WO2002049939A1

WO2002049939A1 - Method of sampling and an associated product

Info

Publication number: WO2002049939A1
Application number: PCT/NZ2001/000295
Authority: WO
Inventors: Michael Lewis Tate
Original assignee: Agresearch Limited; Lingard Label Company
Priority date: 2000-12-21
Filing date: 2001-12-21
Publication date: 2002-06-27
Also published as: AR031959A1; AU2002216508A1; UY27096A1

Abstract

The present invention relates to a method of sampling a foodstuff by combining in a food package, food and a sample capture device, a drip pad (1) configured to retain a sample from the food in a form suitable for subsequent analysis. The drip pad (1) includes an absrobent material that is divided in punched out areas (3) to avoid lateral flow of sample captured in the sample area (4). There is a backing strip (5) underneath the pad made of fluid impervious material.

Description

METHOD OF SAMPLING AND AN ASSOCIATED PRODUCT

TECHNICAL FIELD

This invention relates to a method of sampling and an associated product.

Reference throughout this specification will be made to use of the present invention in relation to the sampling of foodstuffs.

BACKGROUND ART

In order to gain market access and premiums, food retailers and producers need to provide information and guarantees concerning the origin, and processing history of food. For example, there is considerable consumer concern about the transmission of diseases (such as BSE) through meat products. Further, there is considerable consumer concern about the introduction of genetically modified foods and the desire to know where these foods originated.

However, when primary food items are reduced into saleable portions, the exact origin of the material is often lost which means specific product information and potential value is lost.

There are three primary reasons for this

a) Practicality; a single animal or plant can be broken down into ten, hundreds even thousands of separate saleable portions and transferring a label to each is not economic.

b) Food Hygiene; a transferred label can carry contamination which could be transferred onto the final foodstuff.

c) Food Safety; it is possible the label mistakenly cooked or eaten along with the product. This problem is particularly acute with food products that are cut into very small portions, diced or minced as part of the processing chain.

There are systems in common use which replicate labels down a product chain using barcodes or trace food products by sequence or batch production. While these systems work with large food items which can be separately labelled, as discussed above the cost of labelling small or low value items is prohibitive.

Recently systems which have been developed that take DNA samples from the animal or plant in its entire form, for example a live animal or carcass. For example, the applicant has developed a cost effective method of sampling DNA from a carcass or primary food item and this is described in Patent Application No. PCT/NZOO/00050. However, up until now there has not been developed a system or product that can really be implemented to link saleable portions derived from that carcass or primary food product to the processed product.

All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.

It is an object of the present invention to address the above problems, or at least provide the public an useful choice.

Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only. DISCLOSURE OF INVENTION

According to one aspect of the present invention there is provided a method of sampling a foodstuff, characterised by

combining in a food package, food and a sample capture device configured to retain a sample from the food in a form suitable for subsequent analysis.

The term "foodstuff should be taken to mean any food product.

Reference throughout this specification shall now be made to the foodstuff as being meat. However, it should be appreciated that the present invention can apply to other foodstuffs including plant material, fungi and the like.

The term "food package" should be taken to mean any container or packaging for food. Most likely the food package would be of a size and configuration which is commonly used to contain food sold in a retail situation. Reference throughout this specification shall now be made to the food package in the form of a meat tray. However, this should not be seen as a limitation on the present invention in any way.

The term "sample" should be taken to mean a representative sample of the food including some or all constituents of the food, including but not limited to DNA, RNA, carbohydrates, fats, protein, bacteria, metabolites and chemical residues.

In preferred embodiments, the present invention may be used for taking a sample of genetic material such as DNA from a meat product.

The DNA can then be used to establish the identity of a meat product, trace the meat product back through the processing history to its origin, or to determine the presence or absence of genetic modification.

However, this should not be seen as a limitation on the present invention in any way which can be used for the sampling and subsequent analysis of a range of food constituents or contaminants, substantially as described above.

For example, the present invention also enables meat products to be tested for bacterial contamination, chemical residues such as organic and/or inorganic contaminants, or metabolites such as growth promotants. The present invention could also be used to verify that a food product contained a given level of bioactive properties or essential nutrients if marketed as such.

According to another aspect of the present invention there is provided a method of sampling a foodstuff,

characterised by the initial steps of

a) sampling a primary product from which a foodstuff is derived,

b) recording a batch number which relates to the primary product, and

c) marking the batch number onto a sample capture device to be associated with the foodstuff.

According to a further aspect of the present invention there is provided a sample capture device for use in a food package as described above.

The sample capture device may take a number of forms.

In one preferred embodiment of the present invention the sample capture device may include a food grade adhesive which retains a sample from the food. For example, there may be placed an adhesive strip at the bottom of the meat tray or inside the overwrap so that the meat is placed in contact with it. When the meat is removed, a small sample of the meat tissue adheres to that strip.

As one preferred usage of the present invention is the DNA tracing of a meat sample, it is essential that the adhesive does not interfere with the chemistry of DNA analysis or storage of the sample. It should be appreciated that many glue residues interfere with sample analysis and storage and as such are not appropriate for use with the present invention. As such, DNA sampling products previously available have always been constructed so that any adhesives or chemical binders are kept remote from the sampling area to avoid contamination.

As the adhesive is in contact with a food product, it is also essential that the adhesive used will comply with food safety regulations to ensure that any residue from the adhesive does not pose a threat to public health and is suitable for direct contact with fatty and aqueous foodstuffs.

The adhesive layer may remove a sample of cellular material by direct adhesion and/or may have absorbent properties to facilitate the absorption of cells into the adhesive.

In another embodiment the sample capture device may have an abrasive surface which naturally collects samples from food placed on it by virtue of samples either falling off the food or being actively removed as a consequence of the food moving over the surface of the capture device.

A further preferred embodiment of the sample capture device may include an absorbent material. Thus, it is envisioned that in the embodiments of the present invention where the food is meat, the sample capture device may be absorbent paper which can absorb meat juices.

In some embodiments of the present invention the sample capture device may incorporate one and or any of these forms of sample collection in the sample capture device.

In other preferred embodiments of the present invention the sample capture device may also be impregnated with chemicals, for example to extend the storage time of the sample or to prevent bacterial growth. In other embodiments, the chemical may be an enzyme or enzymes which act to facilitate the removal of cellular material by solubilising the outer layer of the tissue.

Reference throughout this specification should now be made to the sample capture device as being a "drip pad". Again, this should not been seen as a limiting description.

Drip pads for meat trays are well known. Some of these contain gels to absorb excess fluid, others contain absorbent fibres, for example, sphagnum moss, viscose fibres or polyethylene. However, many of these would be unsuitable for use with the present invention. This is because it is desired for the present invention to retain a food sample in a fullproof manner for later analysis.

It should be noted that often in a food package there could be placed a number of food items which come from a number of sources. For example, they may be provided meat cuts from different carcasses. Thus using a standard drip pad, the blood or juices from the various cuts may mingle, making it uncertain as to which meat cuts relate to which samples captured by the drip pad.

Therefore in preferred embodiments the drip pad is constructed so that it has a number of samples areas distinct from each other which minimise lateral flow of the food sample from one area to another. One way of achieving this is to have holes punched through at selective places in the drip pad.

Further, to make analysis easier it is envisioned that the drip pad may have sample areas spaced as so to fit exactly into the wells into a standard microtitre laboratory plate, for example, a 96 well microtitre laboratory plate. In other embodiments the sample areas may be configured to fit other laboratory ware, for example 384 well microtitre plates and the like. In preferred embodiments, the drip pad has the following qualities:

a) It can protect, store and present the food portions for sale

b) It can absorb excess fluid from the product

c) It can be posted safely by mail

d) It has sample areas which are separate, so that a food sample taken from the material above the sample area does not travel laterally into other sample areas

e) It has sample areas spaced to fit common formats of laboratory ware.

A food package in accordance with the present invention may also include a kit with instractions and means by which the drip pad can be readily sent for analysis. For example there may be provided a liquid impervious bag with a pre-printed address on. Alternatively the drip pad may have adhesive borders enabling the drip pad to be folded over and adhered to itself. The pad itself then can possibly be sent without extra packaging.

Part of the present invention is the system by which traceability can occur.

One aspect of the present invention is the ability to label the source of products in a cost effective manner by conducting sampling of the primary product and having a sample capture device associated with each saleable item which includes the batch number of the primary product which was sampled.

A specific example of how a saleable product is prepared is described below:

a) Production batches (Bins) of up to 200 carcasses are identified in the processing plant and QA systems are put into place to ensure carcasses are accurately placed in a batch.

b) A sample is taken from each carcass using the sampling method disclosed in Patent Application No. PCT/NZOO/00050 and information is stored as to which carcass contributes to each batch.

c) Batch numbers and/or a date time stamp are printed or pre-printed onto each drip pad.

d) As a processed product is placed into its retail packing a printed drip pad as described above is placed under the meat.

e) The cuts are placed in a single layer or if overlapping so that each cut contacts the drip pad directly in one area.

f) The product is then sent to the market.

A further aspect of the present invention is the ability to provide a DNA trace from the saleable product.

It is envisioned that the following is by one means by which this can be achieved.

In one embodiment the drip pad made be made out of a cloth sold under the name Kinocloth™ manufactured by Honshu Kinocloth Co Ltd, Tokyo, Japan. This is comprised of 100% wood pulp fibres bonded into a lint free non-woven cloth with a chemical binder. The ideal construction is a food grade 1.2mm cloth capable of absorbing 20 times its own weight while retaining its structural strength.

In some embodiments the sampling cloths may have a backing strip onto which is printed text and a barcode identifying the production batch. In some embodiments the backing strip may be impervious to fluid, thus preventing any sample captured in the cloth from draining out into the rest of the meat tray.

The drip pad may then be sent to the laboratory, possibly using a kit supplied with the food package. The laboratory can then transfer samples from the drip pad into the laboratory ware which matches the separated sample areas on the pad. The laboratory retrieves uses all samples from carcasses contributing to the batch.

Then the DNA analysis is conducted on each of the 96 sample areas of the backing sheet sample and the DNA matched to one or more of the carcasses from the batch in question. In addition or alternatively the samples from the carcass of origin and the product tray can be analyzed for presence of contamination with chemical residues, the existence of specific genes or transgenes and or bacteria and specific bacterial strains (eg: E. coli).

The present invention has a number of advantages over the prior art.

One advantage is that there is provided an effective system for DNA traceability which is efficient and fits into current processing practices. The idea of substituting a sample capture device for a standard device used in meat packaging (such as a drip pad) assists.

No special labels or barcodes are required over and above the provision of a drip pad, and thus the cost of labeling is low.

The efficiency of the system and incorporation into a pre-existing component is important in that it adds little extra cost in food industries that are typically low margin.

In addition because it does not add a new step in the processing chain uptake is easier.

The invention facilitates safer food systems by providing simple and effective method of sampling all food. This provides the customer with the option of getting an independent third party to verify the origin of food products, the presence and origin of any contaminating bacteria, GMO, chemical residues, and/or claimed levels of bioactivity or essential nutrients. This allows widespread independent auditing of the food chain, promoting safe practice and integrity in the food supply chain.

BRIEF DESCRIPTION OF DRAWINGS

Further aspects of the present invention will become apparent from the following description which is given by way of example only and with reference to the accompanying drawings in which:

Figure 1 is a diagrammatic view of a drip pad in accordance with one embodiment of the present invention.

BEST MODES FOR CARRYING OUT THE INVENTION

Figure 1 demonstrates the drip pad generally indicated by arrow 1.

The drip pad (1) includes a absorbent material to in the form of KinoCloth™.

The KinoCloth™ (2) is divided so is punched out in areas (3) to avoid lateral flow of samples captured in the sample area (4).

The sample area (4) is positioned so that they can be fitted exactly into the wells of a standard 96 well mircotitre laboratory plate.

Underneath the KinoCloth™ (2) is a backing strip (5) which is made of a fluid impervious material. The text and barcode identifying the batch of production is recorded there.

Specific embodiments of the present invention are discussed below. Example 1

BACKGROUND

Six fabrics from Honsu-Kinocloth were tested for absorbency, ease of handling during processing and performance in DNA tests:

Fabric Weight (g/m²) Thickness (mm)

KSG40 40 1.0

PL40 40 0.7

PB40 40 0.7

B-SAP85 85 1.1

TDS 170 2.0

NF4

The physical characteristics of KSG40, PL40 and PB40 make these preferable for the proposed application.

Key features distinguishing these fabrics were

• highly absorbent, at least 1ml of blood per square cm

• dries rapidly (1 hour) once removed from wet substrate, ^•

• maintain their structure during prolonged wetting (2 months)

• maintain structure during DNA extraction and washing procedures such as the use of boiling caustic soda and detergent washes

DNA suitable for PCR can be successfully recovered from the blood or tissue fluids absorbed by the fabric The other cloths failed on some or all of these points

Honsu KinoCloth KSG40, a non-woven cotton fibre fabric, was chosen as the preferred substrate.

This cloth was placed in contact with blood and meat and tested under several storage regimes: room temperature (blood and meat allowed to dry), 4 degrees Celsius (moist) and frozen.

Under all conditions the cloth maintained structural integrity. DNA profiles were also obtained from sixty samples stored for 6 months. The DNA analysis methods were standard forensic extraction and PCR methods well known in the art.

Example 2

BACKGROUND

Meat was purchased from a retail outlet. The meat was then un-wrapped and 5cm patches of a polypropylene label coated with acrylic adhesives were placed onto the leg of lamb. Adhesives were left in contact with the meat from 2 hours to 2 weeks.

Immediately after removal, the patches were folded into two so that the two adhesive surfaces stuck together sandwiching sample bonded to the adhesive between the backing sheet.

The samples were stored at room temperature until extraction took place.

To extract DNA, a 2mm diameter punch was taken from the folded sampling strip and placed in a 1.5ml microtube. DNA was extracted by boiling the sample in a strong base such as caustic soda (NaOH).

Preferred glue product:

Avery Dennison S2800 food contact product The properties that distinguished this glue were

1. food approved

2. removed less than 0.2 mm layer of tissue without materially damaging the food

3. maintained its ability to remove tissue consistently even after long term contact with wet and fatty food

4. did not damage or taint the food

5. the glue was substantially removed by standard DNA extraction procedures and residue did not interfere with PCR process.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof as defined in the appended claims.

Claims

WHAT WE CLAIM IS;

1. A method of sampling a foodstuff by combining in a food package, food and a sample capture device configured to retain a sample from the food in a form suitable for subsequent analysis.

2. A method as claimed in claim 1 wherein the sample includes a representative sample of the food including some or all constituents of the food, and specifically DNA, RNA, carbohydrates, fats, protein, bacteria, metabolites and/or chemical residues.

3. A method as claimed in claim 1 or claim 2 wherein the food package is in the form of a tray.

4. A method as claimed in claim 3 wherein the food package is in the form of a meat tray.

5. A method as claimed in any one of claims 1 to 4 wherein the sample capture device includes a food grade adhesive to retain the sample.

6. A method as claimed in any one of claims 1 to 5 wherein the sample capture device has an abrasive surface to retain the sample.

7. A method as claimed in any one of claims 1 to 6 wherein the sample capture device includes an absorbent material to retain the sample.

8. A method as claimed in any one of claims 1 to 7 wherein the sample capture device has a number of distinct sample areas.

9. A method as claimed in any one of claims 1 to 8 wherein the sample capture device has holes punched through it at selective places, forming distinct sample areas.

10. A method as claimed in any one of claims 1 to 9 wherein the sample capture device has sample areas spaced to fit into the wells of a standard microtitre laboratory plate.

11. A method as claimed in any one of claims 1 to 10 wherein the absorbent material of the sample capture device is made of Kinocloth™.

12. A method as claimed in any one of claims 1 to 11 wherein the sample capture device has a backing strip onto which an identifying code can be printed.

13. A method of sampling a foodstuff as claimed in any one of claims 1 to 12 which includes the initial steps of:

sampling a primary product from which a foodstuff is derived,

recording a batch number which relates to the primary product, and

marking the batch number onto a sample capture device to be associated with the foodstuff.

14. A method as claimed in any one of claims 1 to 13 wherein the marking of the sample capture device includes batch numbers and/or a date time stamp preprinted onto each sample capture device.

15. A sample capture device for use in a method as claimed in any one of claims 1 to 14.

16. Food packaging for use in a method as claimed in any one of claims 1 to 14.

17. A kitset for use in a method as claimed in any one of claims 1 to 14, including

food packaging,

a sample capture device , and instructions and means by which the sample capture device can be readily sent for analysis.

18. A method for sampling a foodstuff substantially as described herein with reference to and as illustrated by the accompanying examples and drawings.

19. A sample capture device substantially as described herein with reference to and as illustrated by the accompanying examples and drawings.

20. Food packaging substantially as described herein with reference to and as illustrated by the accompanying examples and drawings.

21. A kitset substantially as described herein with reference to and as illustrated by the accompanying examples and drawings.