Pasteurisation and Heat Treatment

Caviar pasteurisation is a validated treatment intended to control specified microbial hazards and extend refrigerated shelf life, commonly by heating the sealed final container. It is not commercial sterilisation, and the word “pasteurised” does not establish that a jar can be stored at room temperature.

What caviar pasteurisation means

Pasteurisation must be defined by its target organism, required reduction and validated operating conditions, not simply by a bath temperature. FDA describes seafood pasteurisation as usually occurring in the hermetically sealed finished container, meaning a container designed to prevent microorganisms entering. “Usually” matters: the packaging sequence is not a universal definition.

Codex CXS 291-2010 covers salted sturgeon roe and specifies 3 to 5 g salt per 100 g of finished product. It does not prescribe a universal pasteurisation schedule. Its process definition requires conditions preventing pathogenic microorganisms from growing; Codex is an international reference standard, not automatically binding national law.

For the surrounding production sequence, see caviar processing. The consumer distinction belongs in fresh, unpasteurised and pasteurised caviar.

Validate the product, not the water bath

A processor needs evidence that the slowest-heating part of the product receives the required treatment. Container dimensions and material, fill weight, formulation, initial temperature and equipment loading can change heat penetration. Codex's 2016 fish committee processing text explicitly connects caviar pasteurisation conditions to these variables rather than offering one recipe.

Seal integrity and cooling water hygiene also matter because contamination after heating can defeat the treatment.

The same text describes treatment in cans or jars, followed by immediate cooling to 0 to 4 °C (32 to 39.2 °F). According to Codex, pasteurisation conditions depend on the container, fill weight and equipment. Seal integrity and cooling water hygiene also matter because contamination after heating can defeat the treatment.

Al-Holy and colleagues tested radio-frequency heating at 60, 63 and 65 °C (140, 145.4 and 149 °F) in sturgeon and salmon roe inoculated with three strains of Listeria innocua, a research surrogate for Listeria monocytogenes. Faster heating than a water bath and successful microbial reductions were experimental findings, not a transferable commercial schedule.

Botulism controls are separate from a Listeria kill step

Reduced-oxygen packaging can permit Clostridium botulinum growth and toxin formation unless effective barriers are maintained. A treatment validated against vegetative bacteria, such as Listeria, need not destroy bacterial spores. Extending shelf life also lengthens the period during which surviving organisms could grow.

FSA guidance for vacuum or modified atmosphere packed chilled foods identifies additional controlling factors for shelf lives exceeding 10 days at 3 to 8 °C (37.4 to 46.4 °F). These include a treatment equivalent to 90 °C (194 °F) for 10 minutes, pH no higher than 5.0 throughout the food, water activity no higher than 0.97 throughout the food, at least 3.5% salt in the aqueous phase throughout the food, or a validated combination of factors.

Those are alternative control approaches within that guidance, not instructions to apply all of them or a mild caviar heating schedule. Its scope covers England, Wales and Northern Ireland; Scottish operators should confirm the approach with Food Standards Scotland.

Water phase salt measures salt relative to the product's water and salt together: 100 × salt percentage ÷ (salt percentage + moisture percentage). It is not the nutrition label's total salt percentage. FDA's 2022 lumpfish-caviar warning letter illustrates the distinction: the agency required controls beyond a Listeria-directed pasteurisation step, including verified formulation and refrigeration controls.

What changes in texture, colour and flavour

Heat treatment changes more than microbial counts. Rocchetti and colleagues examined eight commercial caviars from six sturgeon species using sensory assessment, texture measurements and untargeted metabolomics, an analysis of many small molecules. Their study found that pasteurisation affected chemical and sensory profiles in white sturgeon caviar.

A separate Swedish study compared two live-harvested sturgeon caviars: one stabilised using warm water, the other using pH-adjusted cold water. Cold processed samples required greater force in groups of 25 grains; warm processed samples scored slimier, with no significant instrumental colour difference. Because the processing systems differed, these results do not isolate heat alone.

The professional implication is to assess the finished process, not promise a universal sensory penalty. Compare bead rupture, free liquid, colour and flavour against an appropriate untreated control, then repeat the assessment through the proposed shelf life.

Treatment and storage are different specifications

A glass jar does not identify the treatment or establish shelf stability. FDA's 2022 warning letter documents refrigerated pasteurised lumpfish caviar in glass jars.

Codex specifies 2 to 4 °C (35.6 to 39.2 °F) during packaging, storage and retail, and -4 to 0 °C (24.8 to 32 °F) for wholesale storage and transport. These are storage conditions, not serving temperatures; pasteurisation does not authorise a warmer service allowance. Product-specific shelf life and instructions after opening remain separate specifications.

Which processing rules apply

In the EU, Regulation (EC) No 852/2004 establishes hygiene and HACCP duties, including controls for heat treatment in hermetically sealed containers. Regulation (EC) No 853/2004 adds requirements for foods of animal origin, including fishery products. Neither replaces the operator's responsibility to validate the actual product and process.

Regulation (EC) No 2073/2005 governs microbiological criteria. Since 1 July 2026, its amendment by Regulation (EU) 2024/2895 extends the requirement for Listeria monocytogenes not to be detected in 25 g throughout shelf life for relevant growth-supporting ready-to-eat foods unless competent authorities accept evidence that Listeria remains within 100 colony-forming units per gram throughout shelf life.

Northern Ireland follows the applicable EU requirements; Great Britain has its own assimilated and amended legislation. The FSA identifies the July 2026 Listeria change as applying in the EU and Northern Ireland, so it should not be presented as an automatic Great Britain amendment.

In the US, 21 CFR Part 123 requires seafood hazard analysis and, where necessary, a HACCP plan. Refrigerated pasteurised caviar does not become a low-acid canned food merely because it occupies a sealed jar. Part 113 concerns thermally processed low-acid foods in hermetically sealed containers. FDA distinguishes refrigerated or frozen pasteurised seafood from shelf stable retorted products governed by Part 113.

An ambient-stable acidified formulation may instead engage Part 114: classification depends on formulation, equilibrium pH, water activity and storage conditions. Part 114 also excludes foods stored, distributed and retailed under refrigeration. A processing authority should resolve the classification before an ambient product is launched.

Labelling and additional markets

In the EU, Regulation (EU) No 1169/2011 requires treatment information alongside the food's name where omission could mislead, as well as relevant storage instructions. This is a conditional information duty, not grounds to claim a universal caviar-specific “pasteurised” wording rule. Great Britain and Northern Ireland need separate legal checks.

For US specifications, distinguish a substantiated pasteurisation claim from refrigeration labelling used as a HACCP control.

Canada's CFIA expressly distinguishes ready-to-eat pasteurised caviar from commercially sterile canned fish in its product categories. Japan classifies salted or heat-treated fishery foods as processed foods for labelling.

High pressure is documented, but remains process-specific

Ovissipour and colleagues reported a laboratory study of white sturgeon caviar inoculated with Listeria innocua. Treatment at 400 MPa in three five-minute cycles at room temperature produced a reported six-log reduction, equivalent to a millionfold reduction. This conference abstract establishes experimental work on caviar, not commercial validation, spore control or a proven shelf life.

What to request before release

Request the validated process and target organism, heat-penetration evidence, formulation limits, cooling specification, closure checks, calibrated monitoring records and shelf-life substantiation. The finished label and distribution temperature must match that evidence. A batch record showing only water-bath temperature is not a complete product safety case.

Where to go next

• Caviar Microbiology: for the organisms and their behaviour.
• Caviar Food Safety: Listeria, Botulism and Who Should Take Care: for risks to consumers.
• How Long Does Caviar Last? Unopened vs Opened: for interpreting storage life after opening.