How to talk about contamination in wort, beer, and food in general, to make it clear it's about bacteria?

Sometimes unwanted microorganisms find a way to food, and start to ferment it. Common term for this is "infection", but some people argue it is invalid, because, well, food isn't alive. Other term for this is "contamination", but that does not differentiate bacteria issue and lead or iron issue.

Is there a valid, not uncommon, and easily recognizable word for bacteria, wild yeast, mold etc contamination? One that does not include heavy metal contamination or sanitizer contamination?

Solution 1:

Biological contamination, not a single word, but the most common term.

Food contamination can occur in many different ways. Four main causes of food contamination are:
1. Not washing hands
2. Cross-contamination
3. Improper storage and cooking temperatures
4. Contamination by animal waste

Contaminants can be [commonly] divided into three categories:

Physical: wood, metal, glass, paint chips, hair
Chemical: cleaning chemicals, maintenance chemicals, pest control chemicals
Biological: micro organisms, insects, rodents, birds

Source: Safe Food Handling

Biological contaminants — Business Dictionary

Living organisms (such as bacteria, enzymes, fungi, viruses) or their products that can be hazardous to animal or human health if inhaled, swallowed, or otherwise absorbed into the body.

If a person/animal consumes "contaminated food", they may get "infected" by the microorganisms.

_{Related: Biological contamination — TFD}

^{The contamination of a building environment caused by bacteria, molds and their spores, pollen, viruses, and other biological materials}