Drug – bio-affecting and body treating compositions – Plant material or plant extract of undetermined constitution... – Containing or obtained from a flower or blossom
Reexamination Certificate
2000-07-18
2002-04-30
Lankford, Jr., Leon B. (Department: 1651)
Drug, bio-affecting and body treating compositions
Plant material or plant extract of undetermined constitution...
Containing or obtained from a flower or blossom
C424S725000, C424S405000, C424S094100
Reexamination Certificate
active
06379720
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to biocides and, more particularly, to compositions containing hops extract and their use in water systems and process streams to control biological fouling.
BACKGROUND OF THE INVENTION
Growth of microorganisms such as bacteria, fungi and algae, as well as macroorganisms such as mussels and clams, is problematic in water systems and process streams. As used herein, “water systems” is defined to include municipal, commercial and industrial water systems, as well as aqueous streams. The term “aqueous streams” includes, but is not limited to, streams used for transporting or processing food products and on food surfaces and equipment surfaces that come in contact with the aqueous stream. Examples of food products include fruits vegetables and tubers such as tomatoes, potatoes, bananas, apples, beets, and the like, and meats such as poultry, beef and the like and the surfaces thereof. “Process streams,” as used herein includes, but is not limited to, sugar beet diffuser systems.
Proliferation of microorganisms and macroorganisms can cause mechanical, operational and chemical problems with economic and health-related consequences. Similarly, growth of microorganisms in aqueous streams is undesirable. Poor biological control in these systems can cause product spoilage and loss, high water use rates, and the potential for health-related problems.
Many of the chemicals used to control biological fouling in water systems and process streams were developed based on efficacy, without primary emphasis on safety and environmental compatibility. Many of these chemicals are toxic to terrestrial animals or aquatic life, are eye or skin irritants, can produce sensitization reactions with repeated exposure, or have toxic byproducts. There are many naturally-occurring substances with biocidal properties. Natural substances that control microbial fouling have been, to some extent, optimized through evolution and are, by definition, environmentally compatible. Product research and development guided by the use or imitation of natural microbial fouling control substances has the potential to provide useful and innovative water treatment chemistries.
Hops extract is typically produced as an amber colored liquid used primarily for flavor enhancement of beer. Hops extract is obtained from the hop plant (
Humulus lupulus
) as a group of resins, commonly referred to as alpha acids, represented by humulone and its congeners (cohumulone, adhumulone) and beta acids, represented by lupulone and its congeners (colupulone, adlupulone). Beta acid (lupulone) extracts from hops are a product of the brewing process. Hops beta acid extracts are also produced for use in the brewing process to alter properties of the finished beverage. Therefore, abundant sources of raw material for hops extract-based biological control products are available. The fact that hops extract alpha and beta acids are routinely consumed by humans emphasizes the favorable toxicity profile of these substances.
As known in the brewing industry, some hop acids have antimicrobial activity against specific bacteria. For example, U.S. Pat. Nos. 5,082,975 and 5,166,449 disclose that the hop acid hexahydrolupulone inhibits the growth of certain Lactobacillus species. Similarly, U.S. Pat. No. 5,455,038 discloses the use of tetrahydroisohumulone or hexahydrocolupulone to inhibit the growth of Listeria species in food and food packaging materials; U.S. Pat. No. 5,370,863 discloses the use of specific alpha and beta hop acids in oral care compositions for inhibition of microorganisms that cause plaque and periodontal disease; and U.S. Pat. No. 5,286,506 discloses the use of hops extract beta acids to control pathogenic bacteria, such as Listeria, in food.
In general, hops extract is a bacterial inhibitor, not a bactericidal agent. Hops extract has poor efficacy against Gram-negative bacteria which are major slime-producing organisms in many water systems. Hops extract is more effective against Gram-positive bacteria. For example,
Leuconostoc mesenteroides
is a significant problematic microorganism in sugar beet processing and diffuser systems and is a Gram-positive organism which is susceptible to hops extract. Glutaraldehyde and other biocides are currently used in sugar beet diffusion systems to control microbiological fouling due to Leuconostoc and other bacteria. However, none of the biocides currently used in this application, including glutaraldehyde, are as safe as hops extract. The use of hops extract in the sugar industry for microbial control has been previously disclosed (Pollach, et al., Zuckerind. 121 (1996) Nr. 12, S. 919-926; Hein et al., Zuckerind. 122 (1997) Nr. 12, S. 940-949; and Pollach et al., Zuckerind. 124 (1999) Nr. 8, S. 622-637).
Growth of algae can be a problem in any water system exposed to sunlight. Uncontrolled algae growth typically begins as a cosmetic problem, but can lead to problems such as distribution deck plugging and increased halogen demand in cooling towers, and unacceptable water quality in swimming pools, decorative fountain and other water features. Although there are numerous non-oxidizing biocides available for algae control, many of these biocides have high human and environmental toxicity.
Chemistries found naturally or which mimic natural chemical processes are commonly referred to as “green.” As environmental restrictions and regulations governing biocides increase, use of some biocides may be restricted. Therefore, green biocides such hops extract may provide an effective and environmentally sound biocide alternative in water treatment.
Accordingly, it would be desirable to provide a method of controlling biological fouling in water systems and process streams using hops extract, a naturally-occurring biological control agent, which is safe and environmentally compatible.
It would also be desirable to provide novel biocidal compositions containing hops extract, in combination with other biocides.
It would furthermore be desirable to provide novel biocidal compositions containing hops extract stabilized with surfactants to prevent hops extract product degradation, separation and precipitate formation prior to application. This surfactant-stabilized hops extract may contain hops extract alone or in combination with other biocides.
SUMMARY OF THE INVENTION
The present invention calls for adding hops extract to a water system or process stream to control biological fouling. Hops extract can be applied with greater safety, convenience and lower environmental impact than currently available biocides.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is directed to a composition and method of controlling biological fouling in water systems and process streams. In accordance with this invention, hops extract is added to the water system or process stream.
As used herein, “hops extract” is defined as extracts which are primarily composed of beta acids, but which may also contain alpha acids. “Beta acids” are defined as lupulone, colupulone, adlupulone, hydrogenated lupulone, hydrogenated colupulone, hydrogenated adlupulone, mixtures thereof and the salts thereof. “Alpha acids” are defined as humulone, cohumulone, adhumulone, hydrogenated humulone, hydrogenated cohumulone, hydrogenated adhumulone, and the isomerized (cis- and trans-) alpha acids, their congeners and their hydrogenated forms, mixtures thereof and the salts thereof.
The biological growth controlled by the method of the present invention may be microbiological or macrobiological in nature. As used herein, “control” is defined to include inhibition, killing and removal. Microbiological growth includes bacteria, fungi, algae and combinations thereof. Macrobiological growth includes, but is not limited to, zebra mussels, blue mussels and the Asiatic clam.
The water systems to which hops extract may be added to control biological fouling include potable waters, cooling waters; food, beverage, and industrial process waters; pulp and paper mill systems; brewery pasteurizers; sweetwater
Barnes Howard Raymond
Cooper Andrew J.
Dallmier Anthony W.
Breininger Thomas M.
Cummings Kelly L.
Davis Ruth A.
Lankford , Jr. Leon B.
Nalco Chemical Company
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