Method for estimating production location

1. A geographical origin estimation method comprising:

measuring a stable isotope ratio of carbon contained in a measurement target object collected from an animal;

measuring a stable isotope ratio of a constituent element of water contained in the measurement target object; and

estimating an area where the animal has grown based on the stable isotope ratio of carbon and the stable isotope ratio of the constituent element of water;

wherein estimating the area where the animal has grown comprises:

estimating a rough area where the animal has grown from the stable isotope ratio of the constituent element of water;

estimating feed used to grow the animal from the stable isotope ratio of carbon; and

narrowing down the rough area to an area using the feed estimated from the stable isotope ratio of carbon; and

estimating that the area using the feed is the area where the animal has grown; and

wherein estimating the rough area comprises estimating the rough area from the stable isotope ratio of the constituent element of water according to an equation, the equation indicating a relationship between a difference Δδ and a stable isotope ratio δD, the difference Δδ being between a stable isotope ratio of a constituent element of water contained in precipitation at a predetermined reference point and a stable isotope ratio of a constituent element of water contained in precipitation in an estimation target area, and the stable isotope ratio δD being of a constituent element of water contained in a measurement target object collected from an animal having grown in the estimation target area.

2. The geographical origin estimation method according to claim 1 , wherein measuring the stable isotope ratio of carbon contained in the measurement target object comprises:

washing the measurement target object with a neutral detergent;

drying the measurement target object after washing the measurement target object;

performing a degreasing process by dipping the measurement target object in ethanol after drying the measurement target object; and

measuring the stable isotope ratio of carbon contained in the measurement target object after the degreasing process.

3. The geographical origin estimation method according to claim 1 , wherein measuring the stable isotope ratio of the constituent element of water contained in the measurement target object comprises:

freeze-drying the measurement target object; and

measuring the stable isotope ratio of the constituent element of water contained in the measurement target object while the measurement target object is freeze-dried.

4. The geographical origin estimation method according to claim 1 , wherein the equation is:

δ D= 1.41×Δδ+198.

5. The geographical origin estimation method according to claim 1 , wherein measuring the stable isotope ratio of carbon or measuring the stable isotope ratio of the constituent element of water comprises using a laser spectroscopic stable isotope ratio analyzer configured to:

analyze a stable isotope ratio of carbon or the constituent element of water contained in the measurement target object by irradiating a carbon dioxide gas and water vapor generated by burning the measurement target object with a laser beam; and

analyzing an absorption amount of the laser beam.

6. The geographical origin estimation method according to claim 1 , wherein the measurement target object is animal hair.

7. The geographical origin estimation method according to claim 1 , wherein the measurement target object is hair of a cashmere goat.

8. The geographical origin estimation method according to claim 1 , wherein the constituent element of water is hydrogen.

9. The geographical origin estimation method according to claim 1 , wherein the constituent element of water is oxygen.