Spatulas made of which material must be discarded after each use?

The correct choice is that spatulas made of porous material must be discarded after each use due to hygiene and safety concerns. Porous materials can harbor bacteria and other pathogens because their microscopic structure allows for the absorption of liquids and potentially harmful substances. When a spatula made of porous material is used on one client, it could be contaminated, and using it again on another client poses a risk of cross-contamination.

In contrast, plastic, wood, and metal spatulas can often be reused if they are properly sanitized between uses. Plastic spatulas, for example, are typically non-porous and can be disinfected effectively. Wooden spatulas, while they do have some absorption properties, can often be disposed of after a single use in sensitive environments but do not carry the same level of risk as porous materials. Metal spatulas can be cleaned and sanitized thoroughly, making them safe for repeated use. Thus, options involving plastics, wood, or metal do not carry the same critical health risk associated with porous materials, making porous material the correct answer for disposal after each use.