IL123089A - Method for sanitizing udders and milking units - Google Patents

Abstract

A method for the prevention of mastitis and/or other diseases of the mammary glands of milk-producing mammals, which comprises sanitizing teats and udders of such mammals, and/or the components of a machine for milking such mammals, by applying to the teats and udders, and/or said components, ozonated water having an ozone content which lies within the range between 0.01 mg and 5 mg ozone per liter of water.

Description

METHOD FOR SANITIZING UDDERS AND MILKING UNITS Applicant: Ozomilk Ltd.

OZO 345/1.1 METHOD FOR SANITIZING UDDERS AND MILKING UNITS Field of the Invention The present invention relates generally to the dairy industry and in particular to a novel method for sanitizing the udders and teats of cows and other mammals which provide milk for human consumption. The novel method may also be used for sanitizing various components of the milking units, such as the claws and the liners of the teat cups.

Background of the Invention One of the most significant problems faced by the dairy industry is the cleaning and sanitizing of the equipment involved in the process of milking. The sanitizing is necessary to ensure not only the health of the consumers who drink the milk but also the health of the cows and other mammals who provide the milk. The physical environment of cows and other milk-producing mammals is far from being clean; they are often covered with mud, insects, agricultural debris and the like, and are constantly exposed to a wide variety of bacteria and other pathogens. As a consequence, the mammals themselves, in particular the udders and the teats, must be cleansed and sanitized prior to milking, to minimize the contamination of the milk drawn from them and to prevent infection of the mammary gland (mastitis) by bacterial contamination. In addition, the equipment used in the milking process, in particular the "teat cups" that are attached to the teats and which are part of standard pneumatic/mechanical automatic milking apparatus must also be properly cleaned and sanitized, so as to prevent the transfer of bacteria and other pathogens from one animal to the next and to prevent contamination of the milk as it is being conveyed to storage tanks.

Various methods are known and used in the dairy industry in connection with the cleansing and sanitizing of the equipment involved in the milking process. These include the washing of the udders utilizing streams of water under pressure, dipping or spraying the udders and teats with one or more bactericides, and the flushing and "back- washing" of the milking apparatus with water, detergents and the like.

However, at least two serious drawbacks have been encountered in the dairy industry when utilizing the known methods for sanitizing udders and associated milking equipment. The first drawback stems from the fact that the various bactericides that have been certified for use by health authorities have a long "contact time", i.e. they must remain on the udders and other surfaces to which they are applied for a minimum of 25 seconds if they are to be effective. The second drawback stems from the fact that the bactericides and any other substance applied to the udders must be completely washed off prior to the milking, so as to prevent any residues from entering the milk itself. Both the long contact time of the certified bactericides and the need to wash off the bactericides from the udders and the associated milking equipment before each cow is attached to the milking machine result in a significant lengthening of the actual milking time of an average herd of cows (which may well number in the hundreds). For many dairy farmers, whose margin of profit is very small, this lengthening of the milking process is economically unacceptable. As a consequence, many dairy farmers do not sanitize their cows prior to milking, and merely rinse the udders with water. For the same reason, many dairy farmers do not sanitize the claws, teat cups and teat cup liners which come into contact with the cows, between the milking of one cow and another, and do so only after the whole herd has been milked. This practise significantly increases the probabilities that mastitis (infection of the mammary glands) or other diseases may be spread from one animal to another.

US Patent 5,211,961 describes a gel composition for cleaning and sanitizing the teats and udder of an agricultural animal for machine milking. In accordance with this patent, residual surface water, which is a source of milk contamination and mastitis, is eliminated from the teats and udder by use of the gel composition. The gel composition comprises water, a germicide added to the water in concentration sufficient to kill environmental bacteria which cause mastitis, an aqueous gelling agent, a soap or a detergent, and a skin softener. The composition is applied to the teats and acts as a cleansing and sanitizing agent; however, prior to milking, the gel must be wiped from the teats and the teats thoroughly cleaned prior to attachment to the milking machine.

US Patent 5,567,444 (to Ecolab) describes a method for cleaning and sanitizing soiled solid surfaces, especially in-place process facilities. The method involves contacting the soiled surfaces with an aqueous ozone cleaning composition having a pH of at least 8 and comprising an effective ozone composition sufficient to produce an oxidation-reduction potential of at least +550 mV with respect to an Ag/AgCl reference electrode, and then circulating an aqueous sanitizing composition containing hydrogen peroxide, a Cr C10 peroxyaliphatic carboxylic acid or a mixture thereof sufficient to reduce the oxidation-reduction potential below about +400 mV. One of the process facilities stated to be suitable for the use of such a method is a milk-line dairy.

ACKNOWLEDGMENT OF CITED PRIOR ART US Patent No. 5.332,51 1 relates to a process for sanitizing water in, e.g., swimming pools, by using a combination of specified bactericidal chemicals, optionally using chlorine or ozone intermittently. US Patent No. 5.227, 184 relates to a method for sanitizing food while immersed in a liquid bath, by-streaming ozone containing bubbles therethrough.

US Patent No. 4.849,237 relates to a method for sanitizing poultry carcasses using ozonated water at sl ightly above freezing temperatures such as 33°F.

Summary of the Invention The present invention provides a novel method for the prevention of mastitis and/or other diseases of the mammary glands of milk-producing mammals, which comprises sanitizing the teats and udders of such mammals, and/or the components of a machine for milking such mammals, which overcomes the drawbacks inherent in the methods utilized today in the dairy industry. The method consists of applying to the teats and udders, and/or to said components, ozonated water having an ozone content which lies within the range between 0.01 mg and 5 mg ozone per liter of water. In particular, the present invention enables the sanitizing of the teats and udders, as well as the sanitizing of the milking equipment which comes into contact with the bodies of the mammals being milked, w ithout the need to substantial ly interrupt the milking process so as to carry out the sanitizing process. The "contact time" is very brief and there are no traces or residues of potentially harmful bactericides. The method is particularly beneficial in enabling the sanitizing process to be carried out between the attachment of each cow to the milking machine, thereby assisting a much greater level of sanitizing than is obtained using conventional techniques. In addition, when using the present invention, it is possible to cut back significantly on the amount of water and detergents that need to be used in the cleansing and back-flushing of the milk line, such that the present invention is also economically advantageous for dairy farmers.

In accordance with a preferred embodiment of the present invention, the method comprises the steps of (a) rinsing the teats and udders with water; and (b) applying a solution of ozonated water to the teats and udders. Also in accordance with a preferred embodiment of the invention, the ozonated water is applied by dipping the teats and udders in a solution of ozonated water or by the spraying of the teats and udders with a solution of ozonated water. Further in accordance with a preferred embodiment of the " invention, the effective concentration of ozone in the ozonated water is between the range of 0.05 mg and 1 mg ozone per liter of water. In accordance with a preferred embodiment of the invention, the teats and udders of each mammal in the herd of mammals being milked is sanitized with the ozonated water immediately prior to the attachment of the mammal to the milking machine and optionally also immediately after detachment from the milking machine.

As more fully described herein, the present invention also encompasses the use of ozonated water for the sanitizing of teats and udders of milk-producing mammals. In accordance with a preferred embodiment of the invention, the ozonated water is applied by dipping the teals and udders in a solution of ozonated water or by the spraying of the teats and udders with a solution of ozonated water. Further in accordance with a preferred embodiment of the invention, the effective concentration of ozone in the ozonated water is between the range of 0.05 mg and 1 mg ozone per liter of water. In accordance with a preferred embodiment of the invention, the teats and udders of each mammal in the herd of mammals being milked is sanitized with the ozonated water immediately prior to the attachment of the mammal to the milking machine, and optionally also immediately after detachment from the milking machine.

The present invention also provides a simple, effective method for preventing mastitis and other diseases of the mammary glands of milk-producing mammals, the method comprising the steps of (a) rinsing the mammary glands with water; and (b) applying a solution of ozonated water to the mammary glands. In accordance with a preferred embodiment of the invention, the ozonated water is applied by dipping the teats and udders in a solution of ozonated water or by the spraying of the teats and udders with a solution of ozonated water. Further in accordance with a preferred embodiment of the invention, the effective concentration of ozone in the ozonated water is between the range of 0.05 mg and 1 mg ozone per liter of water. In accordance with a preferred embodiment of the invention, the teats and udders of each mammal in the herd of mammals being milked are rinsed with the ozonated water immediately prior to the attachment of the mammal to the milking machine, and optionally also immediately after detachment from the milking machine.

The present invention also provides an effic ient method for sanitizing the components of a milking machine, which comprises flushing the components with ozonated water having an ozone content which lies within the range between 0.01 mg and 5 mg ozone per liter of water. This method may be applied to e.g. sanitizing 123089/2 the teat cups and/or other components of a milking machine, by an embodiment comprising flushing the teat cups and/or other components with ozonated water In accordance with a preferred embodiment of the invention the concentration of ozone in the water is between the range of 0.05 mg and 1 mg ozone per liter of water.

Detailed Description of the Invention The present invention utilizes the knowledge that has been developed concerning the powerful effect of ozone as an oxidizer and disinfectant, and applies this knowledge to the dairy industry. Ozone (CAS No. 10028-15-6) is a naturally occurring triatomic form of oxygen. It is a gas at both ambient and refrigerated temperatures. Ozone is produced naturally by the effect of solar ultraviolet radiation on atmospheric oxygen. The stable bonds of an oxygen molecule are cleaved into two short-lived oxygen atoms which react almost immediately with another oxygen molecule to form ozone. At ground level, ozone is produced when lightening is discharged through the atmosphere, and this is the cause of the familiar, fresh, clean smell of air following a thunderstorm.

Commercially, ozone has been in use for well over a hundred years in connection with the treatment of drinking water. As of 1993, there were more than 2,500 large scale water-treatment installations which utilized ozone as a means for purifying and treating water. Ozone is also used in the treatment of swimming-pool water and in the treatment of odors from industrial processes and municipal secondary effluents. Industrial high quality water supplies also are often treated with ozone, for example in breweries and in the production of soft-drinks.

Ozone is a powerful oxidant and as such is very useful as a disinfectant. It is considered to be the most efficient disinfecting agent for water, being more efficient than substances such as chlorine dioxide, hypochlorous acid, hypochlorite ion, dichloramine, and rnonochloramine.

Ozone is also a powerful bactericide. It attacks the bacterial membrane at the glycoproteins and glycolipids, or at certain amino acids such as tryptophan. It also acts on the sulfhydryl groups of certain enzymes, resulting in the disruption of normal cellular enzymatic activity. Bacterial death is rapid and has been attributed to changes in cellular permeability in consequence of the high oxidant concentration.

Ozone further acts on the nuclear material of the bacterial cell by modifying the purine and the pyrimidine bases of nucleic acids. Ozone is effective against Gram-positive (including spore-formers) and Gram-negative bacteria, viruses, and protozoa.

Ozone has many applications in the food industry. It is used to increase the yield of certain crops, to protect raw agricultural commodities during storage and transit, and to sanitize water used for washing food equipment, foods, and packaging materials.

Ozonation is classified by the United States Food and Drug Administration (FDA) as Generally Recognized As Safe (GRAS) for the treatment of bottled drinking water, when used in accordance with good manufacturing practices. The approved maximum residual level at the time of bottling is 0.4 mg of ozone per liter of bottled water. The use of gaseous ozone up to 0.1 ppm in meat-aging coolers has also been accepted by FDA. In 1997, an Expert Panel Report provided an unequivocal declaration of GRAS status for ozone for use in food processing.

One of the most important characteristics of ozone that make it attractive for use as a sanitizer in the food industry and elsewhere is that it does not leave any residues, since it does not remain in water for a very long period of time. As a consequence, ozonation may be considered to be a process rather than a food additive, with no safety concerns about possible consumption of residual ozone in food products. Any by-products that ozone may produce in the treatment of foodstuffs are similar to normal oxidation products, and thus are not likely to have deleterious health effects.

The inventors have discovered that ozonated water can also be used both efficiently and effectively as a sanitizer for the dairy industry, in particular in the sanitizing of the teats and udders of cows and other milk-producing mammals, and the sanitizing of the milking apparatus itself. Ozonated water, at a concentration of up to 5 mg/liter, is very effective in destroying the bacteria and other pathogens that are found on the udders of milk-producing mammals, and therefore is a highly effective sanitizer. The bactericide effect of ozonated water is almost immediate, such that it may be applied to the udders and teats immediately prior to the milking, thereby assuring a very high level of sanitizing, without any concomitant lengthening of the milking process. In addition, as a consequence of the fact that ozonated water does not leave any undesirable residues, there is no basis for concern lest any artifact or 123089/2 other by-product of the sanitizing by ozonated water will contaminate the milk. In principle, there is no need to remove the ozonated water after it has been applied to the teats and udders; however, a simple rinsing with plain water may be done, if this is found to be desirable. Furthermore, because it is possible to apply the ozonated water to the udders with relative ease and speed, it is possible to do the sanitizing before each and every cow is attached to the milking machine, thereby achieving a degree of sanitizing that is not obtainable currently by conventional methods.

Optionally, so as to provide an additional degree of sanitizing, the udders and teats of each mammal may be rinsed again with ozonated water, after the conclusion of the milking and the separation from the teat cups.

The present invention is particularly advantageous in that it does not necessitate any substantive alteration of the milking process or of the milking machines currently in use. There are many commercially available ozone generators, such as Azcozon VMUS-4, manufactured by Azco Industries Limited (Surrey, British Columbia, Canada), and these may readily be adapted for use in the implementation of the present invention. The ozone generator may simply be attached by an injector in a conventional manner to the source of water that is used both for the cleansing of the mammals and the cleansing of the milking apparatus, provided of course that the ozone is in contact with water for a time sufficient for the production of ozonated water. Prior to the attachment of each mammal to the teat cups, the udders and teats of the mammal are thoroughly washed, first with plain water, and then with ozonated water, the latter having a concentration of ozone sufficient to be an effective bactericide. A minimum concentration of 0.01 mg ozone per liter of water has been found to be necessary, and a concentration of up to 5 mg/liter Is more than sufficient; preferably, the concentration is between 0.05 mg and 1 mg ozone per liter of water. The pre-milking washing and sanitizing may be done in any conventional manner, in the holding area, the sprinkler pen of the milking parlor or in the milking parlor itself, either by dipping the udder and teats in the ozonated water or by spraying the ozonated water on the teats and udders. In parallel, the teat cups themselves, including the liners, pipes and other hardware associated with them are also thoroughly flushed with the ozonated water, thereby assuring that the equipment which comes into immediate contact with the mammals is thoroughly sanitized.

Ozonated water, in accordance with the invention, as described above, may be used effectively either in addition to or in place of other means of sanitizing currently used in the dairy industry. Because ozonated water is such an efficient bactericide, the use of ozonated water in accordance with the invention is also beneficial in the prevention of mastitis, and in preventing the spread of disease from one animal to the other, which often occurs today due to the fact that the teat cups are not sanitized after being used by each animal.

Ozonated water, in accordance with the invention, may also be used most effectively in sanitizing other component parts of the milking apparatus. Thus, after the whole herd has been milked and the collected milk has been emptied from the collection tank, ozonated water can be used to flush the whole system (including the bulk tank), preferably after a prior cleaning of the system with a detergent, as is conventionally done. Because ozonated water is such an efficient bactericide, when using ozonated water in accordance with the invention, significantly less water and detergents are needed for the proper cleansing and back-flushing of the milk line. Thus, the present invention not only provides a simple and efficient method of sanitizing, but it also provides significant economic benefits for the daily industry.

Ozone is dissolved in water with difficulty, so that merely dispersing in water, bubbles of air containing ozone, and then immediately feeding the obtained dispersion to a site of application (see, e.g. EP 0819388) would not be regarded as a use of ozonated water in the sense of a solution of ozone in water. Thus, for the avoidance of doubt, it may be noted that such terms as "ozonated water", "solution of ozonated water" and similar expressions in the present specification and claims, means water containing dissolved ozone. Similarly, any reference to ozonated water which contains a stated amount of ozone is intended to convey that the stated amount of ozone is dissolved in water.

The present invention utilizes water containing dissolved ozone ("ozonated water") within prescribed limits of concentration, under ordinary working conditions, thus enabling better control from the standpoints of human and animal health, and ecology.

For the sake of clarity, it is to be understood that the present invention is applicable to automated milking procedures and equipment, including robotic milking procedures and equipment. 123089/2 The invention will be illustrated by the following Example.

Example: The effect of ozonated water on infection in a milking unit Each cup of an experimental milking unit was assembled with a stainless steel tap on the short milk tube. Two teat cups were designated and marked as control teat cups (plain, tap water flushing) and the other pair was designated and marked as the experimental teat cup for ozonated water flushing. The long milk tube was connected to a two-way tap which was connected to an ozonated water source or plain tap water source. Teat cup liners were backfiushed with plain water or ozonated water by setting up the short milk tube taps as required. In order to prevent contamination of plain water with ozonated water, the control teat cups were always flushed with plain water before the ozonated water flushing of the experimental teat cups. All liners were made of rubber and their age was over 1,000 milkings.

The bacterial strains used in this study were Escherichia coli and Stahylococcus aureus originally cultured from milk samples obtained from field cases of mastitis. Using standard methods, a suspension of approximately 109 colony forming units (CFU) per ml of each organism was prepared in nutrient broth, pH 7.2. 40 ml of the bacterial suspension were thoroughly mixed with 460 ml of 3% fat, UHT milk in room temperature. The four teat cups were turned upward, the taps on the short milk tube were turned off, 130 ml of the bacterial milk suspension was poured into each liner, and sterile stoppers were inserted into the mouthpieces. Teat cups were repeatedly inverted and manually shacked. The contamination level of the liners differed between experiments and was also dependent on contact time, 1 minute in experiments 1 and 2, 30 minutes in experiment 3 and 2 hours in experiment 4.

Samples of 20 μΐ of the original bacterial milk suspension and teat cup milk were streaked onto sheep-blood agar plates with esculin. All contaminated milk was poured out of the liners and teat cups were thoroughly shaken. In experiments 1 and 2, two control teat cups were not flushed and the other pair was flushed with 4 liters of ozonated water. In experiments 3 and 4 two teat cups were flushed with 4 liters of plain tap water and thereafter the other pair was flushed with 4 liters of ozonated water. Just prior to flushing, the concentration of ozone in the ozonated water was tested using the DPD photometric method. Sterile normal saline and swabs were used to recover bacteria from the inner surface of liners. The four teat cups were turned upward, the taps on the short milk tube were turned off, 25 ml of sterile normal saline was poured into each liner, and sterile stoppers were inserted into the mouthpieces. Each teat cup was inverted and shacked for 4 minutes. Samples of 30 μΐ saline were aspirated from each liner and streaked onto sheep-blood agar plate with esculin. Sterile cotton swabs were moistened in sterile normal saline and rolled onto the inner wall of each liner using repeatedly the same technique. The swabs were streaked onto sheep-blood agar plated with esculin. All plates were incubated at 37°C and growth was observed and recorded at 48 hours.

Results: Cultures of the original bacterial milk suspension and teat cup milk yielded confluent, carpet growth on the plates in all the experiments.

Experiment 1 : Liners contaminated with Staphylococcus aureus and 2 teat cups were flushed with 4 liters of 0.87 mg/L ozonated water. Culture of the teat cup saline rinsing solution yielded 210 and 140 colonies of Staphylococcus aureus for the two control, unflushed cups. No bacteria were cultured from the rinsing solution of the two ozonated water flushed cups.

Experiment 2: Liners contaminated with Escherichia coli and 2 teat cups were flushed with 4 liters of 0.89 mg/L ozonated water. Culture of the teat cup saline rinsing solution yielded 250 and 93 colonies of Escherichia coli for the two control, unflushed cups. No bacteria were cultured from the rinsing solutiori of the two ozonated water flushed cups.

Experiment 3 ; Liners contaminated with Staphylococcus aureus and 2 teat cups were flushed with 4 liters of 1.23 mg/L ozonated water. Culture of the teat cup saline rinsing solution yielded 60 and 50 colonies of Staphylococcus aureus for the two control, water flushed cups. No bacteria were cultured from the rinsing solution of the two ozonated water flushed cups.

Culture of swabs taken from water flushed teat cups yielded 88 and 100 colonies of Staphylococcus aureus. Cultures of swabs taken from ozonated water flushed teat cups yielded no growth. 8 1 Experiment 4: Liners contaminated with Staphylococcus aureus and 2 teat cups were flushed with 4 liters of 1.03 mg L ozonated water. Culture of swabs taken from water flushed teat cups yielded approximately 106 colonies of Staphylococcus aureus. Cultures of swabs taken from ozonated water flushed teat cups yielded 15 and 120 colonies of Staphylococcus aureus. This is a 4 Log or 99.99% reduction of bacterial counts.

Repeated flushing of the milking unit and teat cup liners with ozonated water did not produce any observable ill effects on rubber or plastic parts.

Conclusions Flushing of teat cup liners contaminated by either Staphylococcus aureus or Escherichia coli with ozonated water solution effectively disinfected the liners and was considerably more effective than plain water flushing.

No ill effect of the ozonated water solution on the milking units was observed.

While particular embodiments of the invention have been particularly described hereinabove, it will be appreciated that the present invention is not limited thereto, since as will be readily apparent to skilled persons, many modifications or variations can be made. Such modifications or variations which have not been detailed herein are deemed to be obvious equivalents of the present invention.

Claims (8)

1. A method for the prevention of mastitis and/or other diseases of the mammary glands of milk-producing mammals, which comprises sanitizing teats and udders of such mammals, and/or the components of a machine for milking such mammals, by applying to the teats and udders, and/or to said components, ozonated water having an ozone content which lies within the range between 0.01 mg and 5 mg ozone per liter of water.

2. A method according to claim 1, wherein sanitizing said teats and udders is further characterized by at least one of the following features: (a) said ozonated water is applied by dipping the teats and udders therein; (b) said ozonated water is applied by spraying therewith the teats and udders; (c) said ozone content which lies within the range between 0.05 mg and 1 mg ozone per liter of water; (d) said method is applied to each mammal in a herd of mammals being milked, immediately prior to the attachment of the mammal to the milking machine; (e) the teats and udders are rinsed with water, prior to the application of said ozonated water to the teats and udders.

3. A method according to claim 1, wherein the teats and udders are rinsed with water both before and after applying ozonated water thereto.

4. A method according to claim 3, which is further characterized by at least one of the following features: (a) said ozonated water is applied by dipping the teats and udders therein; (b) said ozonated water is applied by spraying therewith the teats and udders; (c) said ozone content which lies within the range between 0.05 mg and 1 mg ozone per liter of water; (d) said method is applied to each mammal in a herd of mammals being milked, immediately prior to the attachment of the mammal to the milking machine. 123089/2

5. A method according to claim 1, wherein sanitizing of said components comprises flushing them with said ozonated water.

6. The method according to claim 5 wherein said ozone content lies within the range between 0.05 mg and 1 mg ozone per liter of water.

7. The method according to claim 5 wherein said components comprise any of the following: the claws, the teat cups, the teat cup liners, associated piping and the bulk collection tank.

8. The method according to claim 6 wherein said components comprise any of the following: the claws, the teat cups, the teat cup liners, associated piping and the bulk collection tank. Jeremy M. Ben-David & Co. Ltd.