Method for cleaning and disinfection

Abstract

This invention relates to cleaning and disinfection of apples and pears through the feed of aqueous blends of select disinfectant chemicals and select cleaning chemicals to provide simultaneous cleaning and sanitation on produce and food processing surfaces.

Claims

1. A method for cleaning and disinfecting apples and pears in a fresh packing process, in which at least one disinfectant chemical and at least one cleaning chemical are fed into a flowing water line, or storage tank, to create a blended treated water containing a desired dose of the at least one disinfectant chemical and the at least one cleaning chemical within the treated water, said treated water then being directed to one or more distinct feed points along the apple or pear fresh pack processing line and delivered onto the produce and the food contact surfaces associated with that line, wherein the disinfectant chemical consists of chlorine dioxide, a quaternary ammonium compound, or peroxyacetic acid.

2. A method according to claim 1 in which the cleaning chemical can be selected from the groups consisting of: an acidic formulation, consisting of chemicals such as citric acid, phosphoric acid, EDTA (Ethylene diamine tetraacetic acid), DDBSA (dodecylbenzenesulfonic acid), or other acid-based surfactant chemicals, and mixtures thereof. an alkaline formulation, consisting of chemicals such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, sodium metasilicate, sodium tripolyphosphate, sodium dodecylbenzene sulfonate, and other alkaline-based surfactant chemicals, and mixtures thereof. a neutral formulation, consisting of surfactants such as ethoxylated secondary alcohols (C11-15) (called Fruit & Vegetable Kleen 340 from DECOO), polysorbates (called Tween and Span), oligomeric alkypoly(ethyleneoxides) (called Brij and Tergitol), and other neutral surfactant chemicals, and mixtures thereof.

3. A method according to claim 1 in which at least one additional disinfectant chemical is fed into a flowing water line, or storage tank, wherein the additional disinfectant chemical is selected from the group consisting of peroxyacetic acid, sodium hypochlorite, calcium hypochlorite, BCDMH (bromo-chloro-dimethylhydantoin) iodine, and quaternary ammonium compounds.

4. A method according to claim 1 in which quaternary ammonium compounds that are effective antimicrobials within the scope of this invention are selected from the group consisting of benzalkonium chloride, benzethonium chloride, methylbenzethonium chloride, cetalkonium chloride, cetylpyridinium chloride, cetrimonium, cetrimide, dofanium chloride, tetraethylammonium bromide, didecyldimethylammonium chloride, domiphen bromide, and other similar quaternary ammonium compounds, especially those containing long alkyl chains.

5. A method for cleaning and disinfecting apples and pears in a fresh packing process, in which sodium chlorite, peroxyacetic acid, and at least one cleaning chemical are fed into a flowing water line, or storage tank, to create a blended treated water containing a desired dose of the sodium chlorite, peroxyacetic acid, and the at least one cleaning chemical within the treated water, said treated water then being directed to one or more distinct feed points along the apple or pear fresh pack processing line and delivered onto the produce and the food contact surfaces associated with that line.

6. A method according to claim 5 in which the cleaning chemical can be selected from the groups consisting of: an acidic formulation, consisting of chemicals such as citric acid, phosphoric acid, EDTA (Ethylene diamine tetraacetic acid), DDBSA (dodecylbenzenesulfonic acid), or other acid-based surfactant chemicals, and mixtures thereof. an alkaline formulation, consisting of chemicals such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, sodium metasilicate, sodium tripolyphosphate, sodium dodecylbenzene sulfonate, and other alkaline-based surfactant chemicals, and mixtures thereof. a neutral formulation, consisting of surfactants such as ethoxylated secondary alcohols (C11-15) (called Fruit & Vegetable Kleen 340 from DECOO), polysorbates (called Tween and Span), oligomeric alkypoly(ethyleneoxides) (called Brij and Tergitol), and other neutral surfactant chemicals, and mixtures thereof.

7. A method for cleaning and disinfecting apples and pears in a fresh packing process, in which sodium chlorite and at least one acidic cleaning chemical are fed into a flowing water line, or storage tank, to create a blended treated water containing a desired dose of the sodium chlorite and the at least one acidic cleaning chemical within the treated water, said treated water then being directed to one or more distinct feed points along the apple or pear fresh pack processing line and delivered onto the produce and the food contact surfaces associated with that line, wherein the acidic cleaning chemical can be a formulation consisting of chemicals such as citric acid, phosphoric acid, EDTA (Ethylene diamine tetraacetic acid), DDBSA (dodecylbenzenesulfonic acid), or other acid-based surfactant chemicals, and mixtures thereof.

8. A method for cleaning and disinfecting apples and pears in a fresh packing process, in which sodium chlorite, a quaternary ammonium compound, and at least one acidic cleaning chemical are fed into a flowing water line, or storage tank, to create a blended treated water containing a desired dose of the sodium chlorite, quaternary ammonium compound, and the at least one acidic cleaning chemical within the treated water, said treated water then being directed to one or more distinct feed points along the apple or pear fresh pack processing line and delivered onto the produce and the food contact surfaces associated with that line, wherein the acidic cleaning chemical can be a formulation consisting of chemicals such as citric acid, phosphoric acid, EDTA (Ethylene diamine tetraacetic acid), DDBSA (dodecylbenzenesulfonic acid), or other acid-based surfactant chemicals, and mixtures thereof.

9. A method for cleaning and disinfecting apples and pears in a fresh packing process, in which chlorine dioxide, a quaternary ammonium compound, and at least one cleaning chemical are fed into a flowing water line, or storage tank, to create a blended treated water containing a desired dose of the chlorine dioxide, quaternary ammonium compound, and the at least one cleaning chemical within the treated water, said treated water then being directed to one or more distinct feed points along the apple or pear fresh pack processing line and delivered onto the produce and the food contact surfaces associated with that line.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0020] This invention relates to a method of blending cleaning and disinfection chemicals prior to an application point, thus benefiting from the activity of such blends for improved cleaning and sanitation of microbiologically contaminated surfaces. More specifically, this invention relates to a method for the simultaneous cleaning and disinfection of apples and pears, and the fresh packing equipment surfaces that they pass over, which comprises adding a blend of a disinfecting chemical and a cleaning chemical directly to the fruit as it passes along the packing line surfaces. While the description of the activity of the aqueous blends of disinfecting chemicals and cleaning chemicals is predominantly focused on the apple and pear packing processes, it should be recognized that the benefits of application of these aqueous blends of disinfecting chemicals and cleaning chemicals can be realized in other food processing applications.

[0021] Not every disinfectant can be blended with every cleaner. Many disinfectants are strong oxidizing agents, such as chlorine which reacts with known commercially available FDA-approved surfactant chemicals to cause destruction of the disinfectant and a reduction in the available surfactant chemical useful for cleaning. Various forms of chlorine, such as Cl.sub.2, NaOCl, Ca(OCl).sub.2, and others, react with organic molecules to generate toxic chlorinated by-products called THMs (trihalomethanes) and HAAs (halogenated acetic acid). It is the goal of this invention for the selected disinfectant to have a minimal reactivity with the cleaning chemical, so that the maximum effect of the disinfectant will be directed toward reducing microbiological contamination in the fruit and packing line surfaces that it encounters.

[0022] Some disinfectants, such as hydrogen peroxide, do not possess the necessary reactivity to provide effective antimicrobial performance in the short amount of time afforded in the soapy section of the apple packing brush bed. Therefore, thoughtful consideration is needed to identify select disinfectants and select cleaning chemicals for optimal antimicrobial reactivity and stability properties in order to achieve the desired results for optimal cleaning and sanitation.

[0023] There are many occasions in the processing and packing of fresh apples and pears when the fruit coming in from the orchard is coated with a layer of mineral scale (i.e., calcium carbonate). This occurs in orchards that use overhead spray irrigation to cool the apples (minimizing the effects of sunburn) as well as to water the tree. When the water on the fruit dries, it can leave behind a coating of scale. Therefore, under such conditions, it is common for the apple or pear packing facility to apply a cleaning chemical to the fruit as they are being polished on the brush bed that has an acidic formulation, consisting of chemicals such as citric acid, phosphoric acid, EDTA (Ethylene diamine tetraacetic acid), DDBSA (dodecylbenzenesulfonic acid), or other acid-based surfactant chemicals, and mixtures thereof.

[0024] Under other conditions, such as when there is a need to remove the existing natural wax coating on an apple, the desired cleaning chemical is one with an alkaline formulation, consisting of chemicals such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, sodium metasilicate, sodium tripolyphosphate, sodium dodecylbenzene sulfonate, and other alkaline-based surfactant chemicals, and mixtures thereof.

[0025] Under still other conditions, the desired cleaning chemical is one with a neutral formulation, consisting of surfactants such as ethoxylated secondary alcohols (C11-15) (called Fruit & Vegetable Kleen 340 from DECOO), polysorbates (called Tween and Span), oligomeric alkypoly(ethyleneoxides) (called Brij and Tergitol), and other neutral surfactant chemicals, and mixtures thereof.

[0026] The selection of cleaning chemical formulations for the various cleaning purposes associated with this application is within the known skilled art of the apple and pear fresh packing industry. However, the proper selection of the disinfectant to be blended with each possible cleaning chemical formulation is not well known in the art. In general, selection of a disinfectant chemical that is a weaker oxidizing agent than other possible disinfectants is preferred. For this reason, sodium chlorite and chlorine dioxide, which are weaker oxidizing agents than other disinfectants, such as ozone, hydrogen peroxide, and chlorine (bleach), are the most preferred disinfectants for the purpose of maximizing the overall benefits from being blended with the desired cleaning chemical prior to being applied to a food or food processing surface.

[0027] More specifically, this application teaches a method for cleaning and disinfecting apples and pears in a fresh packing process, in which at least one disinfectant chemical and at least one cleaning chemical are fed into a flowing water line, or storage tank, to create a blended treated water containing a desired dose of the disinfectant chemical and the at least one cleaning chemical within the treated water, said treated water then being directed to one or more distinct feed points along the apple or pear fresh pack processing line and delivered onto the produce and the food contact surfaces associated with that line, wherein the disinfectant chemical consists of sodium chlorite or chlorine dioxide.

[0028] The cleaning chemical can be selected from a broad range of potential cleaning chemicals, most specifically from the groups consisting of: [0029] an acidic formulation, consisting of chemicals such as citric acid, phosphoric acid, EDTA (Ethylene diamine tetraacetic acid), DDBSA (dodecylbenzenesulfonic acid), or other acid-based surfactant chemicals, and mixtures thereof. [0030] an alkaline formulation, consisting of chemicals such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, sodium metasilicate, sodium tripolyphosphate, sodium dodecylbenzene sulfonate, and other alkaline-based surfactant chemicals, and mixtures thereof. [0031] a neutral formulation, consisting of surfactants such as ethoxylated secondary alcohols (C11-15) (called Fruit & Vegetable Kleen 340 from DECOO), polysorbates (called Tween and Span), oligomeric alkypoly(ethyleneoxides) (called Brij and Tergitol), and other neutral surfactant chemicals, and mixtures thereof.

[0032] Within the scope of this application, the method can be expanded to include the further blending of at least one additional disinfectant chemical into the treated flowing water line, or storage tank, wherein the additional disinfectant chemical is selected from the group consisting of peroxyacetic acid, sodium hypochlorite, calcium hypochlorite, BCDMH (bromo-chloro-dimethylhydantoin), iodine, and quatemary ammonium compounds.

[0033] In like fashion, this method for cleaning and disinfecting apples and pears in a fresh packing process can be employed in which the selected disinfectant is a quaternary ammonium compound, to be blended with at least one cleaning chemical and fed into a flowing water line, or storage tank, to create a blended treated water containing a desired dose of the quaternary ammonium compound and the at least one cleaning chemical within the treated water, said treated water then being directed to one or more distinct feed points along the apple or pear fresh pack processing line and delivered onto the produce and the food contact surfaces associated with that line.

[0034] Quaternary ammonium compounds that are effective antimicrobials within the scope of this invention are selected from the group consisting of benzalkonium chloride, benzethonium chloride, methylbenzethonium chloride, cetalkonium chloride, cetylpyridinium chloride, cetrimonium, cetrimide, dofanium chloride, tetraethylammonium bromide, didecyldimethylammonium chloride, domiphen bromide, and other similar quaternary ammonium compounds, especially those containing long alkyl chains.

[0035] There are certain highly effective applications of this method that involve the blending of two disinfectants along with at least one cleaning chemical formulation. One such method for cleaning and disinfecting apples and pears in a fresh packing process involves the blending of sodium chlorite, peroxyacetic acid, and at least one cleaning chemical into a flowing water line, or storage tank, to create a blended treated water containing a desired dose of the sodium chlorite, peroxyacetic acid, and the at least one cleaning chemical within the treated water, said treated water then being directed to one or more distinct feed points along the apple or pear fresh pack processing line and delivered onto the produce and the food contact surfaces associated with that line. In this method, the acidity of the PAA facilitates the transformation of chlorite into chlorine dioxide (ClO.sub.2), which is a highly potent disinfectant even at very low dosages. For this application of the blend of sodium chlorite and PAA, the cleaning chemical can be selected from the groups consisting of: [0036] an acidic formulation, consisting of chemicals such as citric acid, phosphoric acid, EDTA (Ethylene diamine tetraacetic acid), DDBSA (dodecylbenzenesulfonic acid), or other acid-based surfactant chemicals, and mixtures thereof. [0037] a neutral formulation, consisting of surfactants such as ethoxylated secondary alcohols (C11-15) (called Fruit & Vegetable Kleen 340 from DECOO), polysorbates (called Tween and Span), oligomeric alkypoly(ethyleneoxides) (called Brij and Tergitol), and other neutral surfactant chemicals, and mixtures thereof. [0038] Another method for cleaning and disinfecting apples and pears in a fresh packing process involves the blending of sodium chlorite, a quaternary ammonium compound, and at least one acidic cleaning chemical into a flowing water line, or storage tank, to create a blended treated water containing a desired dose of the sodium chlorite, a quaternary ammonium compound, and the at least one acidic cleaning chemical within the treated water, said treated water then being directed to one or more distinct feed points along the apple or pear fresh pack processing line and delivered onto the produce and the food contact surfaces associated with that line. In this method, the acidity of the cleaning chemical facilitates the transformation of chlorite into chlorine dioxide (ClO.sub.2). For this application of the blend of sodium chlorite and a quaternary ammonium compound, the acidic cleaning chemical can be selected from the groups consisting of citric acid, phosphoric acid, EDTA (Ethylene diamine tetraacetic acid), DDBSA (dodecylbenzenesulfonic acid), or other acid-based surfactant chemicals, and mixtures thereof.

[0039] Still another method for cleaning and disinfecting apples and pears in a fresh packing process involves the blending of chlorine dioxide (ClO.sub.2), a quaternary ammonium compound, and at least one cleaning chemical into a flowing water line, or storage tank, to create a blended treated water containing a desired dose of the ClO.sub.2, a quatemary ammonium compound, and the at least one cleaning chemical within the treated water, said treated water then being directed to one or more distinct feed points along the apple or pear fresh pack processing line and delivered onto the produce and the food contact surfaces associated with that line. In this method, the cleaning chemical can be selected from the groups consisting of: [0040] an acidic formulation, consisting of chemicals such as citric acid, phosphoric acid, EDTA (Ethylene diamine tetraacetic acid), DDBSA (dodecylbenzenesulfonic acid), or other acid-based surfactant chemicals, and mixtures thereof. [0041] an alkaline formulation, consisting of chemicals such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, sodium metasilicate, sodium tripolyphosphate, sodium dodecylbenzene sulfonate, and other alkaline-based surfactant chemicals, and mixtures thereof. [0042] a neutral formulation, consisting of surfactants such as ethoxylated secondary alcohols (C11-15) (called Fruit & Vegetable Kleen 340 from DECOO), polysorbates (called Tween and Span), oligomeric alkypoly(ethyleneoxides) (called Brij and Tergitol), and other neutral surfactant chemicals, and mixtures thereof.

Examples

[0043] The following examples employ blends of disinfectants with specific food grade cleaners from a company called DECCO (DECCO US Post-Harvest, Inc., 1713 S. California Ave. Monrovia, Calif. 91016). However, cleaner formulas, surfactant formulas, and detergent formulas from other manufacturers/distributors, such as Ecolab (370 Wabasha St N, Saint Paul, Minn. 55102), Pace International (5661 Branch Rd, Wapato, Wash. 98951), or Wesmar Company (5720 204th St SW, Lynnwood, Wash. 98036), could have equally been selected for such examples. In addition, these examples highlight various blends with sodium chlorite and chlorine dioxide with PAA; however, similar blends can be formulated with these same cleaning products by replacing PAA with a quaternary ammonium compound. [0044] 1. Disinfectant blended with an acidic cleaner from DECCOKLEEN PAC AC (which contains a blend of sulfonic acid and citric acid): Chlorine Dioxide+KLEEN PAC AC Sodium Chlorite+KLEEN PAC AC [0045] 2. Two disinfectants blended with an acidic cleaner from DECCOKLEEN PAC AC (which contains a blend of sulfonic acid and citric acid): Chlorine Dioxide+Peroxyacetic Acid+KLEEN PAC AC Sodium Chlorite+Peroxyacetic Acid+KLEEN PAC AC [0046] 3. Disinfectant blended with a different acidic cleaner from DECCO APL-KLEEN.fwdarw.246 (which contains a blend of phospshoric acid, DDBSA, and propylene glycol blend): Chlorine Dioxide+APL-KLEEN.fwdarw.246 Sodium Chlorite+APL-KLEEN.fwdarw.246 [0047] 4. Two disinfectants blended with a different acidic cleaner from DECCO APL-KLEEN.fwdarw.246 (which contains a blend of phospshoric acid, DDBSA, and propylene glycol blend): Chlorine Dioxide+Peroxyacetic Acid+APL-KLEEN.fwdarw.246 Sodium Chlorite+Peroxyacetic Acid+APL-KLEEN.fwdarw.246 [0048] 5. Disinfectant blended with an alkaline cleaner from DECCO FRUIT & VEGETABLE KLEEN.fwdarw.241 (which contains sodium dodecylbenzene sulfonate): Chlorine Dioxide+FRUIT & VEGETABLE KLEEN.fwdarw.241 [0049] 6. Two disinfectants blended with an alkaline cleaner from DECCO FRUIT & VEGETABLE KLEEN.fwdarw.241 (which contains sodium dodecylbenzene sulfonate): Chlorine Dioxide+Peroxyacetic Acid+FRUIT & VEGETABLE KLEEN.fwdarw.241

[0050] Etc.

[0051] Food-grade cleaning chemicals were selected from DECCO simply because the DECCO website provided the chemical compositional information in the formulations to allow for best understanding of the successful blending of these cleaners with select disinfectants. Therefore, the choice to use cleaners from DECCO in the above examples is not intended to limit in any way the blending of select disinfectants with other cleaning chemicals from other sanitation companies, such as Ecolab, Pace International, or Wesmar Company, or any other company that provides an approved food-grade cleaner or soap or detergent or surfactant chemical or similar formulation for the food processing market, and, more specifically, for the apple and pear packing market.

[0052] Note that Examples #1 through #4 describe blends of sodium chlorite with acidic cleaners, while in Examples #5 and #6 there was no mention of a blend of sodium chlorite with the alkaline cleaner. When an acidic cleaner is being used, as in Examples #1 through #4, the pH of the aqueous environment that is present on the food processing equipment will be acidic. In an acidic environment, for instance the environment created between the bristles of an apple packing brush bed treated with an acidic soap, the chemical conversion of sodium chlorite into chlorine dioxide (ClO.sub.2) occurs in-situ, resulting in the generation of ClO.sub.2 within the aqueous soap mixture entrained within the brush bed bristles. Likewise, though to a lesser extent, when a pH neutral cleaner is being used, the natural acidity of the produce (for instance, apples) will result in a slightly acidic environment that will also foster the generation of ClO.sub.2 from the feed of sodium chlorite. The flowing chemical equation describes the reaction between sodium chlorite (NaClO.sub.2) and an acid (shown as the hydrogen cation, H*):

5NaClO.sub.2+4H.sup.+.fwdarw.NaCl+4ClO.sub.2+2H.sub.2O+4Na.sup.+

[0053] The use of various acids to generate chlorine dioxide from sodium chlorite is well known in the chemical and medicinal field. For instance, using hydrochloric acid (HCl) results in the following chemical equation:

5NaClO.sub.2+4HCl.fwdarw.5NaCl+4ClO.sub.2+2H.sub.2O

[0054] Other inventive blends include those in which sodium chlorite can be blended into the spray bar rinse water line with peroxyacetic acid (PAA) and an acidic cleaner, in which the acidity of the PAA and the acidic cleaner will convert the sodium chlorite into chlorine dioxide as the entire mixture resides in contact with the produce and food processing equipment, and, more specifically, within the bristles of an apple or pear packing line brush bed.

[0055] Other inventive blends include those in which sodium chlorite can be blended into the spray bar rinse water line with a quaternary ammonium sanitizer and an acidic cleaner.

[0056] Still other inventive blends include those in which chlorine dioxide can be blended into the spray bar rinse water line with a quaternary ammonium sanitizer and an alkaline cleaner.

[0057] Another inventive blend includes those in which chlorine dioxide can be blended into the spray bar rinse water line with peroxyacetic acid (PAA) and an alkaline cleaner.

[0058] How the Invention Works:

[0059] In its simplest form, the invention works by feeding an aqueous stream of a disinfectant chemical into an aqueous stream of a cleaning chemical, blending them together into a single aqueous stream, or storage tank, that is then fed to one or more food processing surfaces containing produce. More specifically for the apple and pear fresh packing industry, the invention works by feeding the blended stream of disinfectant and cleaner to a spray bar, drip bar, rain pan, water curtain, or flood box, introducing this aqueous blended treatment simultaneously to the fruit, brush bed, and associated food processing equipment along the brush bed section of an apple or pear packing line. Depending on the length of the soap section of the brush bed, two or more application points (spray bar, drip bar, rain pan, or flood box) can be added. The primary mechanism for blending the disinfectant and cleaner is via chemical metering pumps.

[0060] Incorporating a second disinfectant into the already blended mixture that contains a first disinfectant and the cleaning chemical can simply involve feeding an aqueous stream of the second disinfectant, via a separate chemical metering pump, into the single aqueous stream already containing the first disinfectant and the cleaner. Alternatively, the second disinfectant can be fed into the aqueous stream containing the cleaner at a point prior to that of where the first disinfectant is being fedi.e., order of addition of the disinfectants is not important for changing or optimizing product performance. Finally, one of the two disinfectants can be fed into the water line prior to the addition of the cleaner, which can then be followed by addition of the second disinfectanti.e., order of addition of the cleaner and disinfectants is not important for changing or optimizing performance.

[0061] In the actual application of this invention, the primary method for chemical delivery is via metering pumps set at the proper feed rate of each chemical additive (disinfectant or cleaner) in order to deliver the necessary concentrations of each additive into the single blended water stream to achieve optimum cleaning and disinfection performance. As a secondary method for chemical delivery, the cleaner and disinfectant chemicals can be fed into a flowing water line using an eductor (venturi) to create the blended stream. Finally, a third method for chemical delivery is to feed the necessary amount of each cleaner and disinfectant into a water storage tank and then pumping this treated water to the desired feed point(s). However, due to the increased contact time within the storage tank, care must be taken to ensure that the disinfectant and cleaner chemicals do not react with each other in the storage tank, thus reducing the performance activity of each component in the blend prior to being fed to the brush bed or other sections of the processing line.

[0062] For cases in which chlorine dioxide is used as a disinfectant, the on-site generation of chlorine dioxide can be performed using one of any number of well-known methods, such as: [0063] reducing sodium chlorate in a strong acid solution with a suitable reducing agent such as methanol or hydrogen peroxide (predominantly used for pulp bleaching). [0064] using a three-chem method of blending sodium chlorite, sodium hypochlorite, and hydrochloric acid:

2NaClO.sub.2+2HCl+NaOCl.fwdarw.2ClO.sub.2+3NaCl+H.sub.2O [0065] using a two-chem method of blending sodium chlorite with an acid, such as hydrochloric acid:

5NaClO.sub.2+4HCl.fwdarw.5NaCl+4ClO.sub.2+2H.sub.2O [0066] using an electrolytic one-chem method involving electrolysis of a chlorite solution:

2NaClO.sub.2+2H.sub.2O.fwdarw.2ClO.sub.2+2NaOH+H.sub.2

[0067] In the case where an electrolytic one-chem method is employed for ClO.sub.2 generation, this method produces two product streams, one containing ClO.sub.2 and the other containing sodium hydroxide (NaOH). The stream containing ClO.sub.2 will be used as the disinfectant stream. The stream that contains NaOH can be fed into the soap line for those instances when an alkaline cleaner is being employed. Otherwise, it can be fed to the drain.

[0068] There are many reports of the limited and selective reaction chemistry of chlorine dioxide with organic molecules, some of which are referenced below: [0069] C. Rav-Acha, The Reactions of Chlorine Dioxide with Aquatic Organic Materials and Their Health Effects, Water Res., 18 (11), 84, 1984. [0070] W. J. Masschelein, The State of Art in the Use of Chlorine Dioxide and Ozone in the Treatment of Water, Water SA, 6(3), 116-129, 1980. [0071] M. G. Noak, and R. L. Doerr, Chlorine Oxygen Acids and SaltsChlorine Dioxide, Chlorous Acid, and Chlorites, Kirk-Othmer Encycl. Chem. Technol., 3rd Ed., Volume 5, 612-632, 1979.

[0072] For instance, sodium hypochlorite reacts with ammonia or amines, while chlorine dioxide reacts very slowly with secondary amines, and not at all with primary amines or ammonia. Finally, while chlorine and bromine react with organic molecules to primarily attached a chlorine or bromine atom to the organic molecule, resulting in the formation of a toxic halogenated hydrocarbon, chlorine dioxide primarily reacts via an oxidation mechanism in which the oxygen atom from ClO.sub.2 is added to the organic molecule, resulting in no increase in toxicity related to disinfection by-products from the use of ClO.sub.2.

[0073] Because of the limited reaction of ClO.sub.2 with organic contaminants, a high percentage of the chlorine dioxide added to the brush bed section of the packing line remains available for an extended period of time as an active antimicrobial agent, and is not rapidly consumed to the degree that chlorine, bromine, PAA, or ozone would be under the same circumstances. Also, when ClO.sub.2 reacts with organic molecules, one of the by-products is chlorite, which is the precursor for the re-generation of ClO.sub.2. Therefore, in the presence of an acidic soapy environment, there will be a cycling of ClO.sub.2 to chlorite and back to ClO.sub.2 that will extend the disinfection performance of ClO.sub.2 farther down the brush bed. For these reasons, sodium chlorite and chlorine dioxide are the preferred disinfectants for this inventive method.

[0074] The actual practice of the invention can be accomplished using chemical metering pumps with individual feed lines connected to each disinfectant chemical and cleaning chemical being employed, with these feed lines being connected to a water line that carries the desired concentrations of the blended disinfectant-cleaner formula to the brush bed feed point (spray bar, drip bar, rain pan, or flood box) or any other application point along the processing line.

[0075] The necessary elements of this invention are the individual chemical storage tanks (drums, IBC totes, bulk tanks, etc.) that hold the disinfectant(s) and cleaning chemical(s), the individual feed lines that connect the disinfectant line(s) and cleaning chemical line(s) to the single water line that delivers the mixture to the desired food processing line application feed points, such as to the brush bed of an apple or pear fresh packing line.

[0076] Optional components are the individual chemical metering pumps for each chemical. Alternatively, eductors (venturi) can be used in lieu of pumps to deliver the appropriate concentrations of chemicals into the water line.

[0077] The order of addition of the disinfectant(s) or cleaner is not important for changing or optimizing product performance, so long as the disinfectant chemical(s) and cleaning chemical are properly mixed at the desired dosage of each component.

[0078] This invention can be used in fruit and vegetable packing applications other than just apple and pear packing, such as in cherry packing, onion packing, potato packing, in washing of leafy greens, kiwis, tomatoes, and in any food processing application that uses rinse water in direct contact with the food product or produce.

[0079] While various embodiments of the invention have been described, as noted above, many changes can be made without departing from the spirit and scope of the invention. Accordingly, the scope of the invention is not limited by the disclosure of the preferred embodiment. Instead, the invention should be determined entirely by reference to the claims that follow.