What exercise can screen potential tasters effectively?

The exercise that can effectively screen potential tasters is a sensory discrimination test. This type of test is designed to evaluate an individual's ability to perceive differences in sensory attributes, such as taste, aroma, and texture. In the context of taste, it helps determine an individual's sensitivity to various flavors and their ability to detect subtle distinctions between them.

Sensory discrimination tests often involve presenting participants with samples that vary in specific attributes, allowing them to identify differences between those samples. This is critical in assessing whether someone is a competent taster, as it gauges their sensory acuity and ability to discern flavors accurately.

Other options, while related to sensory perception, do not specifically assess the taster's ability to differentiate between tastes in the same way. A color identification test focuses on visual acuity, a taste tolerance challenge measures an individual's maximum exposure to certain tastes, and a written quiz on flavors tests knowledge rather than sensory perception. Therefore, the sensory discrimination test is the most appropriate choice for screening potential tasters.