Method of reducing the aflatoxin contact of oilseed meal products

Abstract

There is disclosed a method of reducing the aflatoxin content of all contaminated oilseed meal products. A homogeneous mixture comprising the product, from 10 to 40 percent by weight of water, at least one oxide and/or hydroxide of an .[.alkali metal or.]. alkaline earth metal, and at least one organic amine is formed. The quantity of oxide and/or hydroxide is such that the mixture has a pH of at least 8. The quantity of organic amine is such that this pH is raised to at least 9.5 percent. The mixture is reacted at a temperature below 150° C. to reduce the aflatoxin content of the mixture to less than 100 parts per thousand million. The detoxified mixture is then dried.

We claim: 
     
       1. A method of reducing the aflatoxin content of an aflatoxin contaminated oilseed product having .Iadd.an aflatoxin content of about 500 to 2000 ppb. and .Iaddend.a fats content less than 10 percent, which comprises the steps of: a. forming a homogeneous mixture comprising: the crushed product, from 10 to 40 percent by weight of water, at least one basic agent selected from the group consisting of the oxides and hydroxides of .[.alkali metals and.]. alkaline earth metals in an amount such that the homogeneous mixture has a pH of least 8, and at least one organic amine in an amount .Iadd.of from about 0.1 to 0.6% by weight, the amount of said organic amine being .Iaddend.sufficient to further raise the pH to at least 9.5;   b. reacting the homogeneous mixture by maintaining the product at a temperature between room temperature and 150° C. for a time sufficient to reduce the aflatoxin content of the product to less than 100 ppb; and   c. drying the resulting detoxified product to reduce its water content.   
     
     
       2. The method according to claim 1, wherein .[.the amount of organic amine in the homogeneous mixture is from 0.1 to 0.6 percent by weight.]. .Iadd.and said basic agent is lime which is present in said homogeneous mixture in an amount of about 2% by weight based on weight of said oilseed product.Iaddend.. 
     
     
       3. The method according to claim 1, wherein the homogeneous mixture is maintained at a temperature below 150° C. for a time sufficient to reduce the aflatoxin content in the product to less than 50 ppb. 
     
     
       4. The method according to claim 1, wherein the mixture is reacted at a pressure greater than atmospheric pressure. 
     
     
       5. The method according to claim 4, wherein the mixture is continuously mixed during the reaction. 
     
     
       6. The method according to claim 1, wherein the reaction is carried out at a temperature between 70° and 150° C. and at a pressure greater than atmospheric pressure, and the mixture is continuously mixed during reaction. 
     
     
       7. The method according to claim 1, wherein the product is peanut oil meal. 
     
     
       8. The method according to claim 1, wherein the organic amine is selected from the group consisting of methylamine, dimethylamine, trimethylamine and ethylamine or mixtures thereof. 
     
     
       9. The method according to claim 1, wherein the basic agent is selected from the group consisting of calcium oxide, calcium hydroxide, .[.sodium hydroxide and potassium hydroxide.].. 
     
     
       10. The method according to claim 5, wherein an extruder having an endless worm is used for mixing, and the speed of rotation of the worm is such that the duration of reaction is from 1 to 10 minutes. 
     
     
       11. The method according to claim 10, wherein the extruded detoxified product is crushed before drying. 
     
     
       12. The method according to claim 1, wherein the detoxified product is dried to a moisture content of from 5 to 10 percent. 
     
     
       13. The method according to claim 12, wherein phosphoric acid is added to the dried product in a quantity sufficient to bring the pH of the product to a value not exceeding 7. 
     
     
       14. The method according to claim 1 wherein said homogeneous mixture is pelletized prior to the reacting of said mixture. 
     
     
       15. The method according to claim 1 wherein said dried detoxified product is formed into feed oil cakes. .Iadd. 16. The method according to claim 1 wherein said homogeneous mixture comprises calcium oxide or calcium hydroxide in an amount of about 2% by weight and wherein the pH of said homogeneous mixture is raised to a maximum of about 10 by the addition of said amine. .Iaddend. .Iadd. 17. The method according to claim 1 wherein said oilseed product is peanut oil meal, said basic agent is selected from the group consisting of calcium oxide and calcium hydroxide and is present in said homogeneous mixture in an amount of about 2% by weight, said organic amine is selected from the group consisting of methyl amine, dimethyl amine, trimethyl amine and mixtures thereof and the pH of said homogeneous mixture is raised to a maximum of about 10 by the addition of said amine, and wherein the reaction is carried out at a temperature between 70° and 150° C. and pressure greater than atmospheric pressure and the mixture is continuously mixed during the reaction.