EFSA Opinion indicates that wild-caught fresh- or seawater fish must be considered at risk of containing viable parasites of human health hazard if these products are to be eaten raw or almost raw (EU No 1276/2011). There are various ways of reducing such risks, e.g. either by freezing of the product for a certain while or by thermal treatment. Marinated herring produced in Norway, does not go through any of these treatments (i.e. thermal or freezing).
During the production of marinated herring, the most important factor for the survival of Anisakis larvae is the concentration of salt in the marinade. Previous studies have shown that a reduction of salt in the marinade will lengthen the survival of Anisakis. Currently, there are no studies that describes the effects of NaCl/K-replacement and Anisakis survival.
This study is a co-operation with SINTEF – SFA and is part of a larger project, financed by FHF, and aim to generate increased knowledge about the salt tolerance of Anisakis, due to the request for the reduced usage of salt during production of marinated herring products.
The project aim to investigate how reduced/changed salt concentrations in marinades affect the survival of Anisakis larvae in marinated herring products.
The project contains two main parts:
- Various concentrations of NaCl and K – in vitro trial using petri dishes.
- Sandwich-trial where a known amount of Anisakis larvae are sown into herring filets.
The effect of storage temperature will be tested (-4°C, 0°C and 2-4°C). Chilled storage at -2°C may affect the survival of Anisakis larvae.
Live Anisakis larvae will be picked from herring, and depending on the infection status, we may also consider getting larvae from pollock. Pollock are larger fish and will most likely be infested by larger/older Anisakis, and it will then be possible to check the effect and size/age.
The difference marinades will be supplied by SINTEF/producer.