DESCRIPTION

Technical field

The present invention is generally applicable to the field of the food products and particulary relates to a plant for decontaminating cured food products.

The invention also relates to a method for decontaminating cured food products using the above plant.

Background Art

As is known, some food products, under certain storage conditions, may be prone to contamination by parasites or other microbial species and require surface treatment involving decontamination or disinfection prior to marketing.

This problem is particularly severe for certain types of meat products, such as hams, bacon, and suchlike, or even cheese, in particular those such as parmesan, which, if not properly treated and stored, may be infested with different types of parasites.

For example, hams and particularly low-salted Spanish hams, whose curing and storage usually occurs in natural environment and at room temperature, are often subjected to be infested by colonies of mites proliferating in both the fat and lean areas, rendering the product marketable only after proper disinfection.

Generally, the colonies of mites proliferate in external areas of the ham's surface but when they penetrate inside, reaching areas in the vicinity of the bone, their action is particularly damaging.

Normally, these products are subjected to a boiling oil treatment designed to eliminate any colonies of parasites and to create unsuitable conditions for the development of the same.

Nevertheless, the oil bath, in addition to the degrading of the organoleptic properties of the product, sets forth obvious drawbacks due to the high energy required to keep the oil at the necessary temperature. Other known solutions envisage thermal treatment of the products within conditioning chambers, essentially ovens, in which the products remain for a predetermined time at a temperature above room temperature.

US39061 15 discloses a method for the treatment of meat products which comprises a step involving pre-treating the products by means of a pre-cooking step.

The pre-treatment envisages, in particular, a first pre-heating with steam, in which the product is brought up to a temperature above 70 °C, followed by a second pre-heating with hot air at temperature of between 60 °C and 200 °C, for a time of 200 s.

Subsequently, the product is subjected to irradiation with microwaves in order to noticeably raise the temperature and complete the cooking thereof.

It is apparent that this method is suitable for the treatment of products that must be eaten cooked, such as bacon, while it cannot be applied for the treatment of cured products which are eaten uncooked, for which it is necessary to maintain the organoleptic characteristics as much as possible.

ES2186539 discloses a plant for the disinfection of meat products by means of an air flow heated to a temperature of between 50 °C and 100 °C.

The products are kept inside a conditioning chamber by means of a grill, for a period of time ranging from 5 to 10 minutes.

Nevertheless, this combination of treatment temperature and time has not proved to be completely effective in removing the parasites in their totality.

Energy consumption is also relatively high due to the need to continuously supply conveyors with hot air suitable to produce a flow inside a conditioning chamber with a predetermined volume.

Not least, the particular arrangement of the products on the grill does not guarantee that the said products are hit by the flow of hot air in a uniform and complete manner.

US6039991 discloses a method for sanitising food products, in particular ground meat, which provides treatment with microwaves and hot air.

More particularly, the product is heated quickly and thoroughly by irradiation with an electromagnetic field having a microwave- range frequency which brings the product up to a temperature of between 45 °C and 48 °C, while the hot air, delivered at 72 °C and under a high pressure above 4 bar, performs a surface sanitation. Finally, the product is stabilised by means of cooling.

However, even this method, while allowing stabilisation of the organoleptic characteristics of the treated product, is only suitable for products to be eaten cooked and does not allow the removal of any parasites present on the surface zones. Furthermore, it requires an expensive shielding of the antenna generating the microwaves.

Disclosure of the invention

A main object of the present invention is to overcome the drawbacks of the above mentioned prior art by providing a plant for decontaminating cured food products which is particularly efficient and cost effective.

A particular object of the invention is to provide a plant for decontaminating cured food products which allows to remove any colonies of parasites present in the product in an essentially complete manner with relatively reduced removal times.

A further object of the present invention is to provide a plant for decontaminating cured food products which allows the essentially complete removal of any parasites colonies present in the product without altering the organoleptic characteristics thereof.

A further object of the present invention is to provide a plant for decontaminating food products which features high productivity.

A further and not last object of the present invention is to provide a method for decontaminating cured food products which is particularly quick and efficient and allows to preserve the organoleptic properties of the products.

These objects, as well as others that will appear more clearly hereinafter are achieved by a plant for decontaminating cured food products, comprising a treatment chamber having an inlet port for the products to be treated and an outlet port for the treated products, said treatment chamber at least partially enclosing internally thereof irradiating means for generating an electromagnetic field for irradiating the products present in said chamber and heating them up to a first predetermined temperature, surface treatment means for treating the products with hot air at a second predetermined temperature.

The plant is characterised in that said first heating temperature is lower than the cooking temperature for the products to be treated and that the said surface treatment means comprise a hot air generator designed to generate a high-speed hot air jet directed onto the surface of the products for removing both mechanically and thermally parasites nested in the surface layer thereof.

Thanks to this combination of features , the plant allows disinfection of the food products within a particularly short period of time and in an effective manner, but without affecting the organoleptic properties of the treated products.

Suitably, the plant may comprise heating means designed to bring the said hot air flow up to a temperature of between 300 °C and 700 °C, preferably between 400 °C and 500 °C.

Moreover, the slot may have a width of between 0,5 cm and 3 cm, preferably close to 1 ,5 cm, in order to have a flow rate of between 40 m/s and 150 m/s, preferably between 50 m/s and 130 m/s.

Thus, the hot air flow will have a high level of kinetic energy sufficient to remove any parasites present on the surface of the product.

Advantageously, the electromagnetic field may have a frequency selected in the range of the radio frequencies for industrial use, preferably between 6 MHz and 500 MHz and even more preferably between 20 MHz and 50 MHz, in order to heat the product to a first temperature of between 30 °C and 70 °C, preferably between 45 °C and 50 °C.

Unlike typical microwaves frequencies, comprised between 3 GHz and 300 GHz, use of frequencies within the ranges mentioned above allows the product to be heated thoroughly but without resulting in the cooking or pre- cooking thereof.

It has been experimentally observed, in fact, that the heating of the products greatly enhances the sanitation and decontamination effect of the high-speed air jet with respect to use of the hot air flow alone.

In particular, the use of frequencies in the radiofrequency range for industrial use enables to act upon the part of the products with the highest water content, i.e. the particularly lean surface part, where colonies of parasites such as mites generally nest.

Accordingly, the RF field, as well as performing, in itself, a preliminary parasite elimination action (although not sufficient to guarantee complete disinfection of the product), also facilitates the colonies' emergence towards the exterior, allowing the air flow to act more effectively.

Advantageously, the plant may include means for pre-treatment with steam located upstream of the said heating means and designed to supply superheated steam having a third temperature of between 100 °C and 200 °C, preferably 180 °C, into said chamber.

In this way, it will be possible to obtain better humidification of the products, in particular inside their micropores where it is more likely for particles of dirt and damaging residues to accumulate, thereby improving the effectiveness of the radio frequency electromagnetic field that - as is known - only acts upon the aqueous part of the product.

Suitably, the chamber may house movement means designed to promote the continuous advancement of the products to be treated therethrough with a feeding speed comprised between 0,5 m/min and 1 ,5 m/min, preferably between 0,7 m/min and 1 ,2 m/min.

Moreover, the chamber may be scaled to hold the products inside it for a predetermined maximum time of between 50 s and 120 s, preferably close to 60 s.

This will prevent the products staying within the electromagnetic field for too long or in contact with the hot air flow for too long, preventing overheating which could result in partial cooking that would affect the organoleptic characteristics.

In a further aspect of the invention, a method for decontaminating cured food products is provided in accordance with claim 12.

Advantageous embodiments of the invention can be obtained in accordance with the dependent claims.

Brief description of the drawings

Further features and advantages of the invention will emerge in light of the detailed description of a preferred but not exclusive embodiment, provided in the form of a non-limiting example, with the help of the accompanying drawings, in which:

Fig. 1 is a perspective view of the plant according to the invention; FIG. 2 is a top-down sectional view of the plant in Fig. 1 ;

FIG. 3 is a frontal view of a detail of the plant in Fig. 1 illustrating the means of surface treatment in a first preferred embodiment;

FIG. 4 is a frontal view of a the plant in Fig. 1 sectioned along plane line IV-IV;

Fig. 5 is a perspective view of a detail of a plant according to the invention illustrating the means of surface treatment in a second preferred embodiment;

FIG. 6 is a perspective view of a portion of the detail in Fig. 5;

FIG. 7 is a frontal view of a the plant in Fig. 1 sectioned along plane line VII-VII.

Detailed description of a preferred embodiment With reference to the above figures, a plant for decontaminating cured food products overall identified with 1 can be used for the decontamination treatment of cured meat products P, such as ham, bacon, or similar food products, or any further products subjected to aging, such as some types of cheese, in particular such as grana parmigiano..

The decontamination treatment to which the products P will be subjected allows the elimination of any colonies of parasites, especially mites, which may be present on the surface or on the most external layers of the products. As shown in Fig. 1 , plant 1 comprises a processing chamber 2, which may be of the tunnel type, with an inlet port 3 for the products to be treated P, and an outlet port 4 for the treated products P ₀ , arranged in the advancement direction.

The chamber 2 houses internally thereof, at least partially, both irradiation means 5 designed to generate a radio frequency electromagnetic field to irradiate the products P and means of surface treatment 6 of the products, arranged downstream of the irradiation means 5 with respect to the advancement direction imparted to the products P within the chamber 2.

In particular, the irradiation means 5 are designed to generate an electromagnetic field to direct against the products P to be treated present in the chamber 2 in order to bring them up to a first predetermined temperature T-i , which will be appropriately lower than the cooking temperature Tc for the products P.

The surface treatment means 6 are of the hot air type, so as to direct a flow of hot air having a second predetermined temperature T ₂ onto the surface of the preheated product P.

According to a peculiar feature of the invention, the surface treatment means 6 may include a hot air generator 7 having at least one conveying conduit 8 for the hot air flow.

The conveying duct 8 will be provided with an outlet slot 9 designed to accelerate the flow of outgoing air and direct it at high speed onto the surface of the product P in order to facilitate the removal of parasites by mechanical and thermal action.

The hot air generator 7 may comprise heating means, not shown in the figures, designed to bring the said hot air flow up to a second temperature T ₂ of between 300 °C and 700 °C, preferably between 400 °C and 500 °C.

The heating means may be of any type, for example of electrical type, with no limitation of the scope of the invention.

The hot air generator 7 may also comprise a low-speed, high-flow rate blower 10 connected to the conveying conduit 8 for generating an outlet flow having an outlet speed v _e comprised between 40 m/s and 150 m/s, preferably between 50 m/s and 130 m/s.

For example, the blower 10 of the generator 7 can be dimensioned to produce an outflow at the slot 9 having a rate Q of between 1500 litres/min and 3500 litres/min, with significantly low fluid pressure, e.g. between 0 and 270 millibars.

Such values of the outflow speed v _e combined with the temperature T ₂ of the flow produced by the treatment means 6 will allow a rapid and effective reduction of the colonies of parasites, since the sanitising action of the temperature will be combined with the physical removal action of the high-speed flow.

Moreover, the action of the hot air flow will dry the product P in the event that it is pre-treated with water, steam, or similar means as will appear more clearly hereinafter, thereby improving the conditions for the subsequent storage of the same.

As shown in Fig. 2, the conveying conduit 8 will be essentially tubular and provided at its inside the chamber 2 with an outlet 11 having a tapered section, in which the slot 9 is formed.

As more clearly shown in Fig. 3, the slot 9 will have a width w of between 0,5 cm and 3 cm, preferably close to 1 ,5 cm.

The slot 9 may be dimensioned in height according to the type of products P to be treated and the size thereof, without this parameter particularly conditioning the characteristics of the outflow.

For example, in case that the plant 1 is designed for treating hams or the like products , the height h of the slot 9 may be between 200 mm and 400 mm, preferably close to 300 mm.

Preferably, as shown in Figs. 2 and 4, the surface treatment means 6 may include two separate and similar units each having a blower 10 connected to a conveying conduit 8 provided with an outlet slot 9 for a respective high-speed flow.

The two units may be arranged in such a manner that the respective slots 9 are positioned symmetrically with respect to a plane of symmetry π essentially parallel to the products' advancement direction X.

The slots 9 may be arranged in mutually opposed and facing positions and will be suitably spaced apart along a transverse direction Y, which is essentially horizontal, so as to determine a working area A through which the products P to be treated will pass.

Accordingly, each slot 9 will direct a respective hot air jet in an essentially transverse direction so as to impinge the external surface of the product P.

Figs. 5 and 6 show an alternative configuration of the surface treatment means comprising a conveying chamber 12 shaped to surround, at least partially a product P to be treated and having an internal side wall 13 with an essentially longitudinal plane of symmetry ττ' and defining a central passageway 14 for the products P.

The conveying chamber 12 will include a pair of conveying conduits 15, 16 defined by respective essentially vertical C-shaped tubular elements, arranged on opposite sides with respect to the plane of symmetry ττ' and having corresponding side walls 13 arranged in a mutually facing relationship so as to define the passageway 14.

Suitably, the pair of shaped tubular elements 15, 16 may feature, as a whole, an essentially annular shape with an interruption in the upper part thereof to allow the passage of supports or hooks 17 for the products P to be treated.

Each side wall 13 will be provided with a respective slot 18 having essentially similar dimensions to those stated above and arranged in a mutually opposing relationship so as to direct hot air jets, in a uniform manner, onto essentially the entire external surface of the products P to be treated.

The passageway 14 will have dimensions comparable to the average dimensions of the products P to be treated, so that their external surface is sufficiently close to the slots 18 and the action of the hot air flow is particularly efficient.

Each tubular element 15, 16 may be fluidly connected, at the lower portion thereof, to the blower 10 on the hot air generator 7.

The slots 18 may be made in the corresponding C-shaped upper portions of the tubular elements 15, 16.

Preferably, the height h of the slots 18, measured along the longitudinal extension of the corresponding shaped tubular element 15, 16, may be between 200 mm and 400 mm, preferably close to 300 mm.

The width w measured along the longitudinal direction X, will preferably range between 0,5 cm and 3cm, still more preferably close to 1 ,5 cm.

As shown in Fig. 1 , the processing chamber 2 may feature a first portion 19 housing the irradiation means 5 and a second portion 20 located downstream of the first 19 and housing the surface treatment means 6, or a part of the same, in particular the terminal sections of the conveying conduits 8 equipped with the tapered outlets 11.

The first portion 19 and the second portion 20 of the chamber 2 will define, respectively, a first predetermined advancement direction L and a second predetermined advancement direction X for the products P internally thereof.

It is apparent that the shape of the chamber 2 shown in the figure is purely illustrative, since the arrangement of the different operating means may vary depending on the dimensions and the space available within the premises in which the plant 1 has to be located.

In particular, the irradiation means 5 may be arranged in the same portion of the chamber 2 in which the means of surface treatment 6 are housed, upstream of the hot air generator 7.

The irradiation means 5 may be of the type described in the Italian patent n. 1363438 and, as shown schematically in Fig. 7, may include a generator 21 for generating a radio frequency electromagnetic field with an applicator 22 having at least one pair of electrodes 23 designed to generate and direct the field over a working area B, and a voltage generator 24 to whose poles the electrodes 23 will be connected.

The electrodes 23 will be arranged on opposite sides with respect to the first advancement direction L so as to determine a first working area B through which the products P will pass and into which the electromagnetic field will be directed.

The irradiation means 5 will be designed to heat the food product P to a first operating temperature T _{1 ;} which is lower than the second temperature T ₂ .

Preferably, the electromagnetic field generating device 21 may be designed to generate a field having a frequency in the range of radio frequencies for industrial use, for example between 6 MHz and 500 MHz, preferably between 20 MHz and 50 MHz, with enough power to heat the surface of the product P to a first temperature T-i of between 30 °C and 70 °C, preferably between 45 °C and 50 °C.

In particular, the frequencies used can be selected from within the frequency ranges permitted by international standards for civil or industrial uses, whose central values are 6,78 - 13,56 - 27,12 - 40,68 - 433,92 MHz

It has been experimentally observed that the electromagnetic field generating device 21 already works in a optimised manner at lower frequency values, for example, around 27,12 MHz or 40,68 MHz.

The electrodes 23, which - naturally - must be made of a conductive material, such as copper, aluminium or similar material may be substantially flat and arranged in mutually facing positions or constituted by annular elements inside which the products P to be treated pass, e.g. of the type described in patent n. EP1912512 in the name of the same applicant.

Upstream of the irradiation means 5, there may also be means 25 for steam pre-treating the products P, housed in a third portion 26 of the chamber 2 which is provided with an inlet 3 and determines a third longitudinal feeding direction Z.

The means of pre-treatment (25) will comprise one or more nozzles - not shown in the annexed figures - designed to introduce superheated steam into the third portion 26 of the chamber 2, the said steam having a third temperature T ₃ comprised between 100°C and 200 °C, preferably close to 180°C. The third portion 26 of the chamber 2 may be connected with the first portion 19, or at least partially isolated by at least partially mobile dividers designed to allow the passage of the products P, but limiting the passage of steam to the first portion 19.

Moreover, the third portion 26 of the chamber 2 may have one or more drain channels 27 which may be selectively opened to allow discharge of the steam.

The chamber 2 will house movement means 28 designed to promote the continuous feeding of the products P to be treated through the separate portions 19, 20, 26 of the chamber 2, in the respective advancement directions Z, L, X, through both the field electromagnetic and the high-speed hot air flow.

The movement means 28 will be designed to promote the continuous, controlled advancement of the products P to be treated with an advancement speed v _a comprised between 0,5 m/min and 1 ,5 m/min, preferably between

0,7 m/min and 1 ,2 m/min.

Moreover, the chamber 2 will be dimensioned to hold the products internally thereof for a predetermined maximum time t _ma x of between 50 s and 120 s, preferably close to 60 s.

These particularly high feeding speeds v _a will prevent the products P being subjected to the action of the hot air flow for too long, which could degrade the organoleptic properties.

By way of example, the movement means 28 may include an essentially longitudinal guide track 29, which crosses the treating chamber 2 from the inlet port 3 and outlet port 4 thereof, which is provided with a plurality of supports or hooks 17 for suspending the respective products P.

In one configuration, not illustrated herein, the movement means may be configured to impart a rotational movement to the product P around an essentially longitudinal axis.

A method for the biological treatment of food products according to the invention can be obtained, preferably but not exclusively, with the plant 1 described above essentially comprises an initial step of providing of a treatment chamber 2 with an inlet port 3 and an outlet port 4, a step of continuously and controllably moving the product P inside the treating chamber 2 between the inlet port 3 and outlet port 4, a step of irradiating the product P with electromagnetic waves having a predetermined frequency, so as to bring them up to a first predetermined temperature T-i, and a subsequent step providing a surface treatment of the products P, which are heated by generating and conveying a hot air flow having a second predetermined temperature T ₂ .

Preferably, the heating and surface treatment steps will be performed at the same time of the continuous movement step, i.e. with the products subjected to continuous and controlled movement.

The surface treatment step comprises a step of generating a hot air flow and subsequent accelerating of the same flow directed, at high outflow speed v _e , onto the surface of the product in order to remove the parasites nesting in the surface layers thereof by means of both mechanical and thermal action.

All the operating parameters relating to the various steps in the method can coincide with those indicated above for the plant.

The electromagnetic field frequency will be chosen from the range of values of radio frequencies for industrial use, and will preferably be comprised between 6 MHz and 500 MHz and even more preferably between 20 MHz and 50 MHz.

Upstream of the radio frequency irradiating step, there may be provided a step envisaged involving pre-treatment and humidifying of the products, in particular with superheated steam having a temperature close to 180 °C.

The pre-treatment, heating and surface treatment steps will preferably be performed with the products moved at a continuous predetermined advancement speed v _a designed to perform a treatment cycle within a predetermined maximum time t _ma x of between 509 s and 120 s, preferably close to 60 s.

The method according to the invention may be preceded and/or followed by further steps envisaging the conditioning of the product, not described herein, according to the type of product P to be treated or the features to be imparted thereto, in a manner which implies no limitation to the scope of the present invention.

From the foregoing, it is apparent that the invention achieves the intended objects, in particular of providing a plant and a method for decontaminating cured food products that allows disinfection of the products to be treated in a rapid and essentially complete manner, while preserving the organoleptic characteristics thereof.

The above plant and method are susceptible of numerous modifications and changes all falling within the scope of the invention as defined in the attached claims. All the details may be replaced by other technically equivalent elements, and the materials may differ according to the requirements without falling outside the scope of the invention.

Even though the plant and the method have been described with particular reference to the annexed figures, the reference numbers have been used to improve comprehension of the invention and do not limit the scope of protection claimed herein.