Influence of tetracycline antibiotics on the spoilage of herring (C. Harengus)

The effect of two antibiotics (chlor‐ and oxy‐tetracycline) on the spoilage of whole iced herring is studied. Spring and summer herring were improved (taste panel assessment, determination of total volatile bases) by the antibiotics, but autumn herring were unaffected. This is attributed to a seasonal variation in the nature of the bacterial flora present on the fish. Peroxide values were higher for oil from treated compared with that from untreated fish, but the production of free fatty acids and volatile fatty acids was not affected. The production of some free amino‐acids was higher in the treated compared with the untreated fish. An attempt is made to explain these results.