Final answer:
Food handlers can be (d) asymptomatic, which means they do not exhibit symptoms but can still carry and spread diseases like typhoid fever caused by S. typhi. They can unknowingly contaminate food or water, posing a health risk through their status as active carriers. The incubation period for foodborne diseases can vary greatly, affecting when symptoms might appear.
Step-by-step explanation:
Food handlers can be asymptomatic, meaning they show no noticeable symptoms of illness but carry disease for a long time. When people are capable of transmitting a disease without exhibiting any overt symptoms, they’re often referred to as active carriers. An example of an asymptomatic carrier is an individual who carries S. typhi, which causes typhoid fever. These individuals may house the bacteria in their gallbladder or intestinal epithelium, shedding it through their feces and contaminating food or water without being aware of their infectious state.
Some diseases may be subclinical, with no apparent symptoms, such as infections by certain viruses like herpes simplex, which remains dormant in many hosts. The incubation period—the time between the consumption of contaminated food and the first appearance of symptoms—varies for foodborne diseases. The incubation period for a foodborne disease can range from a few hours to several days or even longer. During this time, microbes generally pass through the stomach and into the small intestine, where they can multiply and potentially cause illness.