Three ways to keep grain fresh for a long time by storing grain scientifically

At present, the supply of grain market is very abundant, and consumers can buy the finished grain they need at any time. However, some consumers are worried that the grain in circulation on the market will be old grain. Can the quality and safety of grain be fully guaranteed?

A few days ago, a reporter from the Economic Daily learned in an in-depth investigation that there are both new and old grain in circulation on the market. In order to ensure the food safety of consumers, grain depots at all levels throughout the country and grain processing enterprises have widely adopted advanced grain storage technology to effectively solve the problem of mildew prevention and pest prevention in grain storage and ensure that the grain reserves are always fresh.

Three ways of grain storage

In order to ensure the quality of rotation grain, the central reserve grain must be tested before rotation, and only those whose quality meets the standard can be rotated.

After the new grain is put on the market every year, our country mainly stores it through three ways: policy grain storage, enterprise turnover grain storage and farmers' grain storage.

At present, Chinese farmers store more than 500 billion jin of grain every year, accounting for about 50% of the country's total grain output. The grain stored by farmers is mainly used for self-consumption, and some new agricultural operators such as large grain growers and family farms with grain storage facilities generally store grain in stages and maximize profits as much as possible through sales at the wrong time.

The turnover and storage of grain in enterprises is mainly to meet the needs of grain processing. Every year, as soon as the new grain is on the market, grain processing enterprises will purchase new grain according to the market price and store it. The longest grain storage period is one year, and the stored grain will be continuously processed and put into the market before the new grain is listed. In recent years, due to a variety of factors, grain processing enterprises are generally difficult to operate. In order to reduce storage costs, some grain processing enterprises have reduced the amount of grain purchased, and they often get part of the grain source through competitive trading in the grain wholesale market.

At present, part of the grain in circulation on the market comes from policy-based grain reserves, which is composed of national grain reserves and state temporary grain reserves, with a storage period of more than one year.

The national grain reserves are divided into central grain reserves and local grain reserves, the central grain reserves belong to the central government, the local grain reserves are divided into provincial, municipal and county levels, and the grain rights are vested in the localities. In order to ensure the quality and storage safety of the stored grain, the stored grain should be rotated out of the warehouse regularly, and the rotation time varies according to different regions. In accordance with the measures for the rotation Management of Central Grain and Oil reserves (for trial implementation), the storage life of central grain reserves is calculated on the basis of production time, which varies according to different regions. In the south of the Yangtze River, the storage life of rice is 2 to 3 years, wheat is 3 to 4 years, corn is 1 to 2 years, beans is 1 to 2 years, and to the north of the Yangtze River, rice is 2 to 3 years, wheat is 3 to 5 years, corn is 2 to 3 years, and legumes are 1 to 2 years. In order to ensure the quality of the rotation grain, the central reserve grain must be tested before rotation, and only those whose quality meets the standard can be rotated.

Old grain is not aged grain.

With the extension of storage time, especially after exceeding the normal storage life, even if there is no fever, insect and mildew, grain still has the natural phenomenon of aging.

How to effectively distinguish between new grain, old grain and aged grain? Is the old grain the aged grain?

Experts told reporters that old grain is not a standard term for the grain industry, but a general term for non-newly produced grain in society. Aged grain refers to rice, wheat and corn, which are not suitable for direct consumption as rations, and do not include finished grain. Aging, suitable for storage and unsuitable for storage belong to grain storage quality indicators, while mycotoxins, pesticide residues and heavy metal contents belong to food safety indicators. The storage quality index and the food safety index are two independent systems, the former is used to judge whether the grain is still suitable for storage, and the latter is used to judge whether the grain is toxic or harmful. Not suitable for storage or aging does not mean that it can not be eaten, the key depends on whether the food safety index exceeds the standard.

It is understood that before 2007, the grain storage quality judgment rules divided the grain and oil storage quality into suitable storage grain and oil, unsuitable storage grain and oil and aged grain and oil. In 2007, the relevant state departments jointly issued the Circular on the implementation of the National Standards for the determination of Grain Storage quality, adjusting the storage quality indicators of rice, corn and wheat to suitable storage, mild storage and severe storage. The concept of aged grain was thus abolished.

Experts say that grain aging is a natural phenomenon. Grain is alive, with the extension of storage time, especially after exceeding the normal storage life, even if there is no fever, worms and mildew, there is still a natural phenomenon of aging, which is mainly manifested as the decline of edible quality and use quality. the color, smell and taste deteriorated obviously during severe aging. Whether the grain is aged or not is mainly determined by the edible quality indexes such as color, smell, taste, fatty acid value and so on. Whether the grain can be eaten by human beings should be judged by the hygienic index, not by the storage quality. Non-aged grain that does not meet the requirements of health indicators is also not edible.

Storage technology continues to improve

With the continuous upgrading of grain storage technology, the concept of grain storage in China is changing and is developing towards "green, ecological, intelligent and efficient" ecological grain storage.

With the progress of grain storage technology, the quality of grain storage in China has been significantly improved. The reporter learned in the interview that the "four-in-one" grain storage technology of mechanical ventilation, recirculation fumigation, grain cooling, and grain situation monitoring has been widely used in central grain depots, local grain depots at all levels, and grain processing enterprises throughout the country, effectively solving the problems of mildew prevention and pest control in grain storage. It is estimated that after adopting this technology, the loss rate of central grain reserves has been reduced from 4% to less than 1%, the suitable storage rate has increased from 70% to 99%, and the use of stored grain chemicals has been reduced by 80%.

Seamless supervision of stored grain is an important means to ensure the quality of grain storage. GE Liang, deputy director of Anhui Modern Grain Logistics Center, told reporters that before, during, and during grain storage, grain quality and storage quality should be strictly tested. In order to ensure that the grain in storage is new grain, during the period of grain purchase, it is necessary to carry out strict closed inspection of grain in storage and strictly guard against "human grain." the storekeeper has doubts about the quality of grain in storage and can refuse to put grain in doubt at any time. In order to ensure the quality and safety of stored grain, they adopted the method of timing rotation to speed up the pace of grain rotation and ensure that the grain reserves are always fresh.

With the continuous upgrading of grain storage technology, the concept of grain storage in China is changing and is transforming to ecological grain storage.

It is understood that central and local grain depots, as well as some enterprise grain depots, are now widely promoting the use of non-chemical drug prevention and control technologies to reduce the use of stored grain chemicals. The China National Grain Reserve Management Corporation has popularized the technologies of heat insulation and cold preservation, under-film circulation ventilation and slow-release ventilation in the directly affiliated warehouses in Northeast, Northwest and North China, and achieved good results.