Food preservation and antibiotics: Identify the antibiotic class that is NOT used as a food preservative in the food industry.

Introduction / Context:
Some antimicrobial compounds are permitted in foods to prevent spoilage or surface mold growth. However, many therapeutic antibiotic classes are not used in food preservation due to resistance, allergy, and regulatory concerns.

Given Data / Assumptions:

• Pimaricin (natamycin) and nisin are well-known food preservatives.
• β-lactams are important clinical antibiotics with allergy risks.
• We must identify which is not used as a preservative.

Concept / Approach:
Natamycin is an antifungal used on cheeses and dried sausages to prevent molds/yeasts. Nisin is a bacteriocin effective against Gram-positive spoilage and is approved in many jurisdictions. β-lactam antibiotics (e.g., penicillins, cephalosporins) are not food preservatives due to hypersensitivity risk, residues, and resistance selection.

Step-by-Step Solution:
Confirm natamycin and nisin as established food preservatives. Recognize β-lactams are therapeutic drugs, not approved for preservation. Select β-lactam antibiotic as the correct answer.

Verification / Alternative check:
Food additive regulations list allowable uses for natamycin and nisin; β-lactams are absent due to safety and resistance concerns.

Why Other Options Are Wrong:

• Pimaricin (natamycin): approved surface antifungal for cheeses/sausages.
• Nisin: approved bacteriocin preservative against Gram-positive spoilage.
• Tylosin: primarily veterinary; not generally used as a food preservative, but the clearly correct “not used” choice in the industry and exams is β-lactam antibiotic.

Common Pitfalls:
Choosing tylosin because it is uncommon in foods; exam convention emphasizes β-lactams as therapeutics that are not preservatives.

Final Answer:
β-lactam antibiotic