Pus indicates a body's reaction to infection. It's a medical term and shows something's wrong.

Medical Condition

Never use 'pus' to describe food; it suggests contamination and can cause disgust.

Avoid in Food

Use 'pus' mainly in medical or health contexts; elsewhere, it can be inappropriate or graphic.

Context Sensitive

 provide a nutritional boost to young larvae that feed on leaf rich but sodium poor diets she also notes that some researchers hypothesized blood feeding evolved from animal related behaviors such as feeding on tears dung and pus

Vampire Moths Discovered...

 arrived to issue another challenge. Knowing what had happened to their fathers, the twins nevertheless answered the call, trekking through deep caverns and across rivers filled with scorpions, blood, and pus,

The twins who tricked...

 who was so ravaged by infection that his scalp oozed pus and doctors had to take out an eye, was infected by doing something very simple. He walked into his garden and scratched his face on a thorn.