Field of the invention

[0001 ] The present invention generally finds application in the field of food treatment and particularly relates to a plant for sanitizing flours, grains and similar products.

[0002] The present invention also relates to a method for food treatment.

Background art

[0003] A number of food treatment processes are known for treating food such as flours, grains and the like, to reduce their initial moisture content and possibly sanitizing these products by removing or eliminating the bacterial or pathogenic load.

[0004] In common technologies, products undergo heat treatment, which raises their temperature to a predetermined value allowing sanitization.

[0005] For example, CN1 01623063 and US545141 8 disclose methods for treating cereal grain and flours, in which products are irradiated with an electromagnetic field having microwave frequencies, namely in a range from 91 5 MHz to 2450 MHz, which afford both moisture content and product sanitization.

[0006] Particularly, the heating effect produced by microwaves, with temperatures from 1 1 0 °C to 1 30 °C destroys heat sensitive pathogens.

[0007] Nevertheless, these relatively high temperature values also cause organoleptic degradation of products.

[0008] Furthermore, the use of such frequencies for the magnetic field was found to be ineffective toward other pathogenic organisms, such as toxins and mycotoxins, particularly fumonisin, which is one of the most frequently occurring and harmful mycotoxins in certain types of corns.

[0009] The presence of fumosin may be only eliminated or at least reduced using chemicals or biological methods.

[0010] For instance, CN1 01 822331 discloses a method of decontaminating grains from fumosin, which comprises dipping the contaminated products in a sodium carbonate or calcium hydroxide aqueous solution.

[0011 ] Nevertheless, the use of such methods appears to be not always appropriate, as the solutions employed therein may alter the properties of the treated food product. Furthermore, these known methods are also particularly complex and involve pollution problems.

[0012] On the other hands, other methods comprise controlling flours using particular optical sensors for distinguishing contaminated grains from uncontaminated grains, and rejecting the former. These arrangements involve high costs and, due to the use of sensor means, have a low throughput, as they require flours to be fed at low speed to allow scanning. Not the least, in this method the contaminated parts are simply rejected, and no sanitization or recovery thereof is provided.

Disclosure of the invention

[0013] The object of the present invention is to overcome the above drawbacks, by providing a plane for treating flours, grains and the like, that is highly efficient and relatively cost-effective.

[0014] A particular object is to provide a plant for treating flours, grains and the like, that can reduce the toxin content in the treated product with no organoleptic degradation thereof.

[0015] Another object is to provide a plant for treating flours, grains and the like, that affords a reduction of their initial moisture content.

[0016] A further object is to provide a plant for treating flours, grains and the like, that has a particularly environment-friendly, fast and inexpensive operation.

[0017] Another important object is to provide a plant for treating flours, grains and the like, that has a high throughput and substantially no waste.

[0018] These and other objects, as more clearly explained hereafter, are fulfilled by a plant for treating flours, grains and the like as defined in claim 1 .

[0019] With this particular configuration, the treated product will be sanitized from contaminants, such as toxins, mycotoxins and the like, without necessarily involving an excessive temperature increase, that would cause its organoleptic degradation.

[0020] Furthermore, the possibility of not using high temperatures for hot sanitization of products will reduce power consumption, whereby the process will have a lower cost and involve a lower impact on the environment.

[0021 ] In an additional aspect, the invention relates to a method for treating flours, grains and the like as defined in claim 6.

[0022] Advantageous embodiments of the invention are as defined in the dependent claims.

Brief description of the drawings

[0023] Further features and advantages of the invention will be more readily apparent upon reading of the detailed description of a preferred nonexclusive embodiment of a plant of the invention, which is shown as a non- limiting example with the help of the annexed drawings, in which:

FIGS. 1 and 2 are two distinct perspective views of the plant;

FIG. 3 is a front view of the plant of Fig. 1 ;

FIG. 4 is a side view of the plant of Fig. 1 ;

FIG. 5 is a top view of the plant of Fig. 1 .

Detailed description of a preferred embodiment

[0024] The annexed figures show a plant 1 for sanitization of flours, grains and similar products, which has the purpose of reducing both the initial moisture content in the products being treated and the pathogenic load thereof.

[0025] The plant of the invention is particularly directed to the treatment of such products in view of eliminating or at least reducing the load of toxins and mycotoxins, and particularly fumonisin and similar fungi that may be found in the product.

[0026] As more clearly shown below, the plant 1 of the invention will be adapted to treat any food flour, such as wheat flour, corn flour or the like, and corresponding grains.

[0027] As shown in Figs. 1 and 2, the plant essentially comprises a product feeding line 2, first treatment means 3 for reducing the relative moisture content in the product to be treated and second treatment means 4 for reducing the total mycotoxin content in the product to be treated, for sanitization thereof.

[0028] Particularly, the second treatment means comprise an applicator device 5, for generating an alternate electromagnetic field with a frequency falling within the radiofrequency range and for directing the field toward the feed line 2.

[0029] It was surprisingly found that this frequency range is particularly effective against certain pathogenic elements, and that the use of the radiofrequency electromagnetic field allows the pathogenic load in the starting product to be eliminated or at least reduced to safety values.

[0030] It was also found that the use of radiofrequencies is particularly effective against certain kinds of toxins and mycotoxins, such as those of the fumonisin family, which are frequently occurring mycotoxins in corn, and have a high toxicity degree, involving a hazard for human health. This mycotoxin has a long polymeric chain, and the electromagnetic field can break this chain and make fumonisin ineffective.

[0031 ] Preferred irradiation frequency values fall in a range from 5 MHz to 500 MHz. Particularly, usable frequencies may be selected from the frequency ranges admitted by the international standards for civil or industrial applications, whose central values are 6.78 - 1 3.56 - 27.1 2 - 40.68 - 433.92 MHz.

[0032] More preferably, the irradiated field may have a frequency ranging from 20 MHz to 50 MHz, optimal results being experimentally found to be already reached at such lower frequency values, e.g. at about 27.1 2 MHz or 40.68 MHz.

[0033] These values were experimentally found to result in a 30% reduction of the initial mycotoxin load.

[0034] These frequency values for the electromagnetic field also ensure a higher safety of the plant 1 as compared with microwave irradiation devices, which require complex and expensive shielding, due to the high hazards associated with the field at these frequencies.

[0035] Conveniently the feed line 2 comprises an inlet 6 for the products to be treated and an outlet 7 for the sanitized and at least partially dehumidified products.

[0036] Means 8 are also provided for continuously feeding the products between the inlet 6 and the outlet 7 at a substantially constant predetermined feeding speed.

[0037] The feed means 8 may be configured in various manners according to the type of product to be treated and may comprise, for example, a slide tube, a conveyor belt or other similar means.

[0038] Conveniently, the applicator device 5 is anyway equipped with radiating means 9 arranged at the periphery of at least one active portion 10 of the feed line 2, to define a predetermined sanitization area 1 1 .

[0039] The radiating means 9 will direct the electromagnetic field to the periphery of the active portion 1 0 and will substantially continuously irradiate the products that move through the sanitization area 1 1 .

[0040] As more clearly shown in Fig. 2, the feed line 2 comprises a feed conduit 1 2 which seamlessly extends from the inlet 6 to the outlet 7.

[0041 ] Particularly, the conduit 1 2 may have a serpentine shape, with substantially parallel straight longitudinal sections 1 2 joined by curved end sections 14.

[0042] Appropriate loading means 1 5 are provided at the inlet 6, for controlled supply of the product into the feed conduit 1 2 through the inlet 6.

[0043] If the product is a flour, the loading means 1 5 may comprise a hopper 6 with a discharge passageway 1 7 connected to the inlet 6 of the conduit 12 through valve means 28, such as a rotary valve, to control the feed rate of the product into the conduit 1 2.

[0044] In a preferred embodiment, the applicator device 5 comprises a radiofrequency electromagnetic wave generator, not shown, and a plurality of pairs of electrodes 1 8, 1 9, which are adapted to generate the electromagnetic field, as well as a voltage generator, also not shown, with electrodes 1 8, 19 connected to its poles.

[0045] The electrodes 1 8, 1 9 may have a substantially annular shape and be peripherally arranged, coaxial with corresponding straight sections 13 of the conduit 1 2, that form each an active portion 10 thereof.

[0046] The electrodes 18, 1 9 disposed at the periphery of the same straight section 1 3 are conveniently longitudinally offset with a substantially constant pitch. Also, appropriate electric connections are provided between the electrodes 18, 1 9 associated with contiguous straight sections 13.

[0047] The continuous feed means 8 comprise a blower 20 or a similar pump device having an air supply conduit 21 located upstream from the inlet 6 of the feed conduit 1 2, for blowing therein an air flow that is sufficient to allow the product to be fed at said feed rate.

[0048] Therefore, a predetermined amount of product to be treated will be continuously fed into the sanitization area 1 1 , through the electromagnetic field.

[0049] Conveniently, the product is fed into the sanitization area 1 1 at a substantially constant predetermined rate, which is adapted to ensure that the predetermined amount of product remains in the electromagnetic field for a sufficient predetermined maximum time to obtain the desired reduction of the pathogenic load, without excessively heating the product.

[0050] Those skilled in the art will understand that the rate values may be set according to the desired residence time of the products in the electromagnetic field, and will also depend on the length of such field in the direction of feed of the products.

[0051 ] Particularly, the optimal maximum residence time has been found to range from a few tenths of a second to 1 sec.

[0052] This will simultaneously provide sanitization and partial dehumidification of the product, without inducing excessive heating thereof.

[0053] Preferably, the first treatment means 3 may comprise a heating element 22, e.g. having one or more electrical resistors, located within the heating element and hence not shown, which is interposed between the supply conduit 21 of the blower 20 and the initial section 23 of the feed conduit 1 2.

[0054] The heating element 22 is adapted to heat up the air flow from the blower 20 before it enters the feed conduit 1 2 to provide further heating of the product to be treated and reduce its moisture content.

[0055] Preferably, the moisture content of the product may be reduced overall by a minimum value ranging from 1 % to 5% the initial moisture value, e.g. by about 2%. Such values may be obviously changed according to the initial moisture content of the product to be treated.

[0056] Preferably, the heating element 22 may be sized to obtain an air flow that, in the first section where it flows over the product, has a temperature ranging from 50 °C to 100 °C and preferably from 70 °C to 90 °C, e.g. substantially about 85 °C, such that the output product has a maximum temperature ranging from 30 °C to 70 °C, preferably about 40 °C.

[0057] Centrifugal separator means 24 are provided at the outlet 7 of the conduit 12 for centrifugal separation of the product, to separate the steam created during heating, that may be trapped in the product from the solid fraction thereof.

[0058] Particularly, the separator means 24 comprise a cyclone 25 which contains a separation chamber connected to the outlet 7 of the feed conduit 1 2 through a withdrawal pipe 26 and having a steam release pipe 27.

[0059] The above disclosure clearly shows that the plant of the invention fulfills the intended objects and particularly meets the requirement of ensuring sanitization and at least partial dehumidification of the products with no organoleptic degradation thereof.

[0060] In a further aspect, as shown in Fig. 6, the invention relates to a method of sanitizing flours, grains and similar products, which has the purpose of reducing both the initial moisture content in the products being treated and the pathogenic load thereof.

[0061 ] The method of the invention is particularly directed to elimination or at least reduction of the load of toxins and mycotoxins, such as fumonisin and similar fungi that may be found in the product.

[0062] The method of the invention will be adapted to treat any food flour, such as wheat flour, corn flour or the like, and corresponding grains.

[0063] The method essentially comprises a step a) of reducing the relative moisture content in the product to be treated and a step b) of reducing the total mycotoxin content in the product to be treated for sanitization.

[0064] Particularly, the step b) comprises c) applying an alternate electromagnetic field with a frequency that falls in the radiofrequency range.

[0065] It was surprisingly found that this frequency range is particularly effective against certain pathogenic elements, and that the use of the radiofrequency electromagnetic field allows the pathogenic load in the starting product to be eliminated or at least reduced back to safety values.

[0066] It was also found that the use of radiofrequencies is particularly effective against certain kinds of toxins and mycotoxins, such as those of the fumonisin family, which are frequently occurring mycotoxins in corn, and have a high toxicity degree, involving a hazard for human health. This mycotoxin has a long polymeric chain, and the electromagnetic field can break this chain and make fumonisin ineffective.

[0067] Preferred irradiation frequency values fall in a range from 5 MHz to 500 MHz.

[0068] Particularly, usable frequencies may be selected from the frequency ranges admitted by the international standards for civil or industrial applications, whose central values are 6.78 - 1 3.56 - 27.1 2 - 40.68 - 433.92 MHz.

[0069] More preferably, the irradiated field may have a frequency ranging from 20 MHz to 50 MHz, optimal results being experimentally found to be already reached at such lower frequency values, e.g. at about 27.1 2 MHz or 40.68 MHz.

[0070] These values were experimentally found to result in a 30% reduction of the initial mycotoxin load.

[0071 ] The sanitization step b) comprises a step d) of directing the electromagnetic field into a predetermined sanitization area.

[0072] Therefore, a predetermined amount of product to be treated will be continuously fed (step e) into the sanitization area, through the electromagnetic field.

[0073] For example, the product to be sanitized may be fed from a loading area, through appropriate feed means designed according to the type of product to be treated.

[0074] For instance, the feed means may comprise a conveyor belt, a flow pipe or the like, having a portion in the sanitization area.

[0075] Conveniently, the product is fed into the sanitization area at a substantially constant predetermined rate, which is adapted to ensure that the predetermined amount of product remains in the electromagnetic field for a sufficient predetermined maximum time to obtain the desired reduction of the pathogenic load, without excessively heating the product.

[0076] Those skilled in the art will understand that the rate values may be set according to the desired residence time of the products in the electromagnetic field, and will also depend on the length of such field in the direction of feed of the products.

[0077] Particularly, the optimal maximum residence time has been found to range from a few tenths of a second to 1 sec.

[0078] This will simultaneously provide sanitization and partial dehumidification of the product, without inducing excessive heating thereof.

[0079] Nevertheless, the step a) may be also carried out by further heating the product to be treated to reduce its moisture content by a predetermined minimum value, ranging from 1 % to 5% the initial moisture value, e.g. about 2%.

[0080] Such values may be changed according to the initial moisture content of the product to be treated.

[0081 ] The heating step a) may be carried out both upstream and downstream from the sanitization step b), or at least partially simultaneously with it. [0082] For example, the heating step a) may comprise a step f) of blowing a hot air stream having a predetermined temperature on the predetermined amount of product to be treated.

[0083] Preferably, the temperature of the air stream in the first section where it flows over the product, has a temperature ranging from 50 °C to 1 00 °C and preferably from 70 °C to 90 °C, e.g. substantially about 85 °C, such that the output product has a maximum temperature ranging from 30 °C to 70 °C, preferably about 40 °C.

[0084] Conveniently, the hot air stream may be adapted to allow a continuous feed of the predetermined amount of product through the electromagnetic field.

[0085] In this case, the air stream is blown from a location upstream from the feed means.

[0086] At the end of the sanitization and dehumidification process, a final step may be provided of g) centrifuging the sanitized product to separate the steam created during heating, that may be trapped in the product, from the solid fraction.

[0087] The plant and method of the invention are susceptible of many changes and variants within the inventive principle disclosed in the annexed claims. All the details thereof may be replaced by other technically equivalent parts, and the materials may vary depending on different needs, without departure from the scope of the invention.

[0088] While the plant and method have been described with particular reference to the annexed figures, the numerals referred to in the disclosure and claims are only used for the sake of a better intelligibility of the invention and shall not be intended to limit the claimed scope in any manner.