(19) & (11) EP 2 062 477 A1 (12) EUROPEAN PATENT APPLICATION published in accordance with Art. 153(4) EPC (43) Date of publication: (51) Int Cl.: 27.05.2009 Bulletin 2009/22 A01N 59/08 (2006.01) A01N 25/02 (2006.01) A01N 25/22 (2006.01) A01N 59/00 (2006.01) (2006.01) (2006.01) (21) Application number: 07806168.6 A01P 3/00 C01B 11/08 (22) Date of filing: 28.08.2007 (86) International application number: PCT/JP2007/066691 (87) International publication number: WO 2008/026607 (06.03.2008 Gazette 2008/10) (84) Designated Contracting States: (72) Inventor: GODA, Hisataka AT BE BG CH CY CZ DE DK EE ES FI FR GB GR Osaka-shi Osaka 541-0048 (JP) HU IE IS IT LI LT LU LV MC MT NL PL PT RO SE SI SK TR (74) Representative: Johnson, Terence Leslie Designated Extension States: Marks & Clerk AL BA HR MK RS 90 Long Acre London (30) Priority: 28.08.2006 JP 2006231280 WC2E 9RA (GB) (71) Applicant: Honbu Sankei Co., Ltd. Osaka-shi Osaka 540-0001 (JP) (54) PROCESS FOR PRODUCING AQUEOUS CHLOROUS ACID SOLUTION FOR USE AS BACTERICIDE (57) A process for producing aqueous chlorous acid in an amount which is equal to or larger than the amount solution in which chlorous acid, which is safe for the hu- necessary for a reduction reaction to thereby yield chlo- man body, is easy to handle, and less generates chlorine rous acid. Any one of inorganic acids, inorganic acid salts, dioxide, is yielded and used as a disinfectant for a pre- organic acids, and organic acid salts, or two or more treatment in food processing. To an aqueous sodium thereof, or a combination or these is added to the aque- chlorate solution is added sulfuric acid or an aqueous ous solution containing chlorous acid yielded, whereby solution thereof in such an amount and concentration the chlorous and acid can be present for long and the pH that the pH of the aqueous solution can be kept at 2.3-3.4 of the aqueous solution is regulated to regulated to to thereby react them and generate chloric acid. Subse- 3.2-7.0. Thus, high bactericidal power is imparted there- quently, hydrogen peroxide is added to the chloric acid to. EP 2 062 477 A1 Printed by Jouve, 75001 PARIS (FR) EP 2 062 477 A1 Description TECHNICAL FIELD 5 [0001] The present invention relates to a process for producing an aqueous chlorous acid solution used for disinfection/ sterilization of food for pretreatment in food processing operations and related facilities. BACKGROUND ART 10 [0002] Conventionally, chlorine oxides (e.g., chlorine, hypochlorous acid, chlorous acid, and chlorine dioxide) are primarily used for disinfection or sterilization of food for pretreatment in food processing operations, such as fresh perishable food including vegetables and fruits, and the facilities related to processing and production of processed food, such as containers, preparation/cooking machinery, and plant equipment. Of these, chlorine and hypochlorous acid, when reacted with organic compounds, are known to produce trihalomethanes, which are carcinogenic compounds. 15 This, along with recent health-consciousness trend, has focused attention on acidified sodium chlorite (ASC) solution, which was developed in the United States of America and which possesses a high bactericidal effect and is less associated with trihalomethane-related adverse effects. Reference 1 : U.S.A. Patent No. 6,524,624 20 [0003] To produce the above-mentioned ASC solution, an aqueous chlorous acid solution is mixed with an acid known as "generally recognized as safe" (GRAS) and adjusted to pH 2.3 to 3.2. [0004] However, the main active component of the above-mentioned ASC solution, chlorous acid, decomposes a short time after preparation due to its low stability, thereby reducing its bactericidal potential. The above-mentioned ASC 25 solution, therefore, needs to be prepared immediately before use. [0005] This preparation procedure is not only inconvenient but also associated with the disadvantages resulting from production of chlorine dioxide gas, which is highly likely to have toxic effects on individuals who inhale it and corrosive effects on food-processing and cooking machinery and other related equipment. 30 DISCLOSURE OF INVENTION PROBLEM TO BE SOLVED BY INVENTION [0006] The present invention was made taking into account the above disadvantages. The purpose of the present 35 invention is to provide an easy-to-handle, long-acting, stable aqueous chlorous acid solution. Another purpose of the present invention is to provide a disinfectant for use in pretreatment of food-processing operations that releases a reduced amount of chlorine dioxide, is safe to human health, and possesses a high bactericidal activity. MEANS FOR SOLVING PROBLEMS 40 [0007] In order to solve the aforementioned problems, a first feature of the process of the present invention is to employ a process for producing an aqueous chlorous acid solution for use as disinfectant, comprising: reacting an aqueous sodium chlorate solution with a volume and concentration of sulfuric acid or aqueous solution thereof appropriate for maintaining pH of said aqueous solution at 2.3 to 3.4, thereby generating chloric acid, and subsequently adding thereto 45 at least an amount of hydrogen peroxide required for reducing said chloric acid to produce chlorous acid. [0008] A second feature of the process of the present invention is to employ a process for producing an aqueous chlorous acid solution for use as disinfectant, comprising: reacting an aqueous sodium chlorate solution with a volume and concentration of sulfuric acid or aqueous solution thereof appropriate for maintaining pH of said aqueous solution at 2.3 to 3.4, thereby generating chloric acid, subsequently adding thereto at least an amount of hydrogen peroxide 50 required for reducing said chloric acid to produce chlorous acid, and adding to the resulting aqueous solution at least one compound selected from the group consisting of inorganic acids and salts or a combination thereof, to adjust its pH in the range of 3.2 to 7.0. [0009] A third feature of the process of the present invention is to employ a process for producing an aqueous chlorous acid solution for use as disinfectant, comprising: reacting an aqueous sodium chlorate solution with a volume and 55 concentration of sulfuric acid or aqueous solution thereof appropriate for maintaining pH of said aqueous solution at 2.3 to 3.4, thereby generating chloric acid, subsequently adding thereto at least an amount of hydrogen peroxide required for reducing said chloric acid to produce chlorous acid, and adding to the resulting aqueous solution at least one compound selected from the group consisting of inorganic and organic acids and salts or a combination thereof, to adjust its pH in 2 EP 2 062 477 A1 the range of 3.2 to 7.0. [0010] A forth feature of the process of the present invention is to employ a process for producing an aqueous chlorous acid solution for use as disinfectant, comprising: reacting an aqueous sodium chlorate solution with a volume and concentration of sulfuric acid or aqueous solution thereof appropriate for maintaining pH of said aqueous solution at 2.3 5 to 3.4, thereby generating chloric acid, subsequently adding thereto at least an amount of hydrogen peroxide required for reducing said chloric acid to produce chlorous acid, adding to the resulting aqueous solution at least one compound selected from the group consisting of inorganic acids and salts or a combination thereof, and further adding at least one compound selected from the group consisting of inorganic and organic acids and salts or a combination thereof, to adjust the pH in the range of 3.2 to 7.0. 10 [0011] A fifth feature of the process of the present invention is to employ the process for producing an aqueous chlorous acid solution for use as disinfectant, wherein said inorganic acid according to any of second to forth features of the present process, include carbonic acid, phosphoric acid, boric acid, or sulfuric acid. [0012] A sixth feature of the process of the present invention is to employ the process for producing an aqueous chlorous acid solution for use as disinfectant, wherein said inorganic salts according to any of second to fifth features 15 of the present process include carbonates, hydroxides, phosphates, or borates. [0013] A seventh feature of the process of the present invention is to employ the process for the process for producing an aqueous chlorous acid solution for use as disinfectant, wherein said carbonates according to the sixth feature of the present process include sodium carbonate, potassium carbonate, sodium bicarbonate, or potassium bicarbonate. [0014] A eighth feature of the process of the present invention is to employ the process for the process for producing 20 an aqueous chlorous acid solution for use as disinfectant, wherein said hydroxides according to the sixth or the seventh feature include sodium hydroxide or potassium hydroxide. [0015] A ninth feature of the process of the present invention is to employ the process for producing an aqueous chlorous acid solution for use as disinfectant, wherein said phosphates according to any one of sixth to eight features include disodium hydrogenphosphate, sodium dihydrogenphosphate, trisodium phosphate, tripotassium phosphate, 25 dipotassium hydrogenphosphate, or potassium dihydrogenphosphate. [0016] A tenth feature of the process of the present invention is to employ the process for producing an aqueous chlorous acid solution for use as disinfectant, wherein said borates according to any one of sixth to ninth features include sodium borate or potassium borate. [0017] A eleventh feature of the process of the present invention is to employ the process for producing an aqueous 30 chlorous acid solution for use as disinfectant, wherein said organic acids according to any one of third to tenth features include succinic acid, citric acid, malic acid, acetic acid, or lactic acid.