DEVICE FOR THE INSPECTION AND FOR THE SELECTION OF FOOD PRODUCTS CONTAMINATED BY AFLATOXINS

DESCRIPTION

The present invention concerns an apparatus for the inspection and selection of food products potentially contaminated by aflatoxins, in particular solid bulk foods such as cereals, pulses and dried fruit, more specifically pistachios.

The present invention also concerns a system for the treatment of these food products contaminated by aflatoxins, equipped with the aforesaid inspection and selection apparatus.

As is known, aflatoxins are produced by the metabolism of some fungal strains of Aspergillus flavus and Aspergillus parasiticus, which develop in numerous plants such as cereals, oilseeds (for example peanuts), spices, grains, dried fruit and nuts, both during harvesting and during storage.

Among the aflatoxins known to date, only some are considered important both for diffusion and for toxicity, namely the aflatoxins Bl, B2, Gl, G2 and Ml. Among these, the most toxic aflatoxin is the aflatoxin Bl, which is commonly considered genotoxic and hepatocarcinogenic.

The effects on the human body caused by the consumption (or assimilation) of non- negligible doses of aflatoxins, in particular of the aflatoxin Bl, are well known, and include immune system disorders, liver problems, and in some cases, even death.

For these reasons, European law, in particular EU regulation 165/2010, establishes the maximum levels of aflatoxins tolerable in food products such as cereals, dried fruit and milk.

Among the products subject to contamination by the aflatoxin Bl pistachios are those that have the highest level of risk. Specifically, although the incidence of contamination in these products is relatively low, a single fruit can carry a very large amount of aflatoxins, at times tens of orders of magnitude higher than the level established by law per kilogram of product.

Normally, sample checks are carried out on these products. However, due to the low incidence of contamination by aflatoxins, the conventional control system does not guarantee sufficient safety for consumers of these foods or of processed food products that contain pistachios.

In this context, the object of the present invention is to propose an apparatus for the inspection and selection of food products contaminated by aflatoxins, which overcomes the aforesaid problems of the prior art.

In particular, an object of the present invention is to produce an apparatus capable of inspecting solid bulk food products, such as dried fruit or cereals, of identifying potentially contaminated products and of separating them from the uncontaminated products, hereinafter also indicated as “good” products.

A further object of the present invention is to provide an in-line apparatus capable of processing high volumes of product and, therefore, of allowing a company to carry out non-destructive inspection of all product batches to be placed on the market or to be used as ingredients to prepare recipes or semi-finished products.

Another object of the present invention is to produce an apparatus capable of identifying products contaminated by aflatoxins with high precision, in particular of distinguishing products effectively contaminated from so-called “false positive” products, i.e., those carrying on the surface substances that are fluorescent in a wavelength comparable with that of the aflatoxins, such as kojic acid, the metabolite of the fungus that produces aflatoxin, which, per se, is not toxic.

Yet another object of the present invention is to produce an in-line system for treating food products contaminated, or potentially contaminated, by aflatoxins and reintroducing them into the production cycle. These objects are achieved by an apparatus for the inspection and selection of food products contaminated by aflatoxins, in particular cereals and dried fruit, in conformity with claim 1.

In particular, according to the invention, the apparatus comprises at least:

- a conveyor line;

- a first inspection station; and

- a first selection unit.

The conveyor line is configured to transfer the food products between an inlet of the apparatus and at least one outlet of the apparatus; said conveyor line has a supporting surface suitable to receive the solid bulk food products distributed in a uniform layer.

The first inspection station is configured to inspect a flow of food products in movement carried by the conveyor line. According to the invention, said first inspection station comprises: a first housing positioned above the supporting surface of the conveyor line; at least one ultraviolet light source, mounted in the first housing so as to direct a beam of ultraviolet light toward the food products on the supporting surface; an RGB video camera mounted in the first housing and oriented toward the area of the supporting surface illuminated by the ultraviolet source; a first control unit connected at least to the RGB video camera.

According to the invention, said control unit is configured to receive and analyse the images filmed by the video camera, in particular to identify in the layer of food products in movement on the conveyor line those with photoemissions (so-called induced fluorescence) that indicate the presence of aflatoxins, i.e., that are potentially contaminated.

The first selection unit, located downstream of the first inspection unit, is controlled by the first control unit and is configured to separate the good food products from those that are potentially contaminated and to eject the former toward a collection point.

Therefore, with the apparatus according to the present invention it is possible to accurately inspect large amounts of food products in real time and to identify the single contaminated products and separate them from the good products in an automated manner.

According to an aspect of the invention, the first inspection unit comprises a pair of ultraviolet light sources arranged in the housing facing each other, relative to the direction of movement of the conveyor line, and oriented so that the light beam of each is directed inclined relative to the supporting surface of the conveyor line with an angle between 35° and 55° (or 125° and 145° considering the complementary angle). In this way, it is possible expose the surface of the food products to the ultraviolet light source in a uniform and complete manner, eliminating or minimising the “grey area”.

The RGB video camera is mounted in the housing preferably in a central position between the two ultraviolet light sources, and is preferably oriented substantially normal to the supporting surface of the conveyor line.

According to another aspect of the invention, the at least one ultraviolet light source is configured to emit light with a wavelength of 365 nm. This wavelength is particularly effective for stimulating the fluorescence of the aflatoxin and therefore facilitates its identification by an algorithm implemented in the control unit.

According to another aspect of the invention, the apparatus can also comprise a second inspection unit, placed downstream of the first selection unit along the conveyor line, suitable to inspect the flow of potentially contaminated food products identified by the first inspection unit.

According to the invention, the second inspection unit comprises:

- a second housing positioned above the supporting surface of the conveyor line;

- at least one ultraviolet light source, mounted in the second housing so as to direct a beam of ultraviolet light toward the product on the supporting surface; at least one hyperspectral video camera, mounted in the second housing and oriented toward the area of the supporting surface illuminated by the ultraviolet source;

- a second control unit connected at least to the hyperspectral video camera.

The second control unit is configured to receive the images filmed by the at least one hyperspectral video camera and to analyse said images, in particular to distinguish, based on the spectrum of the photoemissions of said products, those probably contaminated by aflatoxins from the good products.

According to this variant, the apparatus further comprises a second selection unit, downstream of the second inspection unit, controlled by the second control unit and configured to separate the uncontaminated food products from those probably contaminated and to eject the former toward a collection point.

According to an aspect of the invention, the second inspection unit can comprise two or more hyperspectral video cameras.

According to this variant, each video camera is set to detect a specific wavelength or a predefined range of wavelengths.

According to a preferred embodiment, a first video camera is set to detect photoemissions with wavelengths between 430 nm and 450 nm, a second video camera is set to detect photoemissions with wavelengths between 480 nm and 500 nm, and a third video camera is set to detect photoemissions with wavelengths between 520 nm and 540 nm.

This configuration allows effectively contaminated products, in which photoemissions are between 430 nm and 450 nm, to be distinguished from false positives due to the presence of kojic acid, with photoemissions between 480 nm and 500 nm or natural photoemissions of the pistachio between 520 nm and 540 nm.

The video cameras are configured to operate in parallel and each of them can be associated with second independent control units, or with a single control unit.

The various control units of the apparatus can be implemented and managed from a control station of the apparatus.

This control station is typically equipped with viewing interfaces (screens, displays, etc.) and input interfaces (keyboards, touch screen displays or similar). According to a preferred variant, the video camera of the first inspection unit and each of the hyperspectral video cameras of the second inspection unit are connected to a viewing interface that allows viewing of the images filmed or other operating parameters such as graphics or similar.

According to a preferred embodiment, the second inspection unit comprises at least one ultraviolet light source arranged in the housing above the belt and oriented so that the light beam is substantially orthogonal to the supporting surface. The hyperspectral video cameras are preferably arranged so that the observation point is perpendicular to the supporting surface.

Also in this case, the ultraviolet light source is configured to emit light with a wavelength of 365 nm.

The aforesaid objects are also achieved with a system for treating food products, in particular cereals and dried fruit, contaminated by aflatoxins.

According to the invention, the system comprises an inspection and selection apparatus according to one of the variants described above, which delivers at the outlet a flow of food products potentially or probably contaminated distributed in a uniform layer on the conveyor line.

In detail, this flow of potentially or probably contaminated products comes from the first selection unit, where it is the only one present in the apparatus, or from the second selection unit, which has further treated the separated flow of food products delivered from the first selection unit. According to the invention, the system comprises at least one first treatment unit to eliminate or reduce the aflatoxins present in the food products. Said first treatment unit is typically positioned above the conveyor line, downstream of the inspection and selection apparatus, and comprises one or more ultraviolet light sources in the UV-C band, i.e., with a wavelength between 100 nm and 280 nm, oriented to direct at least a part of the light beam onto the layer of food products.

According to a preferred embodiment, the UV-C ultraviolet light sources comprise tube lamps arranged with their axis extending substantially parallel to the direction of movement of the food products on the conveyor line.

The number of lamps and their length depends on various factors, such as the extension in width of the supporting surface of the products and the average speed at which they are conveyed on the conveyor line.

To maximise the efficacy in destroying aflatoxins, the UV-C ultraviolet light sources are placed at a distance from the supporting surface preferably between 15 mm and 50 mm. For this purpose, the apparatus comprises a device, preferably placed downstream of the first inspection unit, that distributes the products in a uniform layer preventing areas of accumulation. This operation also allows better viewing of the products in the inspection unit.

According to another aspect of the invention, the system can comprise a second treatment unit, downstream of the first treatment unit, which comprises a plurality of ozonator devices, positioned along the conveyor line, suitable to generate a flow of ozone directed toward the layer of food products.

Said ozonator devices are preferably positioned in a containment chamber in the form of a tunnel placed above the conveyor line and in direct communication with the food products. Said chamber is also in communication with a suction device configured to draw in the excess gas and prevent it from dispersing outside the unit. The action of these ozonator devices allows an increase in the efficacy in destroying aflatoxins, especially in foods such as pistachios, the partially open shell of which can obstruct (shield) the action of the ultraviolet radiation. On the contrary, the gases produced by the ozonator devices can surround the products completely, even reaching the interstices between the surface of the nut and the shell.

The positions of the first treatment unit and of the second treatment unit can also be inverted relative to the direction of flow of products; the second treatment unit can be directly downstream of the inspection apparatus.

According to another aspect of the invention, the second treatment unit can comprise an ionising radiation emitting device oriented toward the flow of food products to be treated. This device allows the destruction of aflatoxins, and other pathogenic species, also under the surface of the food product, guaranteeing an effective sanitising action also for products in which the outer shell is only slightly open.

More in detail, according to this variant, said second treatment unit comprises an X- ray tube that generates radiation in the X-ray spectrum. The power used by the X-ray tube is preferably greater than 500 W and more preferably greater than 700 W, while the voltage is at least 30,000 V, preferably at least 50,000, typically up to 90,000 V.

According to another aspect of the invention, the system can comprise at least one video camera configured to film the flow of food products entering the treatment unit, i.e., downstream of the selection devices. According to this variant, at least one of the control units for controlling the treatment unit is connected to said video camera and is configured to control one or more of said treatment units in real time as a function of the amount of food product present on the conveyor line.

In particular, thanks to this system for controlling the flow of contaminated products in real time, it is possible to selectively exclude the treatment units or sub-parts thereof (for example, only some of the UV-C lamps or some of the ozonator devices) or in any case to modify its action, for example by varying the power supplied.

This video camera is preferably arranged immediately upstream of the first treatment unit after the inspection block, or directly inside one of said units.

Further features and advantages of the present invention will be more apparent from the description of a preferred, but not exclusive, example of embodiment of a system for the treatment of food products, as illustrated in the accompanying figures, wherein:

- Fig. 1 is a side view of the system for the treatment of the food products according to the present invention;

- Fig. 2 is a perspective view of the first inspection unit partially disassembled;

- Fig. 3 is a perspective view of the second inspection unit partially disassembled;

- Fig. 4 is a perspective view of the selection unit;

- Fig. 5 is a perspective view of the first treatment unit partially disassembled;

- Fig. 6 is a side view of the second treatment unit partially disassembled;

- Fig. 7 is a perspective view of the third treatment unit partially disassembled.

With reference to Fig. 1, there is illustrated as a whole a system 100 for the inspection and treatment, in particular for the sanitisation, of food products contaminated by aflatoxins.

The system 100 comprises a feed unit 10, an inspection apparatus 200 and a treatment block 300.

The inspection apparatus 200 comprises a first inspection unit 20, a first selection unit 30, a second inspection unit 40 and a second selection unit 50.

The treatment block 300 comprises a first treatment unit 60, a second treatment unit 70 and a third treatment unit 80.

Each unit of the system 100 is configured to convey the food products between an inlet 101 and an outlet 102 of the system 100.

Therefore, each unit includes a portion of the conveyor line of the food products, indicated in the figure with the number 90. The conveyor line comprises a supporting surface 91 on which the products are distributed. The conveyor line 90 is essentially formed by belts and optionally by conveyors, chutes or other similar elements.

The feed unit 10 comprises a vibrating screen 11 suitable to distribute the products uniformly on the conveying surface. Said feed unit preferably also comprises a “levelling” system suitable to spread out any accumulations of products into a single uniform layer.

With particular reference to Fig. 2, the first inspection unit 20 of the inspection block 200 comprises a supporting structure 21 positioned above a belt 22 belonging to the conveyor line 90.

Said supporting structure 21 acts as housing for a pair of UV-C lamps 23a, 23b arranged facing each other and for an RGB video camera 24.

The lamps 23a, 23b are arranged so that the light beam is inclined relative to the supporting surface 91 on the belt 22, in particular by an angle a of around 45° for the lamp 23a and by an angle P of around 135° for the lamp 23b, considering the same absolute reference.

The RGB video camera 24 is preferably positioned at the centre of and equidistant from the two lamps 23a, 23b and is oriented substantially perpendicularly to the supporting surface 91.

The+ supporting structure 21 is delimited by walls made of opaque material, not represented in the figures, which prevent exposure of the products to ambient light, which would alter the results of the UV light inspection.

The first inspection unit 20 is associated with a first control station 25 which integrates a control unit dedicated to controlling the lamps 23a, 23b, the video camera 24 and optionally the belt 22. The control unit 25 is preferably equipped with an input/output interface 26, typically a touch screen display, which allows the images filmed by the video camera 24 and/or other information to be viewed and commands to be given to the unit. A first selection unit 30 connected to the control unit of said first inspection unit 20 is arranged immediately downstream of the first inspection unit 20.

With reference to Fig. 4, the first selection unit 30 comprises a movable channel 31 arranged at the outlet of the belt 22 of the first inspection unit 20 and aligned with said belt 22 in the direction of flow of the food products. Said movable channel 31 has a bottom surface 31a that can receive the flow of food products in movement. The movable channel 31 is, in fact, movable between a first position in which the bottom surface 31a is facing the direction of movement of the flow of products, and a second position in which it is turned in the opposite direction.

In the first position, the movable channel 31 allows the food products to pass from the belt 22 of the first inspection unit 20 to a subsequent station, specifically to the second inspection unit 40, along the conveyor line, as illustrated in Figs. 1 and 4. Instead, in the second position the movable channel 31 acts as diverter to divert the flow of products downward where it is collected from an outlet channel 32.

The movable channel 31 is connected to actuator means, not illustrated in the figure, controlled by the control unit of the first inspection unit 20.

When no contaminated products are detected on the conveyor line, the movable channel remains in the second position and the flow of good products is diverted into the outlet channel 32 toward a collection point.

When the first inspection unit 20 detects potentially contaminated products, the movable channel 31 is moved for a certain interval of time into the first position so as to carry said potentially contaminated products and a certain amount of products in the vicinity toward the second inspection unit 40.

The control station 25 of the first selection unit 20, or rather the control unit comprised therein, is preferably configured also to control said first selection unit 30.

With reference to Fig. 3, the second inspection unit 40, just as the first, comprises a supporting structure 41 positioned above a belt 42 belonging to the conveyor line 90.

The supporting structure 41 acts as housing for a UV-C lamp 43, and for at least one hyperspectral video camera, preferably at least two or three hyperspectral video cameras schematised in the figure and indicated with the reference 44.

The lamp 43 is preferably arranged so that the light beam is substantially perpendicular to the supporting surface 91 on the belt 42.

The hyperspectral video cameras 44 are preferably placed side by side at the centre of the supporting structure 41, aligned or positioned further forward or backward relative to the lamp 43, and are oriented substantially perpendicular to the supporting surface 91.

The second inspection unit 40 is also associated with a second control station 45, which integrates a control unit dedicated to controlling the lamp 43 of the hyperspectral video cameras 44 and optionally of the belt 42 and is equipped with an input/output interface 46.

A second selection unit 50 is arranged downstream of the second inspection unit. Said second selection unit 50 is preferably identical to the first selection unit 30 and has the same function.

Said second selection unit 50 is preferably controllable from the second control station 45.

The products that after inspection in the second inspection unit 40 are found to be still contaminated (or potentially contaminated), are conveyed by the second selection unit 50 toward the treatment block 300.

More in detail, in the variant of the system illustrated in Fig. 1, a first treatment unit 60 equipped with ozonator devices 61 is positioned downstream of the second selection unit 50. Said ozonator devices are mounted on a supporting structure 62 that forms a tunnel that is positioned above the belt 63 substantially for the whole of its length, as shown in Fig. 5.

The inner volume in the tunnel 62 is in communication with a suction device 64 suitable to draw in the excess ozone produced by the ozonator devices 61.

The products delivered from the belt 63 of the first treatment unit 60 are conveyed toward the second treatment unit 70, which is equipped with a plurality of UV-C tube lamps 71 arranged parallel along the direction of extension of the respective belt 72. The lamps 71 are mounted on a supporting frame 73 and are placed at a distance from the belt of around 20-40 mm.

According to a preferred variant, the second control station 45 of the second inspection unit 40 is configured also to control the first and the second treatment units. Alternatively, a further control station, common to both said units, or two further stations dedicated to the respective units can be provided.

In the variant illustrated, the treatment system comprises a third ionising radiation treatment unit 80. Said further treatment unit 80 comprises a chamber 81, through which the belt 82 passes, in which an X-ray generator tube (not illustrated in the figure) is placed.

Typically, said third treatment unit 80 is equipped with a dedicated control station 83, preferably integrated in the structure of the unit.

The present invention has been described purely for non-limiting illustrative purposes, according to some preferred embodiments. The person skilled in the art can find numerous other embodiments and variants, all falling within the scope of protection of the appended claims.