METHOD FOR THE PROPHYLACTIC TREATMENT OF A FOOD PRODUCT SILO

Abstract

A method for the prophylactic treatment of the development of parasites in a food product storage silo, the food product storage generating the deposit of food product scraps and/or dust on the walls of the silo, said prophylactic treatment method comprising the application, to at least one part of the walls, of a layer comprising at least 10 g of mineral per m.sup.2 of wall, the mineral being chosen from: an alkali metal bicarbonate, an alkaline-earth metal carbonate, an alkali metal sulphate, an alkaline-earth metal sulphate, an alkaline-earth metal oxide, and mixtures thereof; the mineral being in the form of particles having an average diameter of at most 200 μm; and said method being characterized in that the application of the layer is carried out after emptying of the silo, on food product scraps and/or dust deposited on the walls of the silo.

Claims

1. A method for producing a barrier between parasites and food product scraps and/or dust which are attached to a wall of a food product storage silo after emptying of the silo, the method comprising: using a layer comprising a mineral on the wall of the silo, wherein the mineral is selected from the group consisting of: an alkali metal bicarbonate, an alkali metal carbonate, an alkaline-earth metal carbonate, an alkali metal sulphate, an alkaline-earth metal sulphate, an alkaline-earth metal oxide, and mixtures thereof, the mineral being in the form of particles having an average diameter of at most 200 μm, and the layer comprising at least 10 g of the mineral per m.sup.2 of wall.

2. The method according to claim 1, wherein the mineral is selected from the group consisting of: sodium bicarbonate, potassium bicarbonate, trona, sodium carbonate, potassium carbonate, calcium carbonate, magnesium carbonate, dolomite, sodium sulphate, potassium sulphate, calcium sulphate, magnesium sulphate, magnesium oxide, and mixtures thereof.

3. The method according to claim 2, wherein the mineral is sodium bicarbonate or trona.

4. The method according to claim 1, wherein the layer additionally comprises a co-formulant of the mineral, the co-formulant being selected from the group consisting of: a silica, a diatomaceous earth, an alkaline-earth metal silicate, a clay, a montmorillonite, a zeolite, and mixtures thereof.

5. The method according to claim 1, wherein the layer is obtained by application of the mineral to the wall by sprinkling, brushing or spraying the mineral in the form of an aqueous suspension of the mineral, then drying.

6. The method according to claim 1, wherein the layer comprising the mineral is an adhesive layer, and wherein the layer applied to a sheet of galvanized metal of 0.01 m.sup.2 placed horizontally thereby providing an upper face of the sheet, the layer being applied to the upper face thereby forming a coated face, retains, after the sheet of galvanized metal has been turned over and placed with the coated face facing the ground, at least 80% of the mineral after one hour.

7. The method according to claim 1, wherein the layer comprising the mineral is a pulverulent layer, and wherein said layer applied to a horizontal sheet of galvanized metal of 0.01 m.sup.2, then subjected, at a distance of 60 cm, for 10 minutes, to a jet of air of 2 bar having an initial air speed of 14 m/s, loses at least 20% of the mineral.

8. The method according to claim 1, wherein the layer comprises at most 200 g of mineral per square meter of wall.

9. The method according to claim 1, wherein the layer fills at least part of the crevices of the wall.

10. The method according to claim 1, wherein the layer is applied from February to June in the northern hemisphere or from August to December in the southern hemisphere on the wall of the empty food product storage silo.

11. (canceled)

12. A method for a prophylactic treatment of development of parasites in a food product storage silo, the silo comprising walls, and the food product storage generating deposit of food product scraps and/or dust on the walls of the silo after emptying of the silo, said prophylactic treatment method comprising application to at least part of the walls of a mineral selected from the group consisting of an alkali metal bicarbonate, an alkali metal carbonate, an alkaline-earth metal carbonate, an alkali metal sulphate, an alkaline-earth metal sulphate, an alkaline-earth metal oxide, and mixtures thereof, the mineral being in the form of particles having an average diameter of at most 200 μm, the mineral being applied as a layer comprising at least 10 g of the mineral per m.sup.2 of wall, and wherein the application of the layer is carried out after emptying of the silo, on food product scraps and/or dust deposited on the walls of the silo.

13. A method for preventing an increase in population of parasites in a food product storage silo without significantly increasing, the silo comprising walls, and the food product storage generating deposit of food product scraps and/or dust on the walls of the silo after emptying of the silo, said method comprising application to at least part of the walls of a mineral selected from the group consisting of an alkali metal bicarbonate, an alkali metal carbonate, an alkaline-earth metal carbonate, an alkali metal sulphate, an alkaline-earth metal sulphate, an alkaline-earth metal oxide, and mixtures thereof, the mineral being in the form of particles having an average diameter of at most 200 μm, the mineral being applied as a layer comprising at least 10 g of the mineral per m.sup.2 of wall, and wherein the application of the layer is carried out after emptying of the silo, on food product scraps and/or dust deposited on the walls of the silo.

14. The method according to claim 1, wherein the layer is non-parasiticidal.

15. The method according to claim 1, without being parasite-repellent.

16. The method according to claim 1, wherein the layer is obtained by application of the mineral and optionally of a co-formulant of the mineral, by powdering.

17. The method according to claim 1, wherein the layer additionally comprises a co-formulant of the mineral, the co-formulant containing silica.

18. The method according to claim 12, wherein the mineral is sodium bicarbonate or trona.

19. The method according to claim 12, wherein the layer additionally comprises a co-formulant of the mineral, the co-formulant being selected from the group consisting of: a silica, a diatomaceous earth, an alkaline-earth metal silicate, a clay, a montmorillonite, a zeolite, and mixtures thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0058] The present invention thus relates to:

[0059] a method for the prophylactic treatment of the development of parasites in a food product storage silo, and

[0060] a use of a layer of mineral for producing a barrier between parasites and their food,

as described hereinafter

[0061] Item 1. Method for the prophylactic treatment of the development of parasites in a food product storage silo, the silo comprising walls, and the food product storage generating the deposit of food product scraps and/or dust on the walls of the silo after emptying of the silo,

[0062] said prophylactic treatment method comprising the application to at least one part of the walls:

[0063] of a mineral chosen from: an alkali metal bicarbonate, an alkali metal or alkaline-earth metal carbonate, an alkali metal or alkaline-earth metal sulphate, an alkaline-earth metal oxide, and mixtures thereof,

[0064] the mineral being in the form of particles having an average diameter of at most 200 μm,

[0065] the mineral being applied as a layer comprising at least 10 g of the mineral per m.sup.2 of wall, and

[0066] said method being characterized in that the application of the layer is carried out, after emptying of the silo, on food product scraps and/or dust deposited on the walls of the silo.

[0067] Item 2. Method according to item 1, according to which the mineral is chosen from: sodium bicarbonate, potassium bicarbonate, trona, sodium carbonate, potassium carbonate, calcium carbonate, magnesium carbonate, dolomite, sodium sulphate, potassium sulphate, calcium sulphate, magnesium sulphate, magnesium oxide, or mixtures thereof.

[0068] Item 3. Method according to item 2, according to which the mineral is sodium bicarbonate or trona.

[0069] Item 4. Method according to any one of items 1 to 3, according to which a co-formulant of the mineral, chosen from: a silica, a diatomaceous earth, an alkaline-earth metal silicate, a clay, a montmorillonite, a zeolite, or mixtures thereof, is applied to the walls with said mineral.

[0070] Item 5. Method according to item 4, according to which the co-formulant of the mineral is chosen from: calcium stearate, magnesium stearate, precipitated silica, fumed silica, silica gel, sodium silicate, potassium silicate, anhydrous magnesium silicate, magnesium silicate hydrate, iron silicates, kaolin, bentonite, smectite, montmorillonite, perlite, diatomaceous earth, pyrophyllite, attapulgite, vermiculite, sepiolite, expanded perlite, and mixtures thereof.

[0071] Item 6. Method according to any one of items 1 to 5, according to which the mineral, and the co-formulant of the mineral if present, is (are) in the form of particles, such that at least 50% by weight of the particles have a diameter of less: than 100 μm, preferably than 70 μm, more preferably than 40 μm, even more preferably than 30 μm, also preferably such that at least 90% by weight of the particles have a diameter of less: than 100 μm, preferably than 70 μm, more preferably than 40 μm, even more preferably than 30 μm.

[0072] Item 7. Method according to item 4, according to which the mineral comprises one or more mineral(s) soluble at ambient temperature in water at a concentration of at least 50 g for 1000 g of water, and the co-formulant of the mineral is sparingly soluble in water, namely soluble at ambient temperature at a concentration of at most 10 g for 1000 g of water.

[0073] Item 8. Method according to item 7, according to which the mineral comprises sodium bicarbonate and the co-formulant of the mineral is silica.

[0074] Item 9. Method according to any one of items 1 to 8, according to which the mineral comprises at least 60%, advantageously at least 70%, more advantageously at least 80%, even more advantageously at least 85% by weight of sodium bicarbonate. In the present invention, the mineral may also consist essentially of sodium bicarbonate.

[0075] Item 10. Method according to any one of items 4 to 9, according to which a co-formulant of the mineral is applied with the mineral and is in a proportion by weight of at most 20% or of at most 15% relative to the mineral.

[0076] Item 11. Method according to any one of items 1 to 9, according to which the mineral, and the co-formulant of the mineral if present, is (are) free of neurotoxic pesticide. In particular, the mineral, and the co-formulant of the mineral if present, contain(s) neither pyrethrum nor synthetic pyrethroids, such as permethrin.

[0077] Item 12. Method according to any one of items 1 to 11, according to which the mineral, and the co-formulant of the mineral if present, is (or are) applied as a layer by powdering.

[0078] Item 13. Method according to any one of items 1 to 11, according to which the application of the mineral to the walls is carried out by sprinkling, brushing or spraying the mineral in the form of an aqueous suspension of the mineral, then drying.

[0079] Item 14. Method according to item 13, according to which the application is carried out by spraying the mineral in the form of an aqueous suspension of the mineral in the form of droplets, and such that at least 70% by weight of the droplets have a size of less than 500 μm.

[0080] Item 15. Method according to any one of items 1 to 14, according to which the layer comprising the mineral is an adhesive layer, characterized in that the layer applied to a sheet of galvanized metal of 0.01 m.sup.2 placed horizontally, the layer being applied to the upper face, retains, after the sheet of galvanized metal has been turned over and placed with the coated face facing the ground, at least 80% of the mineral after one hour, advantageously after one week, more advantageously after 60 days.

[0081] Item 16. Method according to any one of items 1 to 15, according to which the layer comprising the mineral is a pulverulent layer, characterized in that such a layer applied to a horizontal sheet of galvanized metal of 0.01 m.sup.2, then subjected, at a distance of 60 cm, for 10 minutes, to a jet of air of 2 bar having an initial air speed of 14 m/s, loses at least 20% of the mineral.

[0082] Item 17. Method according to any one of items 1 to 16, according to which the layer comprises at most 200 g, preferably at most 100 g, more preferably at most 40 g of mineral per square metre of wall.

[0083] Item 18. Method according to any one of items 1 to 17, according to which the layer is applied to the walls of the silo in order to fill at least one part of the crevices of the walls.

[0084] Item 19. Method according to any one of items 1 to 18, according to which the application is carried out from February to June in the northern hemisphere (or August to December in the southern hemisphere) on the walls of the empty food product storage silo.

[0085] Item 20. Method according to any one of items 1 to 19, according to which the amount of mineral used for the prophylactic treatment is at most 100, advantageously at most 50, more advantageously at most 30 g of mineral per metric ton of storable or stored food products.

[0086] Item 21. Method for storing food products in a silo, according to which a prophylactic treatment method according to any one of items 1 to 20 is applied to the silo, then the silo is filled with food products pretreated with a pesticide before storage of the food products in the silo.

[0087] Item 22. Method for storing food products in a silo, according to which a prophylactic treatment method according to any one of items 1 to 20 is applied to the silo, then the silo is filled with food products not pretreated with a neurotoxic pesticide before storage of the food products in the silo.

[0088] Item 23. Method for storing food products in a silo according to item 22, according to which the silo is filled with food products not pretreated with a pesticide before storage of the food products in the silo.

[0089] Item 24. Method for storing food products according to any one of items 21 to 23, according to which, after the application of the mineral to the silo, the silo is filled with food products, and the food products are subject to one or more cooling steps in order to lower their temperatures to at most 10° C.

[0090] Item 25. Method for storing food products according to item 24, according to which the cooling in order to lower the temperature of the food products to at most 10° C. is carried out by ventilation with cool air, in particular with cool air having a temperature at most 8 to 10° C. lower than the temperature of the food products.

[0091] Item 26. Use of a mineral chosen from: an alkali metal bicarbonate, and alkali metal carbonate, an alkaline-earth metal carbonate, an alkali metal sulphate, an alkaline-earth metal sulphate, an alkaline-earth metal oxide, and mixtures thereof, the mineral being in the form of particles having an average diameter of at most 200 μm, for the prophylactic treatment of the development parasites in a food product storage silo,

[0092] the silo comprising walls and food product scraps and/or dust attached to the walls, said prophylactic treatment consisting of the application of the mineral to said food product scraps and/or dust attached to the walls, as a layer comprising at least 10 g of the mineral per m.sup.2 of wall.

[0093] Item 27. Use of a mineral according to item 26, making it possible to limit parasite access to the food product scraps or dust and to prevent the parasites from feeding thereon.

[0094] Item 28. Use of a layer of mineral on the wall of a food product storage silo, wherein food product scraps and/or dust are attached to the walls of the silo after emptying of the silo, for producing a barrier between parasites and the food product scraps and/or dust, characterised in that

[0095] the mineral is chosen from: an alkali metal bicarbonate, an alkali metal or alkaline-earth metal carbonate, an alkali metal or alkaline-earth metal sulphate, an alkaline-earth metal oxide, and mixtures thereof,

[0096] the mineral being in the form of particles having an average diameter of at most 200 μm, and

[0097] the layer comprising at least 10 g of the mineral per m.sup.2 of wall.

[0098] Item 29. Use according to item 28, according to which the mineral is chosen from: sodium bicarbonate, potassium bicarbonate, trona, sodium carbonate, potassium carbonate, calcium carbonate, magnesium carbonate, dolomite, sodium sulphate, potassium sulphate, calcium sulphate, magnesium sulphate, magnesium oxide, or mixtures thereof.

[0099] Item 30. Use according to item 29, according to which the mineral is sodium bicarbonate or trona.

[0100] Item 31. Use according to any one of items 28 to 30, according to which the layer additionally comprises a co-formulant of the mineral, the co-formulant being selected from: a silica, a diatomaceous earth, an alkaline-earth metal silicate, a clay, a montmorillonite, a zeolite, and mixtures thereof

[0101] Item 32. Use according to any one of items 28 to 31, according to which the layer is obtained by application of the mineral to the walls by sprinkling, brushing or spraying the mineral in the form of an aqueous suspension of the mineral, then drying.

[0102] Item 33. Use according to any one of items 28 to 32, according to which the layer comprising the mineral is an adhesive layer, characterized in that the layer applied to a sheet of galvanized metal of 0.01 m.sup.2 placed horizontally, the layer being applied to the upper face, retains, after the sheet of galvanized metal has been turned over and placed with the coated face facing the ground, at least 80% of the mineral after one hour, advantageously after one week, more advantageously after 60 days.

[0103] Item 34. Use according to any one of items 28 to 32, according to which the layer comprising the mineral is a pulverulent layer, characterized in that such a layer applied to a horizontal sheet of galvanized metal of 0.01 m.sup.2, then subjected, at a distance of 60 cm, for 10 minutes, to a jet of air of 2 bar having an initial air speed of 14 m/s, loses at least 20% of the mineral.

[0104] Item 35. Use according to any one of items 28 to 34, according to which the layer comprises at most 200 g, preferably at most 100 g, more preferably at most 40 g of mineral per square metre of wall.

[0105] Item 36. Use according to any one of items 28 to 35, according to which the layer fills at least part of the crevices of the walls.

[0106] Item 37. Use according to any one of items 28 to 36, according to which the layer is applied from February to June in the northern hemisphere (or August to December in the southern hemisphere) on the walls of the empty food product storage silos.

[0107] Item 38. Use of the layer of mineral on the wall of a food product storage silo, wherein food product scraps and/or dust are attached to the walls of the silo after emptying of the silo, for preventing an increase in population of parasites in the food product storage silo without significantly increasing, preferably without increasing the mortality of the parasites compared to their mortality in the absence of food, characterised in that

[0108] the mineral is chosen from: an alkali metal bicarbonate, an alkali metal or alkaline-earth metal carbonate, an alkali metal or alkaline-earth metal sulphate, an alkaline-earth metal oxide, and mixtures thereof,

[0109] the mineral being in the form of particles having an average diameter of at most 200 μm, and

[0110] the layer comprising at least 10 g of the mineral per m.sup.2 of wall.

[0111] Item 39. Method for preventing an increase in population of parasites in a food product storage silo without significantly increasing, preferably without increasing the mortality of the parasites compared to their mortality in the absence of food, the silo comprising walls, and the food product storage generating deposit of food product scraps and/or dust on the walls of the silo after emptying of the silo,

[0112] said method comprising the application to at least part of the walls

[0113] of a mineral chosen from: an alkali metal bicarbonate, an alkali metal or alkaline-earth metal carbonate, an alkali metal or alkaline-earth metal sulphate, an alkaline-earth metal oxide, and mixtures thereof, [0114] the mineral being in the form of particles having an average diameter of at most 200 μm, [0115] the mineral being applied as a layer comprising at least 10 g of the mineral per m.sup.2 of wall, and
said method being characterized in that the application of the layer is carried out after emptying of the silo, on food product scraps and/or dust deposited on the walls of the silo.

[0116] Item 40. The use or method according to any of the preceding claims which is non-parasiticidal.

[0117] Item 41. The use or method according to any of the preceding claims which is without being parasite-repellent.

[0118] Item 42. The use or method according to any one of items 28 to 41, according to which the mineral, and the co-formulant of the mineral if present, is (are) in the form of particles, such that at least 50% by weight of the particles have a diameter of less: than 100 μm, preferably than 70 μm, more preferably than 40 μm, even more preferably than 30 μm, also preferably such that at least 90% by weight of the particles have a diameter of less: than 100 μm, preferably than 70 μm, more preferably than 40 μm, even more preferably than 30 μm.

[0119] In the present invention, the minerals are either natural, or produced synthetically.

[0120] In one preferred mode of the present invention, the mineral and/or the co-formulant of the mineral are food additives. The term “food additive” is intended to mean the compounds listed in and corresponding to the Codex Alimentarius of the FAO/WHO—version 2013.

[0121] Furthermore, the minerals or the co-formulants of minerals listed in the present specification, in particular those listed in items 2 to 5, are usable in organic agriculture according to EC regulation 834/2007.

[0122] Among the minerals listed in items 1 to 3, sodium bicarbonate is particularly advantageous since, in addition to being authorized by various organizations (such as the FDA in the United States) in human or animal food, it is has very favourable toxicological and eco-toxicological profiles and is well tolerated by all living organisms such as humans and mammals. For example, the plasma and blood of human beings naturally contains it at a concentration of about 1200 mg/1, and it holds an important pH-regulating role for these fluids.

[0123] The co-formulants of items 4 to 6 may be in amorphous or crystalline form. However, it is preferred for them to be in amorphous form, that is to say in non-crystalline form. This is particularly the case for co-formulants containing silica. In this respect, non-crystalline precipitated silicas or non-crystalline fumed silicas are particularly recommended in the present invention.

[0124] The examples that follow are intended for illustrating the invention. They should not be interpreted as limiting the scope of the invention claimed.

EXAMPLES

Example 1

[0125] In this example, the effectiveness of a barrier layer of a mineral consisting of a sodium bicarbonate (Solvay Bicar® Food grade 0/4), with an average laser particle size of 25 μm, deposited at various thicknesses: respectively 17 and 34 g/m.sup.2, was tested. In order to see the effectiveness of the barrier layer on the food uptake of insects, three insect populations were tested: [0126] Tribolium confusum, [0127] Sitophilus granarius (grain weevil), [0128] Ephestia kuehniella (flour moth).

[0129] The food product chosen was of two types: [0130] ground wheat (in order to simulate food product scraps), [0131] wheat flour (T55) (in order to simulate food product dust).

[0132] The food product tested was deposited on a galvanized iron plate, in an amount of 20 g/m.sup.2 in order to simulate the food product scraps or dust on a silo wall after emptying.

[0133] The layer of mineral was deposited on the layer of milled wheat or on the layer of flour by spraying the mineral in aqueous suspension at 50% by weight, and was then dried in order to form the barrier layer of minimal either at 17 or at 34 g/m.sup.2.

[0134] The insect populations were pre-starved for 10 days without being fed.

[0135] The three pre-starved insect populations were then fractionated and distributed onto various sheet metal plates: [0136] without milled wheat or flour (i.e. without food), [0137] with milled wheat or flour (i.e. with food) at 20 g/m.sup.2 and 0 g/m.sup.2 of mineral (i.e. without mineral layer), [0138] with milled wheat or flour (i.e. with food) at 20 g/m.sup.2 and 17 g/m.sup.2 of mineral, [0139] with milled wheat or flour (i.e. with food) at 20 g/m.sup.2 and 34 g/m.sup.2 of mineral (i.e. a mineral layer twice as great as the one at 17 g/m.sup.2).
The mortality rate expressed as percent of each insect population was monitored over the course of 10 days (after the 10 days where the insects were pre-starved). The sheet metal plates covered with food allowed the insect populations to have something to eat and to feed themselves suitably over the course of the 10 days of the test with maximum mortality rates observed after 10 days on the control populations of: [0140] Tribolium: 1% [0141] Sitophilus: 2% [0142] Ephestia: 6%.
Table 1 hereinafter gives the mortality rate of the insect populations as a function of the number of days of exposure on the sheet metal plates: [0143] without food [0144] or with food (20 g/m.sup.2) and coated with 17 or 34 g/m.sup.2 of layer of mineral. It is observed that, in the presence of the layer of mineral on the layer of food (scraps or dust), the insects can virtually not feed: the mortality rate of the insects as a function of time is slightly less than or equal to the mortality rate of the control tests without accessible food. The mortality rate is 100% after 7 to 9 days with food and mineral layer (tests 4 to 15), while the mortality rate of 100% of the insects without food (tests 1 to 3) is reached after 7 days on the control tests This shows that the barrier layer of mineral has a very high effectiveness for preventing food-product insect pests from reaching scraps or flour located under the layer of mineral, and thus preventing development of said insect pests.

TABLE-US-00001 TABLE 1 Insect population mortality (%) vs. Number of days' exposure on control plates (no food) or on plates with food and mineral layer Mineral Insect population mortality (%) vs. Number of days exposure layer 1 2 3 4 5 6 7 8 9 10 Ref Food Test conditions g/m.sup.2 Insects day days days days days days days days days days 1 No food No food 0 Tribolium 0 0 5 26 58 91 100 100 100 100 2 No food No food 0 Sitophilus 0 0 1 5 46 79 100 100 100 100 3 No food No food 0 Ephestia 0 0 2 7 62 94 100 100 100 100 4 Milled wheat 20 g/m.sup.2 Food + Mineral layer 17 Tribolium 0 0 2 17 41 79 96 100 100 100 5 Milled wheat 20 g/m.sup.2 Food + Mineral layer 17 Sitophilus 0 0 0 6 37 72 91 100 100 100 6 Milled wheat 20 g/m.sup.2 Food + Mineral layer 17 Ephestia 0 1 3 9 57 87 100 100 100 100 7 Milled wheat 20 g/m.sup.2 Food + Mineral layer 34 Tribolium 0 0 3 21 60 84 100 100 100 100 8 Milled wheat 20 g/m.sup.2 Food + Mineral layer 34 Sitophilus 0 1 3 6 41 76 95 100 100 100 9 Milled wheat 20 g/m.sup.2 Food + Mineral layer 34 Ephestia 0 1 4 10 56 88 100 100 100 100 10 Milled Flour 20 g/m.sup.2 Food + Mineral layer 17 Tribolium 0 0 3 9 34 55 82 100 100 100 11 Milled Flour 20 g/m.sup.2 Food + Mineral layer 17 Sitophilus 0 1 3 7 23 57 76 91 100 100 12 Milled Flour 20 g/m.sup.2 Food + Mineral layer 17 Ephestia 0 0 2 6 40 67 85 100 100 100 13 Milled Flour 20 g/m.sup.2 Food + Mineral layer 34 Tribolium 0 1 2 11 39 60 87 100 100 100 14 Milled Flour 20 g/m.sup.2 Food + Mineral layer 34 Sitophilus 0 2 2 5 28 61 82 98 100 100 15 Milled Flour 20 g/m.sup.2 Food + Mineral layer 34 Ephestia 0 1 3 8 51 76 92 100 100 100

Example 2

[0145] In this example, use was made, as mineral, of a sodium bicarbonate (Solvay Bicar® Food grade 0/4), with an average laser particle size of 25 μm, and a co-formulant of the mineral composed of amorphous silica (Solvay Tixosil® 38 AB Food grade), with an average laser particle size of 25 μm (weight-average diameter). The mineral and co-formulant are both of food grade.

[0146] The weight-average diameter is measured by laser diffraction and scattering on a Malvern Mastersizer S particle size analyser using an He—Ne laser source having a wavelength of 632.8 nm and a diameter of 18 mm, a measurement cell equipped with a backscatter 300 mm lens (300 RF), and an MS 17 liquid preparation unit, using ethanol saturated with bicarbonate at ambient temperature (22° C.).

[0147] The mineral and the co-formulant of the mineral were introduced into a Lödige ploughshare powder mixer and the powder was mixed for 5 minutes so as to obtain a homogeneous powder. A suspension of the mineral and of the co-formulant of the mineral was then prepared by pouring 10 kg of the powder obtained (85% sodium bicarbonate and 15% silica) into 10 litres of water while dispersing the mineral and co-formulant with a shearing agitator, and a homogeneous suspension containing 50% by weight of mineral and of co-formulant was obtained.

[0148] The aqueous suspension of mineral and of fluidizer was applied by spraying by means of a piston pump at a pressure of 40 bar and at a flow rate of 3 litres per minute, onto the walls of a concrete cereal storage silo freshly emptied in February, on a layer of 20 g of the mineral and co-formulant assembly, per m.sup.2 of wall. The concrete walls before treatment were clean but partially covered with small scraps and dust from wheat grains. The aqueous suspension adhered to the cereal scraps and dust to form a layer of mineral and co-formulant on the cereal scraps and dust.

[0149] A concrete silo juxtaposed with respect to the treated silo, having the same size and made of the same concrete, and emptied in February, of the same wheat harvest, was not treated according to the present method in order to produce a control.

[0150] In July, the two silos: the treated one and the non-treated control silo, were filled with the same harvest of non-treated wheat grains of organic grade.

[0151] From July to October, the silos were cooled by injection of cold air overnight in order to gradually lower the temperature of the grain to 8+/−1° C.

Example 3

[0152] In this example, the effectiveness of barrier layers of different minerals was tested. It was also tested whether these barrier layers exhibit any parasiticidal effect. As minerals trona, sodium carbonate, magnesium carbonate, magnesium oxide and sodium sulphate were tested. All minerals had an average particle diameter of below 70 μm. All tested mineral powders contained w/w of amorphous silica. The minerals were applied as an aqueous slurry containing 50% w/w of mineral formulation. The barrier layers were prepared by spraying the aqueous slurry on a metal plate at a dose of 18 g dry solid/m.sup.2 and drying the thus obtained layer.

[0153] Experiments were conducted under four different test conditions. Under condition 1, the insects were placed on the metal plate without any food and without any mineral layer. Under condition 2, A and B first a mix of crushed wheat and flour (T55) was deposited on the metal plate at a dose of 20 g/m.sup.2. Under condition 2, the insects were placed on the food layer without any mineral layer. Under condition A, the mineral layer was sprayed onto the food layer and after drying, insects and available food in a petri dish were placed on the dry mineral layer. Under condition B, the mineral layer was sprayed onto the food layer and after drying, the insects were placed on the dry mineral layer without any additional food.

[0154] Three insect populations were tested: [0155] Tribolium confusum (TC) [0156] Sitophilus oryzae (SO) [0157] Ephestia kuehniella (EK).

[0158] All insects were pre-starved for 10 days without being fed before testing.

[0159] The mortality rate expressed as percent of each insect population was monitored over the course of 10 days (after the 10 days where the insects were pre-starved).

[0160] Table 2 hereinafter gives the mortality rate of the insect populations as function of the number of days of exposure on the metal plates.

TABLE-US-00002 TABLE 2 Food Available (on metal Mineral food 0.5 1 2 3 4 5 6 7 8 9 10 Condition plate) layer) (in Petri dish) Insects day day days days days days days days days days days 1   No food No treatment No food TC 0 2 3 8 11 31 86 100 100 100 100 (on metal SO 0 0 1 8 15 76 100 100 100 100 100 plate) EK 0 4 8 13 16 84 100 100 100 100 100 2   Crushed No treatment No food TC 0 0 1 3 3 5 11 12 12 12 12 wheat & flour SO 0 0 0 0 0 2 4 4 4 5 5 (20 g/m.sup.2) EK 0 1 1 3 5 7 9 12 15 16 16 3A Crushed Trona Available TC 0 2 2 4 6 9 13 13 15 15 15 wheat & flour food (in a SO 0 0 2 4 4 4 5 7 7 8 9 (20 g/m.sup.2) petri dish) EK 0 0 2 3 7 11 12 12 14 14 14 on mineral layer 3B Crushed Trona No food TC 0 0 2 5 8 23 40 65 82 100 100 wheat & flour SO 0 0 2 7 18 34 64 76 93 100 100 (20 g/m.sup.2) EK 0 1 3 7 9 72 87 90 100 100 100 4A Crushed Sodium Available TC 0 0 0 1 2 2 5 7 9 10 10 wheat & flour Carbonate food (in a SO 0 1 1 1 2 3 4 4 6 6 6 (20 g/m.sup.2) petri dish) EK 0 0 1 2 3 6 6 10 11 11 13 on mineral layer 4B Crushed Sodium No food TC 0 1 2 5 8 20 67 83 92 100 100 wheat & flour Carbonate SO 0 0 1 7 11 71 96 100 100 100 100 (20 g/m.sup.2) EK 0 1 3 8 12 78 93 100 100 100 100 5A Crushed Magnesium Available TC 0 1 1 3 5 7 10 10 11 11 11 wheat & flour carbonate food (in a SO 0 0 0 1 2 2 2 4 5 6 6 (20 g/m.sup.2) petri dish) EK 0 0 0 1 3 5 9 10 10 10 12 on mineral layer 5B Crushed Magnesium No food TC 0 0 2 3 9 17 45 71 88 100 100 wheat & flour carbonate SO 0 0 0 5 11 24 56 73 94 100 100 (20 g/m.sup.2) EK 0 0 1 3 5 64 81 92 100 100 100 6A Crushed Magnesium Available TC 0 0 1 3 5 8 8 9 10 10 11 wheat & flour oxide food (in a SO 0 0 0 1 2 3 5 5 5 6 7 (20 g/m.sup.2) petri dish) EK 0 0 1 1 2 4 5 7 9 11 11 on mineral layer 6B Crushed Magnesium No food TC 0 0 2 6 9 11 19 38 47 56 69 wheat & flour oxide SO 0 0 1 1 2 6 15 49 72 91 100 (20 g/m.sup.2) EK 0 1 2 4 7 16 30 43 56 70 82 7A Crushed Sodium Available TC 0 1 1 2 4 4 6 6 8 8 9 wheat & flour sulphate food (in a SO 0 0 2 3 3 3 3 3 3 5 6 (20 g/m.sup.2) petri dish) EK 0 0 0 1 2 5 6 8 8 9 10 on mineral layer 7B Crushed Sodium No food TC 0 0 0 2 7 13 19 31 49 71 83 wheat & flour sulphate SO 0 0 2 2 3 14 18 39 55 73 85 (20 g/m.sup.2) EK 0 0 1 2 5 12 24 49 62 91 100

[0161] From the data in Table 2, it is evident that the mortality rate of insects on a metal plate without access to any food significantly increases after about 5 days (condition 1). In the presence of food, but without any mineral layer (condition 2) the mortality rate is rather low even after 10 days.

[0162] If the layer of crushed wheat and flour on the metal plate is coated with a mineral layer of trona (condition 3B), sodium carbonate (condition 4B) or magnesium carbonate (condition 5B) and no other food is available to the insects, the mortality rate increases significantly after about 5 days and is similar to the one observed in the absence of any food. This demonstrates that the mineral forms an effective barrier layer between the crushed wheat and flour on the metal plate and the insects.

[0163] In case where magnesium oxide (condition 6B) or sodium sulphate (condition 7B) are used as barrier layer, the mortality rate of the insects significantly increases after about 7 days. This demonstrates that the barrier layer comprising magnesium oxide or sodium sulphate is slightly less pronounced compared to barrier layers comprising trona, sodium carbonate or magnesium carbonate. Nevertheless, also magnesium oxide and sodium sulphate are still suitable for forming the desired barrier layer.

[0164] Furthermore, if the insects are provided with food in a petri dish placed on the mineral layer (conditions 3A, 4A, 5A, 6A and 7A), their mortality rate is similar to the mortality rate in the absence of any mineral layer on the crushed wheat and flour (condition 2). This demonstrates that the mineral layer only prevents the insects from accessing their food without being harmful to the insects as such. If food is available to the insects, they survive on the mineral layer showing substantially the same mortality as without any mineral layer. Thus, the mineral layer is non-parasitical.

Example 4

[0165] Example 3 was repeated but using Bi-Ex® (97% w/w sodium bicarbonate+anti-caking agent; available from Solvay) and sodium bicarbonate (mixture of 95 w/w sodium bicarbonate and 5% w/w amorphous silica) as mineral. In both cases the average diameter of the mineral particles was below 70 μm. The results are summarized in Table 3 hereinafter.

TABLE-US-00003 TABLE 3 Mineral layer Available (g/m2 dry Food food product) Exposition time (day) (on metal (in Petri on food located 1 2 3 4 5 6 7 8 9 10 Condition plate) dish) on metal plate Insects day days days days days days days days days days 1 No food / No treatment TC 0 1 2 15 39 77 93 100 100 100 (on metal SO 0 0 4 8 58 100 100 100 100 100 plate) EK 0 1 5 9 71 100 100 100 100 100 2 Crushed / No treatment TC 0 0 2 3 6 6 9 9 11 13 wheat & SO 0 0 1 2 3 5 6 7 7 8 flour EK 0 0 2 2 3 5 9 11 12 15 (20 g/m.sup.2) 3 Crushed / Bi-Ex (30 g/m.sup.2) TC 0 1 3 8 31 55 79 93 100 100 wheat & SO 0 0 3 6 44 82 91 99 100 100 flour EK 1 2 4 6 74 91 100 100 100 100 (20 g/m.sup.2) 4 Crushed Available Bi-Ex (30 g/m.sup.2) TC 0 0 1 1 2 4 7 6 8 9 wheat & food (in a SO 0 0 1 1 2 5 8 9 10 11 flour petri dish) EK 0 1 2 3 6 8 9 9 10 13 (20 g/m.sup.2) on mineral layer 5 Crushed / sodium TC 0 0 3 11 26 63 88 96 100 100 wheat & bicarbonate (18 SO 0 1 4 9 41 76 88 100 100 100 flour g/m.sup.2) EK 0 3 6 13 67 84 92 100 100 100 (20 g/m.sup.2) 6 Crushed Available sodium TC 0 0 0 0 0 1 1 1 1 1 wheat & food (in a bicarbonate (18 SG 0 0 0 0 0 0 0 0 1 1 flour petri dish) g/m.sup.2) EK 0 0 0 0 2 2 4 4 5 6 (20 g/m.sup.2) on mineral layer

[0166] From the data above it is evident that the mortality rate of the insects on the mineral layer covering the layer of crushed wheat and flour (conditions 3 and 5) is similar to their mortality rate in the absence of any food and mineral layer (condition 1). Thus, the mineral layer acts as barrier between the insects and their food. Furthermore, if additional food is present in a petri dish on the mineral layer (conditions 4 and 6), the mortality rates are similar to the mortality rate in case where the insects have access to the crushed wheat and flour without any mineral layer (condition 2). This confirms that the mineral layer is not harmful to the insects and in particular is non-parasiticidal.