DK200970102A

DK200970102A - Methods and apparatus for removal of parasites and oil from fish liver

Info

Publication number: DK200970102A
Application number: DK200970102A
Authority: DK
Inventors: Pedersen Soeren
Original assignee: Bornholms As
Priority date: 2009-08-27
Filing date: 2009-08-27
Publication date: 2009-12-09
Also published as: DK177153B1

Claims

1. A method for removal of nematodes from fish liver, preferably cod liver, said fish liver comprising liver meat at least partly surrounded by connective tissue membrane attached to said liver meat, said nematodes being situated on an inside of said membrane in respective depressions of said liver meat, said method being characterized by comprising the steps of treating said fish liver with steam for a period of time sufficient to allow for said connective tissue membrane to contract, thereby pulling out said nematodes from said respective depressions, and further treating said fish liver with steam for a period of time sufficient to allow for said connective tissue membrane to be released from said liver meat.

2. A method according to claim 1, wherein said steam has a temperature of 90 to 110°C, preferably 95 to 105°C, more preferred 99 to 101°C, preferably said steam is in the form of free steam, i.e. with a temperature of about 100°C and/or a total steam treatment time lies within an interval from 2 to 90 seconds, preferably 20 to 70 seconds, more preferred 40 to 60 seconds, most preferred 45 to 55 seconds.

3. A method according to claim 1 or 2, wherein said treatment steps are carried out in a steam chamber, pieces of fish liver being transported on a conveyor band, preferably comprising a wire grid, through said steam chamber, steam dischargers above and below said conveyor band preferably discharging steam into said steam chamber.

4. A method according to claim 3, wherein said steam treatment steps are carried out in a steam treatment zone defined on its upper side by an internal steam dome surrounded on its sides and at its upper end by a vapor extractor extending into a vapor outlet.

5. A method according to any one of claims 1 to 4, wherein after said steam treatment steps the step of washing, rinsing or spraying off any remains of membrane and nematodes, preferably by means of water, is carried out.

6. An apparatus adapted for carrying out the method according to any one of the previous claims, characterized in that it comprises a fish liver steam treatment chamber adapted for steam treating pieces of said fish liver, said fish liver steam treatment chamber comprising a steam treatment zone and a vapour extraction zone, said steam treatment zone being adapted for steam treatment of said fish liver and being defined on its upper side by an internal steam dome surrounded on its sides and at its upper end by said vapour extraction zone, the latter being defined by a vapour extractor extending into a vapour outlet, a fish liver wire grid conveyor band adapted for transporting pieces of said fish liver through said steam chamber via a fish liver inlet and a fish liver outlet, and said steam treatment zone comprising a number of steam dischargers provided above and below said conveyor band, said steam dischargers being adapted for discharging free steam into said fish liver steam treatment chamber.

7. An apparatus according to claim 6, further comprising a water washing station positioned along said conveyor band, said water washing station being adapted to wash, rinse or spray off any remains of membrane and nematodes of steam treated fish liver exiting said fish liver steam treatment chamber.

8. A method for reducing the oil content of fish liver, preferably cod liver, said fish liver comprising liver meat at least partly surrounded by tissue membrane attached to said liver meat, said method being characterized by comprising the steps of at least partly detaching said tissue membrane from said liver meat, and treating said fish liver with humid air of high relative moisture content for a period of time between 5 and 30 minutes, preferably 10 and 25 minutes, most preferred 15 and 20 minutes, said humid air having a relative air humidity of 80 to 100%, preferably 90 to 100%, more preferred at least 95%, most preferred at least 98 or 99%, and a temperature of 40 to 70°C, preferably 50 to 50°C, more preferred 53 to 57°C, most preferred about 55°C.

9. A method according to claim 8, wherein said humid air is heated and humidified by means of steam from a steam discharger, preferably by means of a steam lance with a moisture-heat distributer, such as a sponge, which primarily distributes moisture on air form, i.e. not on steam form, and/or said step of treating said fish liver with humid air comprises simultaneously smoking said fish liver, and/or said method also comprises the steps according to any one of claims 1 to 5.

10. An apparatus adapted for carrying out the method according to claim 8 or 9, characterized in that it comprises a fish liver air treatment chamber adapted for treating pieces of fish liver with hot humid air, a fish liver wire grid conveyor band adapted for transporting pieces of said fish liver through said fish liver air treatment chamber via a fish liver inlet and a fish liver outlet, and a steam discharger, preferably a steam lance with a moisture-heat distributer, such as a sponge, said steam discharger being adapted for distributing moisture on air form, i.e. not on steam form, and heat into said fish liver air treatment chamber. Internationalt Patent-Bureau A/S