Final answer:
Individuals who become ill from eating spoiled food may lack c) Bitter receptors, which are critical for detecting the bitter tastes often associated with toxins in spoiled food.
Step-by-step explanation:
If an individual becomes poisoned from eating excessive amounts of spoiled food, the kind of receptors they might lack are likely to be bitter receptors. Bitter receptors on the tongue are responsible for the detection of bitter substances, which often are indicative of toxins and spoiled food. Thus, not being able to detect bitter tastes could hinder an individual's ability to avoid potentially harmful foods. In humans, there are five primary tastes: sweet, sour, bitter, salty, and umami, each with its corresponding type of receptor. The sour receptors are sensitive to the acidity in substances, which is why they are often associated with the pH of saliva. It's important to note that the taste for umami, which signals the presence of proteins in food, is also crucial for diet regulation. Therefore, the bitter receptors that detect potentially toxic substances in spoiled food are essential for preventing food poisoning and ensuring the ingestion of safe and nutritious food.