People who have a disease but do not show symptoms are called:

Individuals who have a disease but do not exhibit any symptoms are referred to as carriers. In the context of infectious diseases, carriers can transmit the pathogen to others without being aware that they are infected themselves. This is particularly important in the field of food safety and public health, as asymptomatic carriers can pose a risk for the spread of pathogens through food or other means without realizing it.

Understanding the concept of carriers is crucial for implementing effective food safety practices and controlling the spread of infectious diseases. For instance, food managers must be aware of the risks associated with asymptomatic individuals in food handling and preparation to prevent potential outbreaks.

In contrast, the other options do not accurately describe individuals with this characteristic. The term "lucky" does not provide a meaningful definition in this context, "hygienists" refers to professionals focused on hygiene and sanitation practices, and "PCOs" likely pertains to pest control operators, which is unrelated to the concept of disease carriers. Thus, "carriers" is the term that correctly identifies individuals carrying a disease without showing symptoms.