Chemistry: electrical and wave energy – Processes and products – Processes of treating materials by wave energy
Reexamination Certificate
2000-06-26
2002-04-23
Wong, Edna (Department: 1741)
Chemistry: electrical and wave energy
Processes and products
Processes of treating materials by wave energy
C204S158200, C205S701000, C205S742000
Reexamination Certificate
active
06375809
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of sterilizing products and a method of packaging products.
In more detail, the present invention relates to a method of sterilizing products using in combination ultraviolet rays and electrolytic water obtained from water not containing sodium chloride, and to a method of hygienically packaging products using in combination the aforesaid electrolytic water and ultraviolet rays.
In the present invention, the term “product” means food and drugs.
Also, in the present invention, “practically neutral” means having a pH close to neutral, and means in particular being in a pH range of 5.0 to 6.5.
2. Description of the Related Art
Previously, as methods of sterilizing products, various methods such as heating sterilization, chemical sterilization, or irradiation sterilization have been practiced; known methods of irradiation sterilization include irradiation with &ggr; rays, x rays, or ultraviolet rays. Also, methods using chemicals include for example methods using halogen-based sterilizing agents such as chlorine or iodine, methods using oxygen-based sterilizing agents such as hydrogen peroxide or ozone, and methods using gaseous sterilizing agents such as ethylene oxide or propylene oxide. Of these methods, hydrogen peroxide is employed in a wide range of applications on account of the vigorous oxidizing action of the oxygen which it generates (see “New Food Product Sterilization Engineering” by Isao Shibazaki, August 1983, Korin Company Limited).
As described above, in particular in the field of food products, various methods of sterilization are employed. In particular in packaging products using a packaging member, sterilization of the packaging member is performed in order to guarantee hygiene. That is, in for example retort food products, except for the case where sterilization is conducted after packaging the food product, when packaging the food product, it is important to package this in a hygienic condition by thoroughly sterilizing the packaging member.
For sterilizing a packaging member, the various sterilization methods described above may be used alone or in combination. For example, taking the case of a filling machine for filling paper containers with cream soup, the packaging member is a paper container, this paper container is sterilized by bringing it into contact with 0.1% hydrogen peroxide then irradiating it with ultraviolet rays, after which it is filled with separately sterilized cream soup, sealed and packaged (see for example WO 80/01457, Catalogue of Tetrapack Inc.).
However, in recent years, the sterilizing effect of electrolytic water obtained by electrolysis of various solutions has become known, and methods of sterilization using such electrolytic water have been established. For example, sterilization by a combination of ultraviolet rays and electrolytic acidic water, by replacing the 0.1% hydrogen peroxide referred to above by electrolyzed water, may be considered (Laid-Open Japanese Patent Publication No. 9-154924. Hereinbelow this will be referred to as the prior art).
In this prior art, “electrolytic water” is taken to mean ordinary conventional electrolytic water; such conventional ordinary electrolytic water was obtained by electrolysis of water to which sodium chloride had been added (Japanese Patent No. 2627100).
In this prior art referred to above, since electrolytic water obtained by electrolysis of water to which sodium chloride had been added was employed, there was a residual content of sodium chloride tending to cause contamination of the equipment by sodium chloride.
This therefore gave rise to the problem that crystals of sodium chloride might be deposited on the surface of the sterilized product or, if used for product packages, sodium chloride might be left behind on the packaging member affecting the taste of the packaged food product.
A further problem was that sodium chloride gave rise to various difficulties as far as the equipment was concerned, such as corrosion being caused by adhesion of sodium chloride to metal surfaces of the equipment, making this method unsuitable for use over a long period.
Furthermore, in the prior art referred to above, the electrolytic water was usually used in a strongly acidic condition. However, the dissolved condition of chlorine in strongly acidic electrolytic water is unstable so the dissolved chlorine is volatilized in a short time as chlorine gas, giving rise to the problem of instability of the sterilization effect. In order to ensure a satisfactory sterilization effect, it was therefore necessary to set the chlorine concentration of the electrolytic water beforehand at a high level. This was therefore undesirable in view of the problem of corrosion of metallic surfaces by the chlorine or in regard to safety of the working personnel etc.
Furthermore, in the prior art referred to above, when ultraviolet irradiation was performed, it was necessary to perform irradiation with ultraviolet rays for a long time of 10 seconds or more, preferably more than 30 seconds. This led to the problem, in for example, a machine for packing cream soup, that the treatment time when performing sterilization of the paper container was long, lowering the overall productive capacity. That is, this prior art was unsuited to mass production and its industrial utilization as a method for packaging products was attended by many difficulties.
Specifically, the prior art referred to the above using conventional electrolytic water suffered from the problems of being unsatisfactory in regard to product quality, equipment life, maintenance and management, ensuring the safety of working personnel, and of being unsuited to mass production.
SUMMARY OF THE INVENTION
The present invention provides a method of sterilizing products and a method of packaging products, that little denature the products, little concern with rust or corrosion and the like of the equipment, that affords a safe working environment, and can shorten the treatment time.
The present invention relates to a method of sterilizing products, which comprises adding hydrochloric acid to water not containing sodium chloride, passing the resulting fluid through a diaphragm-less electrolytic bath, subjecting the resulting fluid to electrolysis, collecting the electrolytic water, diluting the electrolytic water with water, and then sterilizing the products with both the diluted electrolytic water and ultraviolet rays, and to a method of packaging products with packaging members sterilized by the above process.
With the method of sterilizing products according to the present invention, outstanding benefits are obtained such as that 1) since no residue of sodium chloride is left after sterilization, there is no concern regarding rusting of metallic surfaces of the equipment due to sodium chloride, 2) since the electrolytic water is practically neutral and of low chlorine concentration, there is little corrosion of metallic surfaces due to oxygen and chlorine and the safety of the working environment is high, and 3) there is little risk of denaturing the products, and the treatment time is short.
Also, the method of packaging products according to the present invention has outstanding benefits such as that 1) since there is no residue of sodium chloride after packaging, there is no denaturing of products due to sodium chloride, and, in addition, there is no concern regarding rusting due to sodium chloride of the metallic surfaces of the packaging equipment, 2) since the electrolytic water that is used is practically neutral and of low chlorine concentration, there is little likelihood of corrosion due to oxygen and chlorine of metallic surfaces of the packaging equipment, and safety of the working environment is high, and also 3) it is suited to mass treatment.
An object of the present invention is to provide a method of sterilizing products using in combination electrolytic water and ultraviolet rays, which little denatures the products, little concerns with rust and corrosi
Doi Toyohiko
Kato Ryo
Suzuki Kiyoshi
Morinaga Milk Industry Co. Ltd.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Wong Edna
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