Which of the following is not an antibiotic?

Citric acid is a weak organic acid with the formula -CHO. It is a natural preservative or conservative which occurs naturally in citrus fruits and is also used to add an acidic or sour taste to foods and drinks. Griseofulvin is an orally administered antifungal drug. It is used both in animals and humans, to treat fungal infections of the skin and nails. Whereas cephalosporins are a group of broad spectrum, semi-synthetic beta-lactam antibiotics derived from the mould Cephalosporium. Streptomycin is an antibiotic (antimycobacterial) drug, the first of a class of drugs called as aminoglycosides to be discovered,