Every coffee bean needs to be screened, graded and tested. Why?

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Ochratoxin A (Ochratoxin A) is a secondary metabolite secreted by Penicillium and Aspergillus. It has nephrotoxicity, immunosuppression, carcinogenicity and so on. Ochratoxin is ubiquitous in nature, in which soybeans, peanuts, corn, coffee beans and other agricultural products are easily contaminated by ochratoxin if they are not preserved properly in a high-temperature and humid environment. Ochratoxin accumulates in the human body, may cause kidney, liver and other diseases. Therefore, if there are people who often drink a lot of coffee, you should pay special attention to it.

However, from the coffee bean processing process, the coffee fruit after processing to the raw bean water content is only 12%, and the roasted ripe beans, the moisture content is less than 5%, stored in the dry state, not easy to mildew. However, if coffee beans are damp or improperly stored during shipping, there is still a risk of ochratoxin production.

The large domestic coffee importers all have coffee storage space, and the warehouse where a large number of raw beans are stored is at least three stories high, the purpose is to maintain good ventilation, and in case of rainy season, there are special personnel responsible for maintaining storage humidity and maintaining the quality of coffee beans.

As for the problem of pesticide residues in coffee beans, most of them are poor and backward countries, the application of pesticides by farmers is not in line with economic benefits, and the probability of pesticide residues in coffee fruits after processing is very low. According to the results of coffee sampling tests conducted by the Food and Drug Department over the years, the failure rate is very low.

However, some people in the coffee industry have revealed that the coffee border inspection is a "sampling", not batch-by-batch inspection, and it is still possible to drink defective beans with bad luck. Therefore, after buying raw beans, many operators will conduct manual screening before baking to ensure the quality of the beans. Some people may even think that the bulk commercial coffee beans that have not been manually screened are more likely to be mixed with defective beans and the quality is relatively poor.

The concept of "picking beans by hand is good coffee" does not apply to the general public. Generally speaking, coffee that needs to pick beans manually is usually tasted as fine coffee produced in small quantities, as well as coffee used for testing when participating in coffee competitions. In general, coffee beans are "graded" (grading) according to their origin, factory height, particle size and the number of imperfections in the sample (including broken beans, pebbles or branches, etc.).

And now the automatic screening of coffee beans has improved from the use of infrared identification to the color sorting machine. After the raw beans enter the guide trough, the color selection machine will blow out the defective beans that do not conform to the color setting from the bean stream, and the beans that have been selected by color will also be screened manually through the conveyor belt to pick out obvious defective beans. Therefore, when selecting beans, manufacturers only need to confirm whether the sample beans meet the classification, because the graded beans naturally have the corresponding quality, and there is no need to worry too much when baking and drinking them later.