Method and system for verifying the age of an animal providing meat

Abstract

The invention provides a method for verifying the age of an animal providing meat using volatile profiles that comprises the step of providing a sample of animal meat. The method uses one or more chemical analyses to obtain a profile of a set of volatile organic compounds from a sample of meat from an animal. The profile is fit to a mathematically discriminating function resulting. The data obtained is analyzed in order to establish a correlation between the age of the animal (tooth development) and volatiles exuded by meat.

Claims

1. A method for verifying the age of animal meats using volatile compounds profiles comprising the steps of: obtaining a sample of meat of an animal; obtaining a homogenized sample of meat by finely cutting said sample of meat and eliminating all visible traces of fat; placing said homogenized sample meat in in a lower part of a vial having an hermetic septa and a head space; heating said vial to a temperature between 0 and 100° C. for between 1 and 500 minutes; introducing a solid-phase micro-extraction fiber into said septa of said vial; maintaining said solid-phase micro-extraction fiber in said vial's head space for at least 5 minutes; obtaining gases by desorbing in the point of injection of a gas chromatograph; separating said gases obtained in a chromatographic column using helium at a constant flow; obtaining a chromatogram having a plurality of chromatographic peaks representing volatile organic compounds; identifying said volatile organic compounds in said chromatogram; selecting a subset of said volatile organic compounds identified in said chromatogram, wherein the areas of said chromatogram corresponding to said subset are adjusted to a mathematically discriminating function; and obtaining an objective limit of tooth development of said animal using an output of said mathematically discriminating function; wherein the discriminant mathematical function comprises:
Y=6.074−0.077X.sub.1−0.046X.sub.2−0.072X.sub.3−0.068X.sub.4−0.068X.sub.5−0.043X.sub.6−0.071X.sub.7 where: Y Discriminant variable X.sub.1 Hexanoic acid X.sub.2 Octanol X.sub.3 Nonanal X.sub.4 Benzoic acid X.sub.5 Octanoic acid X.sub.6 Tridecanol X.sub.7 Tetradecanol.

2. The method of claim 1, wherein said step of heating said vial further comprising heating said vial to a temperature of 50° C. for 30 minutes.

3. The method of claim 1, wherein said step of maintaining said solid-phase micro-extraction fiber in said vial's head space further comprising maintaining said solid-phase micro-extraction fiber in said vial's head space for 30 minutes.

4. The method of claim 1, wherein if “Y” is greater than zero, then the tooth development is less than or equal to a pre-established limit of the animal's permanent teeth.

5. The method of claim 4, wherein if “Y” is less than zero, then the tooth development is greater than the pre-established limit of the animal's permanent teeth.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 (Prior Art) shows a solid-phase micro-extraction system (SPME).

(2) FIG. 2 shows a sequential diagram of the adsorption of the analytes in the fiber inserted in a vial that contains a meat sample.

(3) FIG. 3 shows a chromatogram of one of the measurements taken in this invention.

DETAILED DESCRIPTION OF THE INVENTION

(4) Since there are volatile compounds that are generated under specific age-related physiological characteristics, this invention proposes a method to determine volatile profiles exuded by types of meat, especially bovine cattle, as well as that of pigs, sheep and poultry of different ages.

(5) The solution consists of the development of an analytical technological platform, using equipment available in chemical laboratories, such as gas chromatographs. To this effect, the gas chromatography and solid-phase micro-extraction technique, known as GC-SPME, is used, a technique sparingly used in technological applications for food certification, since it has been recently developed. The volatile profiles obtained are correlated to age using a mathematical function, which generates an algorithm for the objective verification of the age of the cut up meat.

(6) As shown in FIG. 1 (prior art), the SPME technique consists of a process of extraction and pre-concentration of the sample which is done simultaneously in one sole step. It includes a short capillary column (100) open to the environment and contained in a retractable pin (101), which includes the syringe barrel (102), a central body (103) that ends in a needle (104), which contains a silica fiber (105).

(7) The SPME column (100) is a fiber covered with a phase used for extraction, which can be constituted of a polymer or an adsorbing solid, allowing a large number of volatile analytes to be retained, if applied over the head space of a sample. As shown in FIG. 2, a sample (300) is placed inside a vial (200), where this sample (300) begins to free the VOCs (step 1); after a while the VOCs are accumulated inside the vial (step 2). Subsequently, the SPME fiber (100), contained in a retractable mechanical pin (101), is inserted in a vial (200) through a septa. After the fiber is inserted in the vial (200), the retractile system exposes the fiber to the head space, adsorbing the volatiles exuded by the sample (step 3). Then, the volatiles are analyzed by gas chromatography (GC) when the SPME fiber (100) is placed in this GC (step 4).

(8) A sample of meat is placed in an HS vial (Head Space) with an airtight septa, through which the solid-phase micro-extraction fiber is introduced, which is then in contact with the vial's head space. The sample inside the vial is subjected to a thermal process within a 0-100° C. temperature range.

(9) After the adsorption of the analytes in the fiber, they are desorbed directly at the gas chromatograph port.

(10) The volatile compounds that are correlated to the animal's age or tooth development are measured and a mathematical function that associates their concentration, relative concentration, chromatographic area, relative area or partial pressure with the age of the animal or tooth development is used.

EXAMPLE OF APPLICATION

(11) Samples of fresh meat were taken (Longissimus dorsi, strip loin) from 8 groups of animals with different stages of tooth development and gender. 5 animals were sampled per group and each sample was analyzed in triplicate, obtaining 120 measurements (8×5×3=120).

(12) TABLE-US-00001 TABLE 1 Samples of Fresh Meat according to age and gender Sample group Permanent teeth Gender Group 1 1 Male Group 2 2 Male Group 3 4 Male Group 4 6 Male Group 5 2 Female Group 6 4 Female Group 7 6 Female Group 8 8 Female

(13) A 2.5 gram sample was placed in a 20 ml HS vial. The vial was sealed and heated at 50° C. for 30 minutes. A commercial 50/30 μm Divinylbenzene/Carboxen-Polydimethylsiloxane SPME type fiber was placed through the septa and kept in the vial's head space for 30 minutes. The fiber was then desorbed in the injection port of a Thermo Scientifics Trace GC Ultra gas chromatographer equipped with a quadrupole mass spectrometer (Thermo Scientifics ISQ) at 250° C. for 5 minutes (splitless mode for 5 minutes). The separation was carried out in a Restek RTX-5MS brand column, 60 meters long, using helium at a constant flow of 1.3 ml/min. The initial temperature of the chromatograph oven was 40° C. and the end temperature was 250° C. The operation of the chromatograph equipment was controlled through Finnigan Xcalibur Software (Thermo Electron Corporation).

(14) As shown in FIG. 3 and through this chromatographic procedure, a chromatogram signal was obtained with over 40 chromatographic peaks. Of these chromatographic peaks, 17 were identified with a mass spectrometer and were confirmed with chemical standards:

(15) TABLE-US-00002 TABLE 2 Identification of Compounds using spectrometry Retention time Compounds 12.83 n-Pentanol 17.63 n-hexanol 21.78 Benzaldehyde 22.42 Hexanoic acid 24.32 2-ethyl-1hexanol 25.83 Octanol 26.95 Nonanal 28.87 Benzoic acid 29.00 Octanoic acid 30.15 Decanal 31.84 Nonanoic acid 32.79 Tridecanol 35.47 Tetradecanol 36.85 4-Formil, benzoic acid 38.00 Pentadecanol 40.38 Hexadecanol 42.69 Heptadecanol

(16) Of these 17 compounds, 7 VOCs were selected and their relative areas were adjusted to a discriminating mathematical function to verify an objective limit of tooth development. In this example, the limit of 4 permanent teeth was used, which corresponds to type V meats for Chilean categorization. A precision above 90% was obtained.

(17) Categorization Algorithm for Type V Fresh Meat

(18) Discriminant Mathematical Function
Y=6.074−0.077X.sub.1−0.046X.sub.2−0.072X.sub.3−0.068X.sub.4−0.068X.sub.5−0.043X.sub.6−0.071X.sub.7
Decision Rule

(19) If Y>0 tooth development less than or equal to 4 permanent teeth (type V meat).

(20) If Y<0 tooth development more than 4 permanent teeth

(21) Nomenclature

(22) TABLE-US-00003 Y Discriminant Variable X.sub.1 Hexanoic acid X.sub.2 Octanol X.sub.3 Nonanal X.sub.4 Benzoic Acid X.sub.5 Octanoic Acid X.sub.6 Tridecanol X.sub.7 Tetradecanol

(23) TABLE-US-00004 TABLE 3 Detail of the precision of the discriminant algorithm Discriminated as Less than or Sample equal to 4 teeth Over 4 teeth Total Accuracy Type V meat 70 5 75 93.30% Other types 4 41 45 91.10% Total 74 46 120 92.50%