WO1994009635A1

WO1994009635A1 - Starch-iodine-peroxide preservation of foods

Info

Publication number: WO1994009635A1
Application number: PCT/US1993/009111
Authority: WO
Inventors: Edward Shanbrom
Original assignee: Edward Shanbrom
Priority date: 1992-10-26
Filing date: 1993-09-24
Publication date: 1994-05-11

Abstract

The treatment foodstuffs, liquid and solid, with starch-iodine-hydrogen peroxide or other iodine-binding starch-containing compositions, and equivalents is disclosed.

Description

STARCH-IODINE-PEROXIDE PRESERVATION OF FOODS

Field of the Invention This invention relates to the treatment and preservation of foods and drinks. According to the invention complexes of iodine with amylose-containing starchier se, or components of starch, e.g. amylose or amylopectin, and analogous iodine- binding polysaccharides and derivatives thereof, all of which are referred to generally and collectively as "starch" hereinafter, unless otherwise indicated by context, are used in the treatment of foods and drinks. Thereafter a physiologically compatible reducing agent such as an ascorbate salt, as an additive or on a solid support, e.g. in a bed or filter of solid albumin, starch, povidone, etc,, may be used to remove the last traces of biocidal iodine. The treatment and preparation of fruits, vegetables, meats, juices, milk, and other foods are contemplated.

Background of the Invention Most uncooked agricultural food products and many processed food products cany bacteria, viruses, etc., some of which are pathogenic. Milk and fermentation beverages, wine and beer, typically carry heavy loads of bacteria, most of which are harmless to humans; however, the risk of the presence of pathogenic microbes is ever present. Such liquid foodstuffs are severely degraded as to flavor and/or texture by cooking or canning. Pasteurization satisfactorily inactivates most pathogenic microbes in such products; however, pasteurization is an expensive process and alters the natural flavor of such products.

Meats, poultry meats especially, are frequent carriers of pathogenic organisms. Salmonella, for example, is a frequent contaminant of meats and a nearly universal contaminant of fresh and frozen poultry. Processed meats, bacon, ham, sausages of all kinds, are typically treated with sodium nitrite to prevent the propagation of pathogenic and spoiling microorganisms. While modern animal husbandry in the United States has greatly reduced the proportion of pork that is contaminated by trichinosis, the threat of contaminated meat weighs heavily in most countries of the world. Vegetables and fruits grown in soils fertilized with or contaminated with human excrement are frequently contaminated with any of a great many pathogenic organisms. In many countries, it is necessary to wash or scrub vegetables with hypochlorite or other irritating solutions before they can be eaten. Numerous potential pathogens may be present-tl.e surface of fruits and vegetables or, in the case of milk, on the skin and membranes of the milk-producing animals. It is desirable for the growth of such disease-producing microorganisms to be inhibited and preferable for these microorganisms to be destroyed.

Iodine is an outstanding microbicide, with an extraordinary range of action. Part of its mode of action is that it is able to penetrate the cell walls of microorganisms rapidly, and block certain essential hydrogen-bonding in amino acids. Also, it has a powerful, oxidizing effect on S-H, -S-S- groups, which are essential factors in protein production. It is effective against a wide range of microorganisms, including bacteria, tubercle bacilli (Mycobacteria), fungi, protozoa, lipid and medium viruses, as well as non-lipid and small viruses. Iodine is designated as an inter-mediate germicide only, because spores are not readily killed with weak concentrations. However, iodine has the greatest degerming efficiency compared to the other halogens, chlorine and bromine, since it is deactivated by proteins at least three times slower than chlorine and four times slower than bromine. Iodine has the additional advantage that its disinfecting properties are independent of the pH value of it's environment. Therefore, unlike chlorine, for example, iodine would not be rendered ineffective in an acid pH. It would likewise not be deactivated quickly in an alkaline pH. Low concentrations of iodine react relatively slowly as compared with proteins in general and therefore it remains available to react with bacteria to which it generally has a greater affinity. It is in this way that iodine can exhibit its unique advantageous selectivity towards microorganisms while maintaining a very low level of cytotoxicity to the host cells. However, because of iodine's physical and inherent chemical properties, its use as an antiseptic, broad-spectrum antimicrobial has been limited because state of the art delivery methods allows for the liberation of too much free iodine which can be toxic to living cells.

The use of water soluble complexes of polyvinyl pyrrolidone iodine complex (PVPA) as disclosed in U.S. Pat. No 4,128,633. Such use is illustrative of a complex of iodine and an organic carrier commonly known as an iodophor. This complexing of iodine "harnesses" the iodine, thereby controlling its rate of release.

Iodophors are loose complexes of elemental iodine or triodide, solubilizers, and a polymeric carrier that serves, not only to increase the solubility of the iodine, but also to tame the iodine to provide a sustained release reservoir for the iodine. The carriers, heretofore, have been neutral water soluble polymers, with mainly polyvinyl pynolidones as the principal commercialized polymer. Polyether glycols, polyacrylic acids, polyamides, polyoxyalkylenes, starches and polyvinyl alcohol also form iodophors. Upon dilution, these iodophor complexes form micellar aggregates, which are dispersed, upon dilution, with water or bodily fluids, and the iodine linkage to the polymer is progressively weakened until the iodine can be regarded as free to generate antimicrobial concentrations. These iodine complexes in aqueous solution have the advantage over pure, elemental iodine solutions, in that because they are present in far less concentration they greatly reduce irritation to tissue, unpleasant odor, staining of tissue and conosion of metal surfaces such as surgical instruments, but dissipate relatively quickly because of their miscibility and reaction with body fluids. Generally, when such a complex is in equilibrium with the aqueous phase, and then diluted, the solution will have increased availability of free iodine within a given fixed volume. These iodophors. because of their water solubility, therefore tend to dissipate their antimicrobial action quickly, because as a solution, then, are water miscible and react relatively quickly with proteins and organic materials generally while reacting with the bacteria. The concentrations of iodine in water-based systems can be much higher than what is required for its antimicrobial intent, and iodine is dissipated by side reactions with body fluids, resulting in the iodine reservoir being prematurely used up. However, their limited iodine reserves and dilution factors have meant that such iodophors are effective for a given disinfecting purpose for a limited time only.

Microorganisms that have survived the initial application, because of limited longevity of the antimicrobial agent, may act as a seed to cause the pathogen population to rise again to its initial level. Most water miscible broad-spectrum antimicrobials exhibit this deficiency. Continuous application of the antimicrobial agent to the site is therefore required, to inhibit the increase in population.

A major disadvantage of PVP/1 complexes is that their safe and efficacious antimicrobial action is limited to use on skin or, in some cases, on intact nr.cosa. This is because their water solubility, as mentioned above, results irr excess releases of free iodine when introduced into relatively large volumes of liquid. Considering that as little as 0.2 PPM of iodine is sufficient to kill enteric bacteria (10 minutes at 25@ C), and under the same conditions, 3.5 PPM and 14.6 PPM of iodine, respectively, are sufficient to kill amoebic cysts and enteric viruses, PVP/1 complex solutions can instantaneously introduce thousands of excess parts of available iodine in one burst (i.e., an uncontrolled burst of solution).

Efforts to treat meats, for example, to eliminate contaminants have been made. Hydrogen peroxide has been evaluated as a bactericide in poultry chilling water to kill bacteria that reside on the carcasses of poultry prepared for use as a food, Lillard H S; Thomson J E, J Food Sci 48 (1), 1983, J 25-126 (abstract). While bacterial kills could be obtained, the poultry carcasses were degraded to the point where they would be unacceptable in the marketplace.

Iodine was officially recognized by the pharmacopeia of the United States in 1930, also as tincture iodine (tincture of iodine) and linimentum iodi (liniment of iodine). Iodine has an unpleasant odor. In addition, it stains with an intensive yellow-brownish color and combines with iron and other metals, its solutions are not stable, it irritates animal tissue, and is a poison.

Although exact details about the killing of a living cell by the I₂ molecule (or one of the reaction products occurring in aqueous solution) are not known, it can be assumed that iodine reacts:

(1) With basic N-H functions that are parts of some amino acids (e.g., lysine, histidine, arginine) and the bases of nucleotides (adenine, cytosine, and guanine) forming the conesponding N-iodo derivatives. By this reaction, important positions for hydrogen bonding are blocked, and a lethal disorder of the protein structure may occur. (2) Oxidizing the S-H group of the amino acid cysteine, through which the connections of protein chains by disulfide (-S-S-) bridges, as an important factor in the synthesis of proteins, are lost.

(3) With the phenolic group of the amino acid tyrosine, forming mono- or diiodo-derivatives. In this case, the bulk of the iodine atom(s) in the ortho position may cause a form of steric hindrance in the hydrogen bonding of the phenolic OH group.

(4) With the carbon-carbon double bond (C=C) of the unsaturated fatty acids. This could lead to a change in the physical properties of the lipids and membrane immobilization.

Iodine is consumed by proteinaceous substrates and its efficacy as a disinfectant is reduced at certain antiseptic applications. This is due to a reducing effect of the material to be disinfected which leads to the conversion of iodine into non-bactericidal iodide. Thus, not only the reservoir of available iodine is diminished but also the equilibrium of triiodide is influenced as well. Both of these effects cause a decrease in the proportion of free germicidal iodine, the actual anti-microbial agent. Iodine is an excellent, prompt, effective microbicide with a broad range of action that includes almost all of the important health-related microorganisms, such as fungi, bacteria, viruses, bacterial viruses, and protozoan cysts, if the sometimes severe limitations inherent in its use are overcome. Mycobacteria and the spores of bacilli and clostridia can be killed by iodine. As to be expected, varying amounts of iodine are necessary to achieve complete disinfection of the different classes or organisms. Within the same class, however, the published data on the disinfecting effect of iodine correspond only to a small extent. In particular, the published killing time of spores and viruses are widely disparate.

Various authors have tried to summarize the disinfecting properties of iodine and the other halogens by reviewing the literature and analyzing the existing data. The most important conclusions are: (1) A standard destruction (i.e., a 99.999% kill in 10 minutes at 25o C) of enteric bacteria, amoebic cysts, and enteric viruses requires I₂ residuals of 0.2, 3.5, and 14.6 ppm, respectively. (2) On a weight basis, iodine can inactivate viruses more completely over a wide range of water quality than other halogens.

(3) In the presence of organic and inorganic nitrogenous substances, iodine is the cysticide of choice because it does not produce side reactions that interfere with its disinfecting properties.

(4) Iodine would require the smallest mg/L dosage compared to chlorine or bromine to "break any water" to provide a free residual.

(5) I₂ is 2 to 3 times as cysticidal and 6 times as sporicidal as HOI, while HOI is at least 40 times as virucidal as I₂. This behavior is explained on the one hand by the higher diffusibility of germicidal iodine through the cell walls of cysts and spores and on the other hand by the higher oxidizing power of HOI.

Gottardi, W. Iodine and Iodine Compounds in DISINFECTION, STERILIZATION,

AND PRESERVATION, Thiπl Edition, Block, Seymour S., Ed., Lea & Febiger, Philadelphia, 1983, and the references cited therein provide more details respecting the background discussed above.

The classic blue starch-iodine complex is well-known and the reaction of iodine with starch is used as an indicator reaction in may diverse types of iodine analysis. It is also known that starch-iodine complexes have some biocidal activity,

Rosenblatt, S., U.S. Patent No. 5,071,648, Dec. 10, 1991, although no comprehensive studies of this activity have been identified.

Solid beads of cross-linked beads of starch-iodine that absorb moisture from wounds, etc., and also provide a source of iodine are well-known; see, e.g., Holloway, G. Allen, Jr.; Johansen, Kaj H.; Barnes, Robert W.; Pierce, George E., Multicenter trial of cadexomer iodine to treat venous stasis ulcer, Western Journal of Medicine. vl51 nl, p35(4), July, 1989. Cadexomer iodine (IODOSORB® PERSTORP CARBOTEC®, Perstorp, Sweden), is a starch polymer bead similar to dextranomer but with iodide (0.9% weight per weight) bonded to the polymer. When fluid contacts the beads, substantial amounts of fluid— as much as 6 ml per gram of cadexomer iodine—are absorbed, as well as bacteria within the fluid. Bonded iodine becomes bactericidal in this milieu. Other somewhat limited descriptions of the use of starch-iodine have also been published. For example, Glushankof S I, et al, Russian patent SU 1204575, describes compositions for purification and decontamination of water that contains starch, aluminum sulphate, iodine, iodide and activated charcoal to produce drinking water from open reservoir., in_~field conditions. A starch-based disinfectant composition prepared by treating starch suspension with potassium permanganate followed by a solution of iodine in potassium permanganate is described by Tatarov P G, et. al., Russian patent SU 979363 821207. One would infer that the product described by Glushankof, et al, is a solid bed of charcoal coated or containing the starch, iodine, and aluminum sulfate.

A protective coating for stored fruit and vegetables containing slurried starch, iodine, potassium iodide and sodium bicarbonate is described by Popova E R, et. al., Russian Patent SU 959733, 820928.

Iodine starch for disinfection is described by Mochnacz, W. et. al., Ptitsevodstvo, 1980, 11, p. 37; Zh.. Vet. 1981, Abstr. No. 38226. (Amyloiodine as bactericides, disinfectants, antiseptics, fungicides, fungistats, virucides and virustats; (CAS REGISTRY NUMBERS: 7553-56-2).

Johansson, J. A. O., U.S. Patent 4,010,259, describes the manufacture of cross-linked, swellable hydrophilic polymer-iodine complexes, including cross- linked starch-iodine complexes. Johansson discloses the following possible uses of the insoluble, water-swellable cross-linked compositions he produced: Cosmetic and pharmaceutical materials in various forms, gels, sprays and powders for example, such as foot powder, baby powder, body deoderants, skin cleansers and creams; disinfectants for skin and wounds, preventing hospital infections and vaginal disinfectants; disinfection of water in, e.g. swimming pools and cooling towers; disinfection of equipment; and in the transportation and storage of commodities such as milk, wine and beer. In all instances, the iodine-containing product contemplated by Johansson is a swellable, insoluble solid material. Removal by filtration, etc., is contemplated in some applications, i.e. in the transportation and storage of commodities. Bactericidal water filter , Panzer, Hans W. P.; Brown, Jerry Hugh, France patent FR 1462968, CA: 67(14)67490m, describes water purification by filtration and sterilization by iodine.

The use of soluble organo-iodine compounds in water purification is, of course, well-known. One of the more popular water purifiers is tetraglycine hydroperiodide, which is widely used because of its effectiveness against giardia.

Iodine has also been used to treat swimming pools, etc., but is objectionable because it irritates the eyes and stains the pool walls an unattractive yellow color.

Mehltretter, C.L., et al, U.S. Patent 3414515 discloses the disinfection of swimming pools with a non-irritating deeply blue iodine complex of a hydroxyalkyl ether of starch and of starch-containing starches that masks the yellow color of iodine in water.

The production of atri-iodide of betaamaylose is described by Minto, W.L., U.S. Patent No. 2540486. Smith, Frederick R., International Publication No. WO85/02422, 6 June

1985, discloses alloy fiber products, including fibers per se and fabrics woven or otherwise formed from fibers, that include iodine. Starch-iodine containing fibers are disclosed.

Hydrogen peroxide (H₂O₂), mol wt 34.016, is a weakly acidic, clear colorless liquid, miscible with water in all proportions. The four atoms are covalently bound in a nonpolar H— O--O--H structure. It is now prepared primarily by anthraquinone autoxidation processes. It is used widely to prepare other peroxygen compounds and as a nonpolluting oxidizing agent. The reactions of hydrogen peroxide are: Decomposition: 2H₂O₂ - 2H₂O + O₂

Molecular additions: H₂O₂ + Y -» Y.H₂O₂

Substitutions: H₂O₂ + RX → ROOH + HX

H₂O₂ + 2 RX → ROOR + 2 HX Oxidations: H₂O₂ + W -. WO + H₂O Reductions: H₂O₂ + Z → ZH₂ + O₂ Hydrogen peroxide may react directly or after it has first ionized or dissociated into free radicals, ^n many cases, the reaction mechanism is extremely complex and may involve catalysis or h depender.. upon the reaction environment.

Hydrogen peroxide can forπrfree radicals by homolytic cleavage of either an O--H bond or the O--O bond.

HOOH → H. +.OOH (380 X mol or 90 kcal/mol) HOOH → 2.OH (210 Kj/mol or 50 kcal/mol) The last equation predominates in uncatalyzed vapor-phase decomposition and photochemically initiated reactions. In catalytic reactions, especially in solution, the nature of the reactants determines which reaction is predominant.

Hydrogen peroxide is a strong oxidant and most of its uses and those of its derivatives depend on this property. It oxidizes a wide variety of organic and inorganic compounds, ranging from iodide ions to color bodies of unknown structure in cellulosic fibers. Hydrogen peroxide reduces stronger oxidizing agents such as chlorine.

Aqueous hydrogen peroxide is sold in grades ranging from 3 to 98%, mainly containing 35, 50, 70, or 90% H₂O₂. The 3-6% H₂O₂ solutions for cosmetic and medicinal use are obtained by diluting a more concentrated grade, usually with the addition of extra stabilizer. There is a USP specification for 3% H₂O₂. Hydrogen peroxide is irritating to the skin, eyes, and mucous membranes.

However, low concentrations (3-6%) are used in medicinal and cosmetic applications.

Hydrogen peroxide is used to treat wastewaters and sewage effluents, and to control hydrogen sulfide generated by the anaerobic reaction of raw sewage in sewer lines or collection points. It has been proposed as a supplemental oxygen source for overloaded activated sludge plants. It reportedly controls denitrification in secondary clarifiers and improves bulking conditions. It has been used as a flotation assistant. It has been generated in a wastewater reservoir by the cathodic reduction of oxygen. Hydrogen peroxide has been used with povidone iodine in biocidal processes. A number of such methods are described in the following patents to Witkin, et al. Simon, Gilbert I; Witkin, Roy T, US Patent 4997625 910305, describe the treatment of dental and medical instruments and appliances to be chemically sterilized by immersion in an admixture of an iodophor such as the povidone iodine complex or a quaternary ammonium compound such as cetyl pyridinium chloride and a peroxide such as H₂O₂, the antimicrobial action of the iodine derived from the iodophor being enhanced or potentiated by oxygen released from the peroxide.

The invention is applicable also to the chemical sterilization of surgical sites.

Witkin, Roy T, US Patent 4935248 900619, describes applying, spraying, or sponging antimicrobially effective amounts of aqueous iodophor peroxide solutions to the udder surfaces of cows, or other animals to be milked prior to milking. The udders are shampooed with a nonstaining shampoo containing iodine in a povidone-iodine complex and hydrogen peroxide as a nascent oxygen source.

Simon, Gilbert I; Witkin, Roy T, US Patent 4738840 880419, US Patent

4592489 860603, and US Patent 4567036 860128, describe pre- and post-operative dental and surgical procedures in and on structures and areas of the oral cavity to maintain sterility by the application of an antimicrobially enhanced aqueous solution of an iodophor constituting a source of iodine and a peroxide as a source of oxygen. The iodophor is preferably a povidone iodine complex soluble in water and the peroxide is preferably hydrogen peroxide, the oxygen from the peroxide acting to enhance the antimicrobial activity of the iodine derived from the povidone iodine complex.

Witkin, Roy T, US Patent 5066497 911119, discloses an antimicrobial veterinary composition having enhanced, antimicrobial activity against a broad spectrum of microorganisms afflicting small and large animals. The composition is a solution or mixture of povidone iodine complex and nascent oxygen obtained from a peroxide source.

Hydrogen peroxide has been combined directly with povidone to provide a dry powder source of H₂O₂.

Garelick Paul; Login, Robert B; Merianos, John J, US Patent 5066488 911119, describe a semi-anhydrous, suspension process for preparing substantially anhydrous complexes of PVP and H₂O₂ containing about 18% to about 22% by weight H₂O₂. The process comprises suspending substantially anhydrous PVP and an aqueous solution of 70 to 85% H₂O₂ in an anhydrous ethyl acetate medium to precipitate a free-flowing, fine white powders of the complex, and filtering and drying under vacuum at about 40-50°C. to form the desired p. duct.

Lieberman, Herbert A; Login, Robert B; Merianos, John J, US Patent 5008106 910416, describe a method of using the product referred to by Garelick, et al, ibid, for reducing the microbial content of surfaces which comprises contacting said surface with a microbiocidal amount of a substantially anhydrous complex of PVP and H₂O₂.

Biss Russell B; Cohen Jeffrey; Merianos John J; Taylor Paul D, US Patent 5077047 911231, also describe a process for the production of pvp-H₂O₂ products in the form of free-flowing powders. A fluidized bed maintained at a reaction temperature of about room temperature to 60°C. is contacted with finely divided droplets of a 30 to 85% by weight aqueous H₂O₂ solution. A 50-70% H₂O₂ solution is used, and the feed rate of introduction of the H,O₂ solution is about 5-50 g/minute/kg PVP present. The pvp-H₂O₂ product preferably contains about

15-24%, preferably 18-22%, H₂O₂ (1:1 molar ratio) and less than about 5% water.

It is generally recognized that proteinaceous materials destroy the biocidal effectiveness of iodine and iodophors such as PVP-I. This factor has been considered a major impediment to the use of iodine and iodophors in the presence of large amounts of biological materials. Albumin has been identified as having and extremely high capability of de-activating the biocidal power of iodine and iodophors. For example, Batts W N; Landolt M L; Winton J R, Appl Environ Microbiol 57 (5). 1991, 1379-1385, reported the results of using iodine in fishery waters to kill virus that iodine efficacy decreased when proteinaceous material was added to the water. Bovine serum albumin blocked iodine inactivation of the virus more effectively than did equal concentrations of fetal bovine serum or river sediment. Batts, et al, also noted that sodium thiosulfate effectively neutralized free iodine.

Starch-iodine-hydrogen peroxide (Starch-I-H₂O₂) is, to the best of applicant's knowledge, a new composition of matter. It is an object of this invention to provide a method for sterilizing foods in a manner that will to minimize the addition of foreign chemicals thereto by the use f starch iodine-hydrogen peroxide.

Summary of the Invention The present invention encompases processes of treating foods, both solid and liquid, that may carry or contain bacteria, virus, or other pathogenic organisms to sterilized the same by reaction with starch-iodine-hydrogen peroxide.

Starch-iodine-hydrogen peroxide may be iodine and hydrogen peroxide complexed with essentially the entire starch molecule, or any of the great variety of amylose-containing starches available from different sources, or with a polysaccharide component, or derivative thereof, of starch, or an equivalent polysaccharide, that binds to starch, starch and amylopectin being the most widely available of these materials. In the case of starch-iodine-hydrogen peroxide treatment of liquids, e.g. milk, fruit juices, fruit juice concentrates, etc., in the liquid phase, amylose-iodine-hydrogen peroxides are preferred because of the total solubility of amylose complexes. Such treatment may, however, desirably be carried out by passing the liquid through a bed or filter of solid starch-iodine- hydrogen peroxide.

Thereafter, if it is desired to assure total iodine removal and removal of hydrogen peroxide, the solution can be passed into contact with solid starch, e.g. filtered through a bed or column of solid starch particles that are less than saturated with iodine and hydrogen peroxide, preferably having no more than a trace of iodine, or another absorbing material, such as cross-linked povidone to remove the excess iodine. Cross-linked starch and amylose products such as those described by Holloway, G. Allen, Jr.; Johansen, Kaj H.; Barnes, Robert W.; Pierce,

George E., Multicenter trial of cadexomer iodine to treat venous stasis ulcer,

Western Journal of Medicine. vl51 nl, p35(4), July, 1989; Johansson, J. A. O.,

U.S. Patent 4,010,259,; and White, Frederick R, International Publication No.

WO85/02422, without added iodine and hydrogen peroxide, may be used to remove iodine. Likewise a reducing agent such as a reducing sugar, ascorbate, sodium sulfite, etc., may be added to eliminate the last traces of iodine and peroxide.

Reducing sugars, ascorbic acid (Vitamin C) and its salts, and sodium sulfite are well-known, readily available reducing agents that are physiologically acceptable. However, any reducing agents that may be safely ingested and which are innocuous or palatable may be used.

The invention is embodied in a method of disinfecting foods, either liquid or solid with starch-iodine-hydrogen peroxide to provide from a concentration of 0.1 ^w/o to 10^w/o (or higher) starch-iodine-hydrogen peroxide in or on εtrπh foodstuffs.

Description of the Preferred Embodiments Starch-iodine-hydrogen peroxide may be prepared in any of a large number of methods. Substantially pure starch, that may have traces of other biological materials or be essentially free of contaminants is available commercially. Starch, amylose and amylopectin, components of starch and equivalent polysaccharides, encompassed in the term "starch" as used in the general sense indicated above, are also available in high purity. The chemistry of starch and polysaccharides generally is well-developed and a large number of high purity starch and polysaccharide compositions are available commercially. Vapor phase amylose iodine hydrogen peroxide may be produced by a simple variation of the Minto process, U.S. Patent 2,540,486, adding hydrogen peroxide contemporaneously with, before or after the addition of iodine. The term "pure," and its derivatives are used in the sense commonly used in reference to biologically isolates that inherently contain some biologicals other than the principal constituent. Trace amounts of other materials is not per se detrimental to the present invention, and can be tolerated unless they interfere with the iodine-starch reaction or reaction of iodine with microbes. When iodide, e.g. Nal or KI, solutions are added to starch or starch solutions of high starch concentration, the iodide tends to become associated with the starch and appears to cause the starch to form larger particles by crystallization or cross-linking. The addition of hydrogen peroxide, in solution or as a gas, results in starch-iodine-hydrogen peroxide by oxidation of the iodide which, along with the hydrogen peroxide binds to the starch. Starch may be reacted first with hydrogen peroxide followed by reaction of iodide salt or iodine, both resulting direct coupling of the peroxide and iodine to the amylose component of the starch. Reactions may be carried out in solution or by gas phase reaction of hydrogen peroxide and iodine with starch. Ratios of iodine and hydrogen peroxide can be controlled. For example, iodine equivalent to 5 weight percent of the starch may be reacted with the starch either as iodide or iodine. Hydrogen peroxide, in excess of the reactable amount, is then reacted with the starch-iodine, resulting in 5w/o iodine in starch saturated with hydrogen peroxide.

There is a distinct synergism as to the biocidal power of starch-iodine- hydrogen peroxide. The iodine, it is believed, acts most directly on micro¬ organisms, being converted to iodide. The iodide is then converted to iodine by the peroxide, and again kills the microorganisms. The hydrogen peroxide is also biocidal directly, but is believed to be very much less of a factor than the iodine. It has been discovered, however, that starch-iodine-hydrogen peroxide is more effective biocidally that either starch iodine or starch hydrogen peroxide alone, having comparable amounts of iodine and hydrogen peroxide, respectively, in the starch. The synergism is believed to make it possible, in accordance with this invention, to sterilized liquid and solid foodstuffs without significantly degrading the quality or altering the taste of such foodstuffs.

The starch-iodine-hydrogen peroxide may be water soluble or water insoluble. Water soluble starch-iodine-hydrogen peroxide is best formed in solution. Water insoluble starch-iodine-hydrogen peroxide is best formed in very high concentration solutions or suspensions of starch or with starch and added moisture.

The use of starch-I-H₂O₂ and a physiologically acceptable iodine absorbent material, e.g.,solid albumin, solid starch, or cross-linked povidone, to remove residual iodine from liquid foods is within the scope of the invention.

Starch-I-H₂O₂ may comprise, for example, from about 0.01 to 10 weight percent, preferably from 0.1 ^w/o to 10^w/o of the liquid food or the wash or infusing solution. The starch-I-H₂O₂ is allowed to remain in contact with the foods, either liquid or solid, for a period of at least about a half a minute sufficient to kill the microbes, but not long enough to denature or otherwise injure the food. Usually, contact of under an hour is preferred. In some cases, it may be advantageous to leave residual iodine in or on the foodstuff during processing, packaging and subsequent handling. Accordingly, the contact times will be referred to as from one-half minute to one hour with the caveat that longer contact is not usually necessary or beneficial and may result in injury to the food being treated, but would, nevertheless, be within the scope of the invention. The foodstuff is then, in one preferred embodiment, contacted with an iodine absorbing reagent such as cross-linked PVP, or coagulated albumin or solid starch, to remove the iodine. If desired, a reducing agent may thereafter be added in an amount to reduce any iodine that may not have been absorbed. The contact with the iodine absorbing material is preferably accomplished by passing the material undergoing treatment through a layer, i.e. a bed or filter, of solid, substantially insoluble albumin or starch. A second treatment as described may be performed to assure total sterilization, if desired.

In a similar manner, the "addition" of a reducing agent to the material undergoing treatment may be accomplished by passing the liquid foodstuff through a layer of substantially insoluble material that has active reducing sites thereon or equilibrates with the liquid foodstuff undergoing treatment to partially dissolve into such liquid, or make readily available in said liquid (as by swelling, for example) reducing moieties. A bed of beads or fibers, for example, that expose on the surface thereof reducing sugar moieties may be used very conveniently. Long or short columns, formed of one or several iodine-hydrogen peroxide donor materials, with or without iodine or hydrogen peroxide reducing or absorbing materials or filters of such materials may be used in the treatment of liquid foodstuffs. The column or layers just described may be supported by a frit, a filter paper or a porous layer or body of any kind. Any of the beds may be made up the active material, e.g. starch-I-H₂O₂, reducing sugar, etc., attached to carrier particles, such as ground glass, charcoal, ion exchange resin, cellulose derivatives, etc. The paniculate matter may, in a preferred form, consist essentially of particles having a diameter of from about 10 to about 100 microns, but any size that permits suitable flow rates and assures intimate contact may be used.

The use of starch-I-H₂O₂ and a physiologically acceptable reducing agent for treating foodstuffs is a contemplated within this invention. Meats of any kind, processed or unprocessed, may be infused, under pressure or by evacuation before infusion with a starch-I-H₂O₂ solution having concentration of from about 0.01 to 10 weight percent, preferably 0.1 ^w/o to 10^w/o, and thereafter, if desired, treated with the reducing agent to reduce the residual iodine. Meats may also be soaked in such- a solution and thereafter soaked in a solution of a physiologically acceptable and palatable or removable iodine reducing agent.

The use of this invention is expected to obviate the need to add sodium nitrite — a foreign substance to which many people react adversely — during meat processing. The perfusion solution comprises starch-I-H₂O₂ in a concentration of from about 0.01 to 10 weight percent, preferably 0.1 ^w/o to about 10^w/o (100 to 5000 ppm I₂), preferably from about 0.25^w/o to about 2^w/o. After a period of time, most of the unreacted starch-I-H₂O₂ is Washed away and any residual iodine is absorbed into the protein or converted to inactive iodides, e.g. using ascorbate or other reducing agent as described. Some or all residual solution may be allowed to remain in the product as it is packed, shipped and displayed in the market. Since extremely few individuals have any adverse reaction to iodine, the inventive process may provide meat products that can safely be eaten by more of the consuming public that presently is the case. The above applications in which the material to be purified is a liquid can be carried out by flowing the liquid through a bed (e.g. the conventional filter structure of solid particles on a porous or foraminous support) of solid particles of starch-I-H₂O₂ of suitable size or by contacting the liquid with particles or a membrane or surface of solid starch-I-H₂O₂. In carrying out this facet of the invention, the liquid is contacted with the solid starch-I-H₂O₂. This may be done most efficiently, in most cases, by passing the liquid through a settled or fluidized or packed bed of starch-I-H₂O₂ particles or passing the liquid over a surface of the starch-I-H₂O₂ material, e.g. over a multiple-plate anay of sheets of such material. The starch-I-H₂O₂ may be washed and the iodine content therein regenerated between uses.

Iodine and iodides may be removed in a similar manner by passing the liquid through a solid or fluidized bed of starch particles, the term starch being used here to include derivatives, amylose, etc., which are initially free of or contain far less than saturation amounts of iodine and iodides. The bed absorbs the iodine and iodides purifying the liquid.

In general a solution of reducing agent , e.g. a reducing sugar (or mixtures of reducing sugars), ascorbic acid or ascorbate, a sulfite, e.g. sodium sulfite, etc. in which the agent is in a concentration of 0.001 to 1 percent is suitable and such is implicit unless otherwise noted.

Solvent extraction of iodine with a solvent for iodine that is substantially inert to foods, either liquid or solid, generally may also be used to remove iodine. N-heptane is a good solvent for iodine and has minimal effect, on short exposure, to biological materials. Close n-alkane analogues and vegetable oils may also be used. Cotton seed oil, corn oil, etc. are generally biologically inert and are also suitable solvents for iodine. The solvent extraction may be carried out in any suitable vessel that will permit intimate mixing of the liquid and extractant-solvent and decantation of the hydrophobic phase from the top or withdrawal of the liquid from the bottom.

Industrial Application This invention finds application in agriculture, fermentation industries, food and beverage preparation industries.

Claims

WHAT IS CLAIMED IS:

1. The use of starch-I-H₂O₂ for the manufacture of a liquid foodstuff, the starch-I-H₂O₂ being added in an amount in excess of that required to kill or inactivate all microbes therein comprising from about 0.01^w/o to about 10^w/o of the liquid foodstuff.

2. The invention of Claim 1 further comprising thereafter adding an edible reducing agent to reduce the residual iodine.

3. The invention of Claim 1 further comprising treating the foodstuff with starch that contains less than saturation amounts of iodine and iodide to remove iodine and iodide from the foodstuff.

4. The invention of Claim 1 further comprising thereafter extracting residual iodine from the liquid foodstuff with a solvent for iodine that is not detrimental to the quality of the liquid foodstuff.

5. The use of starch-I-H₂O₂ for the manufacture of a processed solid foodstuff, the starch-I-H₂O₂ being infused into the solid foodstuff in an amount in excess of that required to kill or inactivate all microbes therein comprising from about 0.0 r/o to about 10^w/o of the foodstuff.

6. The invention of Claim 5 further comprising thereafter infusing the foodstuff with an edible reducing agent to reduce the residual iodine.

7. The invention of Claim 5 further comprising thereafter extracting residual iodine from the foodstuff with a solvent for iodine that is not detrimental to the quality of the foodstuff.

8. A method for treating a liquid foodstuff to kill microbes therein comprising passing said liquid foodstuff into at least one bed or column of particulate matter comprising substantially insoluble starch-I-H₂O₂, said bed or column being so formed and configured as to permit the passage of the liquid foodstuff therethrough in intimate contact with the surfaces of the particles forming the bed or particle.

9. The method of Claim 8 further comprising adding an edible reducing agent to the liquid foodstuff to reduce residual iodine.

10. The method of Claim 9 further comprising passing the liquid foodstuff into intimate contact with a solid iodine absorbing material to remove rea. ual iodine.

11. The method of Claim 8 further comprising solvent extracting iodine frαiϊ. the liquid foodstuff with a solvent that does not degrade the quality of the liquid foodstuff.

12. A method for treating a permeable solid foodstuff to kill microbes therein comprising infusing said solid foodstuff with a solution of starch-I-H₂O₂ sufficient to permit the passage of said solution therethrough.

13. The method of Claim 12 further comprising infusing the solid foodstuff with an edible reducing agent to reduce residual iodine.

14. The method of Claim 13 further comprising solvent extracting iodine from the foodstuff with a physiologically acceptable solvent that does not degrade the quality of the foodstuff.

15. A method for treating meat intended for human consumption to kill microbes therein comprising infusing said meat with a solution of starch-I-H₂O₂ sufficient to permit the passage of said solution therethrough.

16. The method of Claim 15 further comprising infusing the meat with an edible reducing agent to reduce residual iodine.

17. The method of Claim 15 further comprising solvent extracting iodine from the meat with a physiologically acceptable solvent that does not substantially degrade the palatability of the meat.

18. A method for treating solid foodstuff to kill microbes therein comprising washing said solid foodstuff with a solution of starch-I-H₂O₂ sufficient to permit contact of all surfaces of the foodstuff by said solution.

19. The method of Claim 18 further comprising washing the solid foodstuff with an edible reducing agent to reduce residual iodine.

20. The method of Claim 19 further comprising solvent extracting iodine from the foodstuff with a physiologically acceptable solvent that does not degrade the quality of the foodstuff.