GB2271848A

GB2271848A - Method of marking an animal or plant.

Info

Publication number: GB2271848A
Application number: GB9222363A
Authority: GB
Inventors: Richard James Guy
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-10-23
Filing date: 1992-10-23
Publication date: 1994-04-27
Also published as: GB9222363D0; WO1994009618A1

Abstract

In a method of marking an animal or plant, at least one stable isotope of an element, which element is naturally present in the said animal or plant, is administered to the animal or plant. The amount of the isotope or the relative amounts of the isotopes administered are so selected that the ratio of two or more isotopes of the said element to one another in the animal or plant differs from the ratio usually found in such animals or plants. A product derived from the animal or plant to which the isotope or isotopes have been administered may subsequently be identified by virtue of the deviation of the ratio from that usually found.

Description

Method of marking an animal or plant and products derived therefrom The present invention relates to a method of marking an animal or plant, involving the use of isotopes, and to a method of obtaining marked products of such animals or plants, as well as to the products so obtained.

The terms "to mark", "marking" and "marked" are used herein to refer to modification of the animal or plant by means of administering isotopes, such that, for example, the modified animal may be distinguished from an unmodified animal by any suitable method, and especially by a spectroscopic method. The term "animal", as used herein, is not intended to include humans.

In recent years, there have been growing incidences of substitution of animal and plant products of a particular origin or quality, and especially those that are more expensive, by counterfeit products, that is products that are of a different origin or of inferior quality. For example, the public has become aware, both for reasons of health and of conscience, of the desirability of eating food products produced from "free-range" animals and/or animals which have not been treated with growth-enhancing substances. Where freerange animals are raised for meat production, production of meat is more time-consuming and, in view of the larger amounts of land required, more expensive than the production of meat by production methods in which animals are confined in buildings and may be administered growthenhancing substances.As a result, meat from free-range animals is generally more expensive than meat produced in such mass production methods. Since an animal carcass may be sold before it has been divided up, and meat may be subsequently processed into a variety of different forms, the original producer cannot always use packaging to distinguish his products; it is often, therefore, difficult to differentiate meat that has been produced from free-range animals from meat that has been produced from other animals, and it seems that meat produced by the conventional mass production methods is increasingly being passed off as meat from free-range animals.

There is therefore a need for a means of marking animal or food products, for example meat, in such a way that the producer can monitor samples taken after the products have passed through the hands of others, in order to satisfy himself that all the products being described as those of the producer are in fact his.

The majority of elements exist in more than one atomic form, that is, as more than one isotopeiof the element. For any given element, the relative amounts of the isotopes occurring naturally is in most cases fixed.

For example, boron exists in two stable isotopic forms, B10 and Bllt the ratio B10 : B11 being 19.6% : 80.4% in nature. Boron is present as an essential trace element in plants and is found in trace amounts in the tissues of animals, where it is also believed to perform a specific role.

In accordance with the present invention it is proposed that, by altering the ratios of the stable isotopes of one or more elements that are naturally present in an animal or plant, it will be made possible to differentiate a product obtained from an animal or plant in which the ratio has, or the ratios have, been altered, thus enabling a producer who has altered the said ratio or ratios to ensure that all the products being sold as his products are genuine. The alteration of the isotopic balance in this way need not affect the animal's health (either adversely or advantageously) or the purity of a subsequent animal or plant product, since no foreign entity is introduced, so that a marked product would still be suitable for human consumption. The animal's metabolism will ensure that the isotope is effectively absorbed and distributed, exchanging with the isotopes already present.Furthermore, once an animal or plant has been slaughtered or harvested, the isotopic trace will be indelible as far as chemical and nonnuclear physical processes are concerned; since the ratios may be altered in an infinite variety of ways, the trace may also be quite sophisticated.

The invention provides a method of so marking an animal or plant that a product derived therefrom may be subsequently identified, comprising administering to a living animal or plant at least one stable isotope of an element, which element is naturally present in the said animal or plant (in a plurality of stable isotopic forms), the amount of the isotope or the relative amounts of the isotopes administered being so selected that the ratio of two isotopes of the said element to one another in the animal or plant differs from the ratio usually found in such animals or plants. (The isotopes should normally be present in the natural background ratio (as documented in general texts), although small variations may occur between animals or plants from different backgrounds; animals or plants grown in the same environment or of the same background should have identical isotopic ratios.) The invention further provides a method of obtaining a marked animal or plant product, comprising administering to a living animal or plant at least one stable isotope of an element, which element is naturally present in the said animal or plant (in a plurality of stable isotopic forms), and recovering the animal product or plant product from the animal or plant, respectively, the amount of the isotope or the relative amounts of the isotopes administered being so selected that the ratio of two isotopes of the said element to one another in the animal or plant product so obtained differs from the ratio usually found in such animal products or plant products.

If it is desired to give the product a specific label, the amount of the isotope or the relative amounts of the isotopes administered to the animal or plant may be so selected that the animal or plant product will contain a desired isotopic ratio or a ratio within a desired range.

It will be appreciated that it will be necessary to allow sufficient time between administration of the isotope and recovery of the product for the isotope to be assimilated by the animal or plant, and the time required may vary for different isotopes. In the case of poultry meat, it has been found that if boron is used as the isotope, it should generally be administered to the poultry at least 10 hours before slaughter. Less readily absorbed isotopes (e.g., those of iron) may, however, need to be administered earlier, for example, at least 3 or 4 days before slaughter.

Further, over a period of time the isotopic ratio will fall back towards the naturally occurring ratio once administration ceases. It is therefore preferable for the isotope(s) to be administered to the animal or plant within a short period before either the animal or the plant is slaughtered or harvested, respectively, or the product is recovered from the living animal or plant, which period is sufficient for the isotope to be absorbed and the isotopic ratio altered. In the case of boron, if a product is to be recovered after slaughtering an animal, it is desirable for administration to take place not more than 24 hours before slaughter. Other isotopes (such as iron) are retained for longer and thus may be administered up to 2 or 3 days before slaughter.It is believed that, shortly after slaughter, no significant change in the ratio will occur in meat because the metabolic processes of the animal will cease to function.

Thus, it will be appreciated that it would be difficult or impossible to reproduce a given altered isotopic ratio in animal products produced after slaughter, where the animals did not, at the time of slaughter, have the altered ratio; moreover, the present invention enables the isotope to be absorbed and distributed throughout an animal or plant body far more efficiently than could be achieved by any isotopic labelling treatments carried out after slaughter.

If it is desired to mark the product with a specific trace, the time or intervals, at which the isotope(s) is administered may be so selected that the animal or plant product will contain a desired isotopic ratio or a ratio within a desired range.

The method is of especial application where the animal or plant has been reared or cultivated substantially or totally without the use of artificial treatments to prevent disease or promote growth; that is to say, the animal or plant has not been treated with manufactured drugs or with commercially available chemical plant treatments, respectively, which drugs or chemicals would not normally be found in untreated natural living tissue. For humane reasons, the isotope or isotopes are preferably administered to an animal orally, for example, in admixture with food or in solution in water.

The product may be an animal product that can be recovered from the animal without slaughtering the animal. For example, the product may be milk or milk products, eggs or egg products, wool or silk. More commonly, the product will be an animal product that is recovered from an animal carcass after the animal has been slaughtered. The product may be meat, for example, poultry meat. The product may also be, for example, leather or fur.

The product may instead be a plant product, for example, a fruit or vegetable or a grain crop, cotton, linen, oils, essences, etc., or products derived therefrom.

The element of which the isotopic ratio is to be adjusted will preferably be an element that is present in the animal or plant in relatively small quantities (i.e., an essential or non-essential trace element), as the amounts of the administered isotope that need to be taken up to produce a measurable change in the ratio will then be smaller than in the case of elements which are relatively abundant in the animal or plant tissue. If the element selected has an essential metabolic role (e.g., as in the case of iron), it is likely to be more successively absorbed. The amount of element administered should not be so high as to harm the animal or plant or to harm subsequent consumers. Preferably, the amount of element administered is so selected that the total amount of the element in the recovered animal or plant product is not increased by more than 2 or 3 times its original content.

As mentioned above, the element may be boron. For example there may be administered to the animal or plant boron10 or boron11, or a mixture of boron10 and boron11 in relative amounts such that the ratio of B10 to B11 is greater or smaller than that occurring naturally in the animal or plant.

If desired, for increased specificity, isotopes of two elements that are naturally present in the plant or animal may be administered. For example, there may be administered a boron isotope or a boron isotope mixture in which the relative amounts of one of the boron isotopes differ from those occurring naturally, and an iron isotope or an iron isotope mixture in which the relative amounts of the iron isotopes differ from those occurring naturally. There are four iron isotopes, Fe54, Fe56, Fe57 and Fe58, which occur in nature in the following respective percentages: 5.8%, 91.7%, 2.2% and 0.3%. It will be appreciated that the adjustment of isotopic ratios of two elements increases the number of permutations possible as compared with the case where only one element is used.Similarly, where a single element exists in three or more isotopic forms, as in the case of iron, the isotopic ratios may be adjusted in a variety of ways by adding selected amounts of two or more of the isotopes of that element. Thus the marking code chosen may, if desired, be changed frequently, further discouraging the copying of the marking. The isotopic ratios of three or more elements may also be altered.

The extent to which the isotopic ratio is to be altered should be sufficient to enable the alteration to be detected by the chosen measuring method, for example, mass spectroscopy. For example, it is believed that, in the case of boron, a change from the natural B10 : B11 ratio of 19.6 : 80.4% to an altered ratio of 18 : 82% or 22 : 78% will be detectable by mass spectroscopy.

It is also possible to differentiate between two products in each of which one of the isotopes has been enriched by a different amount. For example, it is believed that it would be possible to differentiate between two products having reduced B10 : B11 ratios of 18 : 82% and 16 : 84%, to an animal respectively.

In a preferred method according to the invention, the animal product is meat, the element is boron, and the ratio of B10 : B11 is measured by mass spectroscopy.

The following Example illustrates the invention.

Example Chickens in a chicken house containing approximately 500 broiler (table) chickens, each weighing approximately 2.5kg, were selected. The chickens take drinking water from drinkers filled from a header tank containing approximately 100 dm3 of water which, in normal use, is topped up automatically from a mains supply using a conventional ball-cock.

Enriched boric acid in pure form containing no less than 90%, based on boron content, of boron10 was used.

A solution was prepared by dissolving 10g of the enriched boric acid in one dm3 water. Preliminary calculations had indicated that the minimum required exposure for livestock is roughly 0.5mg of the enriched boric acid per kg of chicken. This indicates that the birds, which weighed approximately 2.5kg each, would each need at least 1.25mg of the enriched boric acid.

At 20 hours before slaughter, the mains water supply to the header tank was cut off thus isolating the supply header tank so that the entire contents of the tank would be consumed by the 500 chickens present. 500cm3 (i.e.

0.5dm3) of the 10g/dm3 enriched boric acid solution was added to the 100dm3 of water in the header tank. The contents were stirred to ensure mixing. The tank was monitored carefully and the mains supply restored as soon as the tank had emptied.

In a separate test, involving just two 2.5kg chickens, the chickens were isolated and 10cm3 of the 10g/dm3 enriched boric acid solution was administered to the two birds 20 hours before slaughter, divided roughly equally between their sole water supply and a cereal mix, both of which were then fully consumed.

Two birds from the chicken house which received the enriched boron were slaughtered and a leg taken from each. At the same time, the two isolated birds were also slaughtered and a leg taken from each. As a control a leg was also taken from a supermarket chicken of unknown origin.

Muscle was separated from the skin, fat and bone of all the samples and the B10:B11 ratio was then measured using an Inductively Coupled Plasma Mass Spectrograph, having a resolution of about 1 part/billion (i.e., 1000 million).

The results of the tests are as set out in the table below: Total Boron ORIGIN % of Boron10 Content Supermarket chicken 20% 0.lmg/g (CONTROL) Two birds from entire 63% 0.2mg/g treated house Two birds treated in 81% 0.3mg/g isolation The results show that the balance of naturally occurring boron isotopes can be changed in a batch of chickens by oral administration of enriched boric acid.

For the purposes of this test considerable amounts of boron were administered and the total boron content was in fact increased; calculations show, however, that some of the boron 10 administered had been exchanged with boron already present in the chickens, and hence, lower amounts of boron could be administered, as would be more desirable, so as only to affect the isotopic boron ratio.

Other stable, naturally occurring isotopes that can be administered in low quantities without harm to animals could also be used; preferably, the isotopes selected should be capable of being readily-absorbed into the animals bodies (e.g., boron or selenium (Se74, Se76, Sue77 Sue78 Se80, Sue82)) This method is equally applicable to other farm livestock, such as, for example, cows, sheep, pigs, as well as other birds, e.g., turkeys or geese. Fruit and vegetables and other crops, such as grain, may be similarly marked, for example, by means of enriched water supply or spray treatment shortly before harvesting.

Claims

1. A method of so marking an animal or plant that a product derived therefrom may be subsequently identified, comprising administering to a living animal or plant at least one stable isotope of an element, which element is naturally present in the said animal or plant, the amount of the isotope or the relative amounts of the isotopes administered being so selected that the ratio of two isotopes of the said element to one another in the animal or plant differs from the ratio usually found in such animals or plants.

2. A method of obtaining a marked animal or plant product, comprising administering to a living animal or plant at least one stable isotope of an element, which element is naturally present in the said animal or plant, and recovering the animal product or plant product from the animal or plant, respectively, the amount of the isotope or the relative amounts of the isotopes administered being so selected that the ratio of two isotopes of the said element to one another in the animal or plant product so obtained differs from the ratio usually found in such animal products or plant products.

3. A method as claimed in claim 1 or claim 2, wherein the amount of the isotope or the relative amounts of the isotopes administered to the animal or plant are so selected that the animal or plant product will contain a desired isotopic ratio or a ratio within a desired range.

4. A method as claimed in any one of claims 1 to 3, wherein the isotope(s) is administered to the animal or plant within a short period before either the animal or the plant is slaughtered or harvested, respectively, or the product is recovered from the living animal or plant, which period is sufficient for the isotope to be absorbed and the isotopic ratio altered.

5. A method as claimed in claim 3 and claim 4, wherein the time, or intervals, at which the isotope(s) is administered is or are so selected that the animal or plant product will contain a desired isotopic ratio or a ratio within a desired range.

6. A method as claimed in any one of claims 1 to 5, wherein the animal or plant has been reared or cultivated substantially or totally without the use of artificial treatments to prevent disease or promote growth.

7. A method as claimed in any one of claims 1 to 6, wherein the isotope(s) is administered orally to an animal.

8. A method as claimed in any one of claims 2 to 7, wherein the product is an animal product which is recovered from an animal without slaughtering the said animal.

9. A method as claimed in any one of claims 2 to 7, wherein the product is an animal product which is recovered from an animal carcass after the animal has been slaughtered.

10. A method as claimed in claim 9, wherein the animal product is meat.

11. A method as claimed in claim 10, wherein the meat is poultry meat.

12. A method as claimed in any one of claims 2 to 11, wherein the amount of element administered is so selected that the total amount of the element in the recovered animal or plant product is not increased by more than 2 or 3 times its original content.

13. A method as claimed in any one of claims 1 to 12, wherein the element is boron.

14. A method as claimed in claim 13, wherein there is administered to the animal or plant a boron-containing composition in which boron10 and boronll are present in relative amounts such that the ratio of B10 to B11 is greater or smaller than that occurring naturally in the animal or plant.

15. A method as claimed in any one of claims 1 to 13, wherein there are administered to the animal or plant at least one isotope of each of two or more elements.

16. A method as claimed in claim 15, wherein there are administered to the animal or plant at least one boron isotope and at least one iron isotope.

17. A method of marking an animal product substantially as described in the Example herein.

18. A living animal or an animal carcass or a plant, when marked by a method according to claim 1.

19. An animal or plant product that has been obtained by a method according to any one of claims 2 to 17.

20. An animal product or a plant product or a living animal or an animal carcass or a plant, containing an element which would normally be present in the said animal or plant in a plurality of stable isotopic forms, wherein the relative amounts of the various stable isotopes of the element that are present differ significantly from the percentages normally found in nature.

21. The use of a living animal or plant marked by a method as claimed in claim 1, or a carcass of such an animal, to produce a marked animal or plant product that is suitable for sale for human consumption.