinary care he should have learned of it. He must make use of all his senses in a reasonable measure amounting to ordinary care in discovering and avoiding those things that might cause hurt to him." (Citations and punctuation omitted; emphasis supplied.) Alterman Foods v. Ligon, 246 Ga. 620, 623 (272 SE2d 327) (1980).

We assume, without deciding, that Winn Dixie had constructive knowledge of the hazard in question. However, if a plaintiff is unable to prove either element of the Alterman test, a failure of proof results. Smith v. Wal-Mart Stores, 199 Ga. App. 808, 810 (406 SE2d 234) (1991). In this case, the evidence demands a finding that Carroll failed to exercise ordinary care for her own safety. She acknowledged in her deposition testimony that the unidentified foreign substance on the floor was visible "if you stood there and looked at it," that she did not look down at the floor as she traveled the same path three times, and that nothing distracted her or diverted her attention.