A low peroxide value can be misleading
Peroxides are intermediates. In an advanced oxidation state they have already decomposed, so peroxide value falls while anisidine value climbs. Reading peroxide value alone can make a badly oxidised oil look fresh, which is why TOTOX exists.
Antioxidant treatment is part of the specification
For fish meal, fish oil, high-fat meals and rendered fats, the antioxidant used, its dose and the date of treatment are as much a part of the specification as the oxidation indices themselves. Untreated marine cargo has a materially shorter usable life.
Typical industrial reference values
| Peroxide value | Low single digits desirable | Primary oxidation products |
| Anisidine value | Tracks secondary oxidation | Rises as PV falls back |
| TOTOX | Combined oxidation history | Preferred for marine oils |
| Free fatty acids | Hydrolytic rather than oxidative | Indicates handling and storage history |
Indicative industry reference values for orientation only — always contract against the delivered lot.
What to verify
- —Peroxide value, anisidine value and free fatty acids together, with the sampling date
- —Antioxidant declaration: type, dose, treatment date
- —Temperature history during voyage and storage
Typical risks
- —Vitamin A and E destruction in the finished feed
- —Palatability rejection, particularly in aqua and pet diets
- —Self-heating in bulk marine ingredients
Common mistakes
- —Specifying peroxide value only
- —Ignoring the elapsed time between certificate date and delivery date
Frequently asked questions
Why does oxidation matter beyond the fat itself?
Oxidation propagates. It destroys fat-soluble vitamins and pigments in the same feed, reduces intake, and generates compounds that stress the animal — so the cost is rarely limited to the fat fraction that was measured.
Related topics
Fat content sets the energy density of an ingredient and, together with fatty-acid profile and oxidation status, determines both nutritional value and storage stability.
Verifying remaining shelf life at intake — production date, storage history and stability indicators — prevents paying full price for material that has already spent most of its usable life in transit.
Storage history — how long, at what temperature and humidity, in what structure, alongside what else — explains most of the gap between a production certificate and the quality actually delivered.
Build a structured RFQ with the parameters, tolerances and verification steps written in — free for buyers.
Start your RFQTechnical parameter names and analytical method references are kept in English because they are quoted verbatim in contracts, certificates and international standards.
Educational reference. FeedMatch Group does not rank, recommend or endorse manufacturers.
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