Method for treatment of meat

The invention relates to a method for the treatment of meat from fish or other aquatic, poikilothermic animals and comprises a flavour- influencing process, which preferably comprises treatment of the meat with an extract of wood or of a wood product, and a heating process comprising treatment of the meat with microwaves, preferably in a microwave oven.

Such a method is known from EP 1,296,569, examples 6 and 7. The purpose of the method disclosed therein is i.a. to produce smoked fish such as fresh, smoked salmon without using smoking, which creates a relatively dry smoking coating on the surface of the fish meat, which coating contains carcinogenic substances.

A disadvantage of the method according to said EP 1,296,569, ex- amples 6 and 7 is that both the market for smoked fish products and the food authorities are hesitant to accept the use of extracts such as those mentioned above for the flavouring of food products.

A further disadvantage of this method is that it does not provide directions as to suitable means for dispersing the extract in the fish meat.

The object of the invention is to provide a method that allows for production of smoked meat products with a significant reduction in the amount of time and number of processing steps used, and in which the disadvantages mentioned above are avoided. On this background, the object is met by the method according to the invention being characterized in that the flavour-influencing process comprises smoking and/or treatment of the meat with an extract of wood or of a wood product, the extract or solution hereof being sprayed onto the meat, or the meat being treated with ultrasound in a solution of the extract.

Surprisingly, with the method according to the invention it is achieved that, using smoking, a satisfactory smoke flavour can be obtained and a satisfactory penetration of the smoke flavour in the inside of the meat at a fairly brief smoking, typically 8-16 % of the smoking

time used in conventional smoking; that, using sprayed-on extract or solution, a satisfactory smoke taste and a satisfactory distribution of said smoke taste can be achieved, even with a brief, subsequent heating process; and that, using treatment of the meat with ultrasound in a solution of the extract, a satisfactory smoke flavour can be achieved and a satisfactory penetration of the smoke flavour in the inside of the meat with a fairly brief ultrasound treatment.

For the sake of taste and longevity of the finished product, a salting process is preferably carried out prior to the flavour-influencing process and the heating process.

Preferably, the salting process is carried out as a wet-salting with treatment of the meat with ultrasound in a saline brine, direct contact between meat and ultrasound-emitting surfaces being avoided.

Firstly, a significant reduction of the treatment time for salting is achieved hereby, and, secondly, significantly better possibilities for automation of the process, as compared to dry-salting and conventional wet-salting, are achieved.

Preferably the extract used is extracted from wood, charcoal or wood tar, as such extracts give a smoke taste that is considered by ex- perienced tasters to be as good as, almost as good as or better than the smoke taste obtained by smoking. Appropriate extracts are disclosed in the abovementioned EP 1,296,569 and in the related divisional EP 1,726,216.

According to the invention, the flavour-influencing process can comprise only smoking of the meat.

In this case, it has surprisingly been found that a fairly brief smoking is sufficient to impart a satisfactory smoke flavour to the meat. In the method according to the invention, the smoking time in production of cold-smoked products can be reduced without further ado to for in- stance 8-16% of the smoking time used in conventional cold-smoking, at the same time as a satisfactory smoke flavour in the meat being achieved.

Furthermore, it has surprisingly been found that, though sufficient penetration of the smoke flavour is only achieved in a relatively thin,

outer layer of the meat with the said very brief smoking, the smoke flavour will have penetrated the entire thickness of the meat after the heating process. This is assumed to be due to a strongly accelerated diffusion of the smoke flavour, originating from the excitement of water molecules and others that is brought about by the treatment of the meat with microwaves during the heating process.

Finally, when such a brief smoking is used it has surprisingly been found that no formation of a smoking coating can be detected, and therefore it must be expected that no formation of carcinogenic sub- stances, which can otherwise be detected in smoking coatings, has taken place.

According to the invention, the flavour-influencing process can alternatively comprise only treatment of the meat with ultrasound in a solution of the extract in a suitable dissolvent such as edible oil. In this case, it has surprisingly been found that a treatment time that is very brief, even compared to the brief smoking mentioned above, is sufficient to impart a desired smoke taste to the meat.

It has also surprisingly been found in this case that, though penetration of the smoke flavour is achieved only in a relatively thin, outer coating of the meat, using the said very brief ultrasound treatment in the flavour-influencing process, the smoke flavour will have penetrated the entire thickness of the meat after the heating process. This is assumed to be due to a strongly accelerated diffusion of the smoke flavour, originating from the excitement of water molecules and others brought about by the treatment of the meat with microwaves.

In this connection, the flavour-influencing process is preferably carried out in an ultrasound vat, in which the meat is transported through the vat by a traversing conveyor.

Hereby, reduced processing time and reduced need for handling of the meat is achieved - and thus reduced need of operating personnel.

According to the invention, the flavour-influencing process can also comprise any combination of smoking of the meat and treatment of the meat with ultrasound in a solution of the extract. Hereby advantages corresponding to those mentioned above are achieved.

According to the invention, the flavour-influencing process and the heating process are preferably carried out simultaneously in a treatment device that is suitable for carrying out both these processes.

This embodiment of the invention is particularly of importance when the flavour-influencing process comprises smoking, as the smoking oven and microwave oven are then built as a combined oven in which the microwave treatment and the heating process are carried out in an atmosphere of smoke. Thus, the flavour-influencing process and the heating process are combined to a single process in a single process stage. However, use of smoke extract by spray application also seems to be advantageous in this case.

Firstly, a reduction of the number of processing stages and thus a significantly shorter processing time is achieved hereby, and secondly a more compact process line is achieved. Furthermore, tests have shown that, in this embodiment, an unexpected, favourable synergy between the smoking process and the heating process is achieved, so that the processing time can be reduced more than initially expected.

In a preferred embodiment, the heating process comprises a brief treatment of the meat with microwaves (and/or treatment at low power), when a meat product corresponding to cold-smoked fish is desired, and a longer treatment (and/or treatment at high power), when a meat product corresponding to heat-smoked fish is desired.

According to the invention, it is possible in this way to produce both these products without having to expose the products, in particular the heat-smoked product, to an intensive smoke influence. Thus, it becomes possible to combine a flavour-influencing process of sufficiently short duration to only just achieve a desired smoke flavour with a heating process of a sufficiently long duration to achieve a desired heat treatment and thus desired structure and texture.

Finally, the heating process is preferably carried out in a microwave oven of the pass-through type.

Hereby it is achieved that the oven can be included in an effective manner in an automated production plant, and that a uniform and re-

producible treatment of the meat pieces is ensured.

E X A M P L E S

EXAMPLE 1

Fresh sides of salmon with skin were laid with the skin side facing upwards on a table covered with salt, whereby the salt adhered to the meat side. The sides of salmon were placed on a grill on a frame with the skin side facing downwards and were allowed to remain for a period of time of between 2 and 12 hours, depending on the desired degree of salting.

Then the salt was rinsed off with water and the sides of salmon were placed in cold storage for a stretch of time to level out, drip off and for evaporation of surplus water. The frame was rolled into a smoking oven and the sides of salmon were smoked by cold-smoking, the smoking time though being shortened from 8-12 hours to 60-80 minutes. Following smoking, no smoking coating could be detected.

After another stay in cold storage, the sides of salmon were placed in a skinning machine known per se for removal of the skin side. The sides of salmon were then placed on a conveyor that transported the fish through a microwave oven of the pass-through type in a continuous movement.

At the exit side of the oven, the sides of salmon were removed manually from the conveyor, put in crates and driven to cold storage.

Finally, the smoked and microwave treated sides of salmon were removed from the cold storage room and placed on a conveyor to a slicing machine and from there on via the conveyor to weighing cells, where the sides were weighed out to desired packet sizes and were packed under vacuum or with a protecting gas.

By this process, a product corresponding to fresh smoked salmon (i.e. cold-smoked) in slices was provided.

EXAMPLE 2

Fresh sides of salmon with skin were salted as in example 1.

Following rinsing and dripping off, the sides of salmon were then placed in a basket that was immersed in an ultrasound vat filled with rapeseed oil, with a smoke extract added according to EP 1,296,569.

Following completion of ultrasound treatment, the sides of salmon were placed on a skinning machine known per se for removal of the skin side. The sides of salmon were then placed on a conveyor that transported the fish through a microwave oven of the pass-through type in a continuous movement.

At the exit side of the oven and the sides of salmon were removed manually from the conveyor, put in crates and driven to cold storage.

Also, by this process a product corresponding to fresh-smoked salmon (i.e. cold-smoked) was achieved.

EXAMPLE 3

Fresh sides of salmon with skin were placed on a conveyor that transported the fish through an ultrasound vat filled with a saline brine, in which the fish was treated with ultrasound for a few minutes. After a distance corresponding to sufficient dripping off of the fish the conveyor continued through an ultrasound vat filled with rapeseed oil, which had a smoke extract according to EP 1,296,569 added.

The rest of the process proceeded as in example 2.

Also, by this process a product corresponding to fresh-smoked salmon (i.e. cold-smoked) was achieved.

EXAMPLE 4

Fresh "butterfly fillets" of trout with skin were placed with the skin side facing upwards on a table covered with salt, whereby the salt ad- hered to the meat side. The fillets were placed on a grill on a frame with the skin side facing downwards and were allowed to remain for a period of time of between 1 and 6 hours, depending on the desired degree of salting.

Then the salt was rinsed off with water and the trout fillets were

placed in cold storage for a time to level out and drip off and for excess water to evaporate.

The trout fillets were placed in a basket that was immersed in an ultrasound vat filled with rapeseed oil, with a smoke extract according to EP 1,296,569 added.

Then the fillets dripped off and were treated with microwaves as in example 1, the ultrasound treatment though being continued to reach a temperature in the fillets of about 60 °C, the treatment time being dependent on the size of the fillets. No smoking coating of any form could be detected on the fillets.

The skin was removed from fillets manually while these were warm, and they were put in crates or on frames and driven to cold storage.

A product corresponding to smoked trout (i.e. heat-smoked) was achieved.

EXAMPLE 5

Fresh "butterfly fillets" of trout were salted as in example 4.

After rinsing and dripping off, the fish was moved from the grill to a combined smoking and microwave oven, where the fish was exposed to smoke during simultaneous treatment with microwaves. A considerably shorter treatment time was used than with conventional smoking.

Subsequently, only an insignificant weight loss of the fish compared to the weight loss with conventional heat-smoking, as well as it not being possible to detect any form of smoking coating.

The skin was removed from the fillets manually while these were warm and they were placed in crates or on frames and driven to cold storage.

EXAMPLE 6

Fresh "butterfly fillets" of trout were salted by ultrasound treatment in the same way as the sides of salmon in example 3.

Then the fillets were allowed to drip off and were treated with microwaves in the same way as the sides of salmon in example 3, the

treatment with microwaves though being continued to reach a temperature in the fillets of about 60 ⁰ C, the treatment time being dependent on the size of the fillets.

Subsequently, only an insignificant weight loss compared to the weight loss with conventional smoking was detected, as well as it not being possible to detect any kind of smoking coating.

The skin was removed from the fillets manually while these were warm, and they were put in crates or on frames and driven to cold storage. A product corresponding to smoked trout (i.e. heat-smoked) was achieved.