Final answer:
The principle to not touch the part of a dish or utensil that could contact a guest's mouth is a basic rule of hygiene to prevent contamination, which is similar to laboratory safety practices such as using sterile equipment and proper hand washing.
Step-by-step explanation:
The statement "Never touch a part of a dish or utensil that a guest's mouth might touch" is indeed true, especially in a professional setting where hygiene and guest safety are of utmost importance. This is a basic principle in food safety and handling to prevent cross-contamination and the spread of germs. In a similar vein, when working in a laboratory setting, strict protocols must be followed to maintain sterility and safety. For instance, using gloves when handling a sterile pipette is essential to prevent contamination. Additionally, thorough hand washing and the proper cleaning of equipment, such as test tubes and beakers, are crucial to prevent unwanted chemical reactions. One must also exercise caution when dealing with heat sources, and always communicate promptly with the supervising teacher regarding any incidents, to ensure a safe and controlled environment.