FI971902A - Method for treating milk - Google Patents

Description

Method for treating milk

The present invention relates to a method according to the preamble of claim 1 for the treatment and utilization of antibiotic-treated cow's milk.

The invention also relates to the use according to claim 8.

The most common antibiotic-treated dairy cow disease is mastitis. One treatment period lasts 3-5 days, after which the antibiotic is excreted in the milk for another 5 days. Milk from cows treated with antibiotics must not be used for human consumption. For this reason, in connection with mastitis, milk unfit for human consumption is obtained for 8-10 days. The total amount of milk produced during that period is 200-300 liters.

Antibiotic milk is a biological waste, the disposal of which causes costs and hygiene problems. Milk is commonly used as a drinking food for calves. However, this is not allowed and the use of medicinal antibiotics (such as penicillin) in animal feed is prohibited by law throughout the EU. It has been found that watering antibiotic-containing milk alters the bacterial population in the gastrointestinal tract of a calf so that antibiotic-resistant strains increase. These strains may infect other animals and also transmit resistance to human bacteria.

Methods for removing β-lactam antibiotic residues from milk are already known. Thus, the ability of the β-lactamase enzyme to degrade β-lactam antibiotic residues in e.g. milk has been known since the 1950s. This can be seen e.g. GB patent publication 905 687. However, it has generally been considered that milk containing β-lactamase residues cannot be used, for example, for human consumption. Not all β-lactamase residues in milk can be heat-inactivated, and after treatment at 100 ° C, almost 40% of the enzyme activity remains in the milk. Consumption of such dairy products may even be dangerous for individuals receiving oral penicillin therapy. A - to Thus, Korycka-Dahl et al. are of the opinion that products treated with lactamase should be labeled (Korycka-Dahl et al., Journal of Dairy Science 68 (1985) 1910-1916). The article therefore suggests the use of an immobilized enzyme.

For the reasons set out above, among others, the use of β-lactamase has not become widespread but has even been banned in many countries; Known solutions are described, for example, in U.S. Patent Nos. 4,238,521, 4,689,151 and 5,310,565.

However, the disadvantages of filtration or ion exchange methods are the complexity of the equipment and the high investment costs. Thus, so far, there has been no simple and sufficiently inexpensive way to remove an antibiotic.

The object of the present invention is to eliminate the drawbacks associated with the prior art and to provide a novel solution for the treatment and utilization of antibiotic-containing milk.

The invention is based on the idea that milk containing β-lactam antibiotics is treated with the enzyme β-lactamase to eliminate antibiotic residues, after which the milk is fed to the animals as feed or used as feed material. In connection with the invention, it has surprisingly been found that milk containing β-lactamase residues, when used in this way, is safe for animals. It has been found that β-lactamase is a protein that is not absorbed from the intestine as such, but is digested like any other dietary protein and absorbed as amino acids. Milk containing antibiotic residues can therefore be used as animal feed and the selection of resistant pathogens by antibiotic residues in animals can be prevented. Furthermore, milk containing antibiotic residues is prevented from being consumed for human consumption by possible use of milk as animal feed.

More specifically, the method according to the invention is mainly characterized by what is set forth in the characterizing part of claim 1.

The novel application according to claim 8 comprises the use of β-lactamase for the treatment of feed and feed raw materials from antibiotic-treated animals for the degradation and disposal of penicillin, ampicillin, amoxicillin or cephalosporin residues.

The invention achieves considerable advantages. Thus, the invention allows the removal of penicillin and certain other β-lactam antibiotics from milk and other feeds under barn conditions, without technical equipment. Due to mastitis, the value of medicated cow's milk as feed is FIM 200-300 per case, which amount is saved (in addition to the disposal costs) if the milk does not need to be disposed of. Milk or a similar product can be given, for example, to calves as drinking feed or it can be used as a feed material (e.g. milk powder can be made from it). The price of milk processed according to the invention is competitive with the price of other calf feeds.

The environmental risk posed by antibiotic residues can be reduced when antibiotic-containing milk is not disposed of with manure.

Consumer confidence in the purity of food and its primary production can be increased by demonstrating that antibiotic milk is properly cared for.

It should be noted that although the treatment of antibiotic-containing milk is described below, antibiotics can also be removed from other feeds derived from medicated lives by developing a dosage form of the enzyme. In this way, minced meat suitable for pets is obtained, for example, from carcasses unfit for human consumption due to antibiotic residues.

The presently developed preparation can also remove β-lactam antibiotics other than penicillin, for example ampicillin and amoxicillin. By extending the specificity of the enzyme, it is also possible to remove partially β-lactamase-resistant antibiotics, for example cephalosporins.

The invention will now be examined in more detail by means of a detailed description.

For processing, purified β-lactamase enzyme produced by the bacterial strain Bacillus cerras is added to the milk. There are no reproducible bacteria with the enzyme. The enzyme breaks down active penicillin. The duration of the treatment is about 1 min to 72 h, preferably about 10 min to 48 h, particularly preferably about 1 to 36 h, and the temperature is about 5 to 60 ° C, preferably about 10 to 40 ° C. Typically, the enzyme lactamase degrades penicillin during treatment at room temperature for about 1 day.

The amount of enzyme to be added is 0.01 to 1000, preferably about 0.1 to 100, particularly preferably about 0.5 to 50 IU / l of milk. Typically, about 2-4 IU of enzyme per liter of milk is administered. A larger amount is used to treat the milk obtained during the treatment, a smaller amount to the milk milked after the treatment.

Incubation takes place at room (barn) temperature, for about 1 day. A bucket or other container for storing feed milk can be used as the incubation vessel.

After the treatment shown, the final product contains penicillin <0.005 IU / ml, which is the limit value for milk acceptable for human consumption. The final product has an enzyme activity of <4 IU / l due to the addition of enzyme, which corresponds to <0.00015 mg / l as protein.

Preferably, a tracer, such as starch and / or colorant, is added to the finished product. If necessary, the tracer can be used to control that the treated milk is not used for human consumption.

The milk produced as a final product is completely safe for use as animal feed. The amount of active enzyme that enters the gastrointestinal tract of the animal with the treated milk is negligible and drinking the milk containing the product does not significantly increase the amount of β-lactamase in the intestine. It is digested like other feed proteins. The enzyme β-lactamase is not a foreign substance in the body. It is synthesized in large quantities by gastrointestinal bacteria if the animal is medicated or given penisil-containing milk as feed. Indeed, Gram-negative bacteria, including intestinal bacteria, have developed the ability to produce β-lactamase both by their own genes and under the control of genetic material obtained as a plasmid (Medeiros, A., β-lactamases, British Medical Bulletin 40 (1984) 18-27). Penicillin-containing milk bacteria also synthesize β-lactamase during milk storage.

The degradation products of penicillin that come into contact with the treated milk are not bactericidal, so they do not select for penicillin-resistant strains of the intestinal bacterial strain. A commercially available β-lactamase enzyme is used as the raw material for the product.

The following example illustrates the invention:

Example

Raw milk with a fat content of about 4% is milked from cows treated with penicillin G against mastitis. Milk contains β-lactam residues of about 0.5 IU / ml. The milk is incubated at room temperature with a β-lactamase enzyme produced by the Bacillus rera / .v bacterial strain in an amount of 2 IU / l. The duration of the incubation is about 24 hours. After this period, the concentration of β-lactam residues is less than 0.005 IU / ml and the β-lactamase activity is about 1.5 mIU / ml.

Processed milk is watered for calves like normal milk or drinking feed. Thus, there are no restrictions on watering due to the use of β-lactamase.

Claims (8)

A method for the treatment and utilization of antibiotic-treated cow's milk, wherein the milk is treated with β-lactamase to degrade antibiotic residues in the milk, characterized in that - the milk treated with β-lactamase is fed to the animals as feed or used as feed material. Method according to Claim 1, characterized in that the milk is administered to the calves as a drinking fodder or is used for the production of milk powder. Process according to Claim 1 or 2, characterized in that β-lactamase is used for treating about 3 to 5 IU per liter of milk obtained during antibiotic treatment and 0.5 to 3 IU per liter of milk for milk after treatment. Process according to one of Claims 1 to 3, characterized in that a tracer, such as starch, is added to the β-lactamase-treated milk to control that the treated milk is not used for human consumption. Method according to one of the preceding claims, characterized in that a purified β-lactamase enzyme produced by the bacterial strain Bacillus cereMS is used. Method according to one of the preceding claims, characterized in that the milk obtained from a cow treated with penicillin, ampicillin, amoxicillin or keylosporin is treated. Process according to one of the preceding claims, characterized in that the treated milk contains an antibiotic of <0.005 IU / ml and an enzyme activity of <: 4 IU / l. 8. Use of β-lactarnase for the treatment of feed milk from antibiotic-treated toys for the breakdown and disposal of residues of penicillin, ampicillin, amoxicillin or cephalosporins.