World Food Day: How to store food?

1.
What are stored grain pests?Common stored grain pests include corn weevil, big grain pirate, rust red flat grain pirate, red grain pirate, grain beetle, Indian grain moth and so on
.
There are roughly three sources: one is that the pests and eggs are infected when the grain is harvested; the second is that there are already pests and eggs of the grain tools and equipment; the third is that the pests are infected during the storage period
.
Some pests lay their eggs on the ears of crops such as rice, wheat, corn, beans, etc.
that have not yet been harvested.
The hatched larvae then penetrate into the grains to feed on, grow and develop, and enter with the harvested grains.
The storage link is not easy to be found within 1 to 2 months of storage.
As a result, offspring and grandchildren reproduce, and the number of pests in the food will continue to increase, causing harm
.
2.
What are the simple methods for preventing insects in stored grain?(1) Zanthoxylum bungeanum pest control: Wrap 50 grams of Zanthoxylum bungeanum with clean gauze and place it in the middle of the tank for storing wheat or rice (each 50 grams of Zanthoxylum bungeanum can store 200 kg of wheat or rice) to prevent insects
.
(2) Liquor grain storage: Put a wine bottle containing 100 grams of liquor, tie the mouth of the bottle with gauze, and put it into a depth of 30 cm from the bottom of the tank, and fill it with grain
.
(3) Grain storage with grapefruit skin: Peel off the yellow-green skin of grapefruit with a knife, dry it in time and set aside
.
Put 1 kg of dried grapefruit peel per 50 kg in various beans, mix well, cover and airtightly smoke to kill pests
.
Check and flip once every 3 months, there will be no insects within one year, and it is safe to eat
.
(4) Litsea cubeba (or oil) pest control: Put the grain in a tank, altar or pot that is convenient for airtightness, and grind the Litsea cubeba into a fine powder.
It is better to use Litsea cubeba oil (available in Chinese medicine shops).
The small dishes are installed, put on the grain surface of the container, and then the container is sealed for several days, and then the lid is opened to release the air
.
After taking out the Litsea cubeba, store it in an airtight manner, and the grain will not grow insects
.
(5) Insect control of calamus and wormwood: Take fresh calamus and wormwood, wash and dry, and place three layers on top, middle and bottom for every 500 kilograms of grain to achieve the effect of repelling and killing insects.

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(6) Insect control of willow leaves, tsubaki leaves, houttuynia cordata, and mugwort powder: dried willow leaves, tsubaki leaves, houttuynia cordata, and mugwort powder are dried and mixed and ground into powder.
A small amount of household food is stored in the surface layer.
Sprinkle a layer of mixed powder in an appropriate amount to keep the grain free of insects and have a strong repellent effect on external pests
.
3.
What are the household simple insect-proof methods for rice?(1) Ventilation and bran removal method: The weather changes greatly in summer, and the rice bran is prone to sticky, causing insects.
After the summer, the stored rice can be sieved again to remove the fine bran.
Store in a ventilated place to avoid insects
.
(2) Zanthoxylum bungeanum pest control method: Pack 50g of Zanthoxylum bungeanum powder in a small cloth bag, put it in a rice jar, and seal the mouth of the cylinder with plastic film
.
The volatile substances released by Zanthoxylum bungeanum in the sealed tank can prevent insects and insects .
(3) Garlic pest control method: Garlic contains allicin, so burying garlic in rice can prevent pests
.
(4) Orange peel insect control method: Orange peel contains citral, and orange peel is buried in rice to repel insects and prevent insects
.
(5) Frozen pest control method: Put the worm-bearing rice in a plastic bag, tie the bag tightly, and place it in the freezer compartment of the refrigerator.
Take it out after 48 hours to kill the worms in the rice
.
　　4.
How to store rice in the family? 　　When storing rice in household rice jars, dry the container thoroughly, then put the rice in and cover it
.
It can be packed in a Coke bottle when the amount is small, and placed in a dry and ventilated place, avoiding high temperature and light
.
The long-term storage of rice is prone to deterioration, the color of the deteriorated rice becomes darker, the fragrance disappears, the acidity of the bran appears, the acidity increases, the viscosity of the rice decreases, the porridge does not thicken the soup, and the eating quality decreases
.
Don't buy too much rice at one time, especially in summer
.
If you buy anaerobic packaged rice, consume it as soon as possible after opening the bag
.
　　5.
What are food microorganisms? 　　Microorganisms attached to grain, we call it grain microbes
.
So, what is a microorganism? In layman's terms, microorganisms are low-level organisms that are tiny, simple in structure, and indistinguishable from the naked eye.

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In fact, except for animals and plants, all living things in nature are microorganisms
.
At present, there are tens of thousands of microorganisms that have been discovered.
For example, the well-known bacteria, viruses, molds, yeasts, etc.
, are all microorganisms
.
In addition, fungus, mushrooms, etc.
are also microorganisms, and they are some relatively advanced fungi
.
Since microorganisms are biological, they have some biological characteristics, such as growth, reproduction, metabolism and other life activities under suitable conditions
.
　　Many microorganisms are beneficial to humans
.
For example, people use the fermentation of microorganisms to make food and industrial raw materials, and can also make fermented feed, bacterial fertilizer, antibiotics, and so on
.
There are also some microorganisms that are harmful to humans.
They can cause diseases of humans, animals and plants, endanger the health of humans and animals, and bring harm to agricultural production
.
Microorganisms can also make daily necessities moldy and spoilage
.
For example, some microorganisms in stored grain can cause heat and mildew of grain and its products under certain conditions.
Due to the rapid reproduction speed of microorganisms and strong metabolism, the damage is not easy to be detected in the initial stage, which often results in serious loss of the quality of stored grain.
Even the food completely loses its use value
.
Therefore, the threat of food microbes to the security of grain storage cannot be ignored
.
　　6.
How do I know if the food contains mycotoxins? 　　Moldy grains may be contaminated by mycotoxins
.
If you want to know exactly whether the grain is poisonous, how much the poison is, and whether it can continue to be eaten, you must take samples and send them to the grain inspection department for inspection
.
It is impossible to determine whether food is poisonous based on experience and naked eyes
.
　　7.
What are the symptoms of mildew? 　　The mildewing process of rice is generally to "sweat" first, the rice grains become "strength" (white lines are formed at the grooves), and then the bran is removed, the luster is lost, the surface is gray and white, and a layer of fine powder is attached.
, Giving off a slight musty odor
.
At this time, there is no significant variation in the taste of the rice quality.
If it continues to develop, the water content will increase, the rice grains will become soft, molds multiply, and produce various colors (white, yellowish, green, purple, tan, black).
It emits a peculiar smell and finally rots
.
　　8.
Why does rice become moldy? 　　Rice is rich in nutrients such as carbohydrates, proteins, fats, vitamins and inorganic salts, and is a good natural culture medium for microorganisms
.
When the external temperature, humidity and other environmental conditions meet the needs of microbial growth, the microbes will grow and multiply in the rice
.
The growth activity of microorganisms on rice will decompose and utilize various nutrients in rice, destroy the structure of rice, and make rice lose its utilization and processing value.
At the same time, the metabolic activity of microorganisms will also secrete various toxic metabolites
.
Therefore, to ensure the safety of rice storage, it is necessary to control the activities of microorganisms in it
.
　　9.
How to judge and prevent rice mildew? 　　Contaminated rice with edible fungi may cause serious poisoning
.
The following methods can determine and prevent mold contamination
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(1) Sensory color and taste judgment: The surface of moldy rice is light yellow, light gray or green, and its texture becomes soft and easy to crush.
At the same time, a musty smell can be smelled, and moldy rice cannot be eaten
.
(2) Anti-mold: A closed environment with humidity and poor ventilation is conducive to mold reproduction and toxin production
.
Therefore, when storing rice at home, the most important thing is to pay attention to ventilation and moisture
.
　　10.
Can the discolored rice still be eaten? 　　Normal rice is golden or light yellow, and shiny, but under high temperature and high humidity conditions, its color will become darker over a long period of time, dark yellow or brownish yellow, known as "retting yellow valley", retting yellow The rice milled from the grain is also yellow, which is called "yellow to rice"
.
The reason for the production of retting yellow rice is the result of the growth and reproduction of microorganisms in the rice.
Due to the damage of molds, the nutrients of the rice are consumed in large quantities, the quality deteriorates, the taste deteriorates, and some are also affected by Aspergillus flavus, Aspergillus versicolor and green rice Mold pollution, the toxins produced by it will seriously affect human health
.
Especially if it is contaminated by Aspergillus flavus, the aflatoxin produced is very harmful to the human body.
Some people think that moldy rice can still be eaten after being boiled at high temperature.
This is wrong
.
Because general high-temperature cooking can't destroy the aflatoxin produced by mildew at all, therefore, must not eat rice that is already obviously moldy
.
　　11.
How to preserve flour in the family? 　　Flour is processed by wheat.
Because of its rich nutrition, strong moisture absorption, small particles, and poor thermal conductivity, it is very susceptible to insect pests, heat, mildew, and rancidity.
Therefore, flour is a kind at room temperature.
Food that is extremely difficult to keep
.
Consumers are advised to buy small-package products as much as possible, especially in summer, and eat them after opening the package, and do not store them for too long, which will affect the quality of eating
.
Uneaten flour should be placed in a cool, ventilated and dry place as much as possible
.
Do not store in light and humid environment
.
The storage temperature should not exceed 20 ℃ as much as possible
.
If you find that there are small dough balls in the flour that cannot be rubbed by hand, the color of the flour becomes darker, and a slightly sour taste appears, indicating that the flour has deteriorated and cannot be eaten
.
　　12.
When edible oil should be placed in a cool and dry place, it must be protected from light,　　heat and light, especially light in the ultraviolet and near ultraviolet range will significantly increase the oxygen absorption rate of edible oil and make it oxidatively rancid
.
Therefore, no matter what level of vegetable oil you buy home, be sure to place it in a cool and dry place and avoid direct sunlight
.
The easiest way is to make an oil bottle cover with thick cardboard (opaque) according to the size of the oil bottle, and click on it to solve the problem of avoiding light
.
　　13.
Do not place the oil bottle too close to the heat source　　The oxidation rate of edible fats and oils changes with the increase of temperature
.
When the temperature is higher than 60°C, the oxidation rate increases significantly
.
Therefore, after we have used up the oil bottle, we should stay away from high-temperature heat sources such as stoves and heating as much as possible
.
　　14.
Be careful when storing grease in high temperature summer.
The high temperature in summer　　is not conducive to the storage of grease
.
First, be careful not to buy excess oil in the summer, and try to buy small packages of oil
.
Second, linseed oil, safflower seed oil, sunflower seed oil and other highly unsaturated oils should not only be protected from light, but it is also best to store the opened ones in the refrigerator
.
Pay more attention to the storage conditions of the opened oil
.
　　15.
Tighten the bottle cap after use to reduce the contact time with air.
　　After you buy back the barreled cooking oil (whether it is 2.
5 liters or 5 liters), you can store it as described above before opening the bottle cap
.
Once the bottle cap is opened, it is best to divide it for use
.
It is recommended to use 500-600ml brown glass bottles (such as cooking wine bottles) to reduce light transmission and ventilation
.
Tighten the cap tightly after each use to reduce the contact time between the edible oil and the air
.
　　16.
Pay attention to the dryness and cleanliness of the bottle when dispensing.
When dispensing　　edible oil, the utensils used must be dry and clean
.
In addition to light and temperature, the reasons that cause oxidative rancidity of edible fats and oils can also promote the hydrolysis of fats and oils to produce free fatty acids; metal ions are strong pro-oxidants.
Therefore, the utensils used should not only be protected from light and oxygen, but also must be cleaned.
Let it dry before use
.
　　17.
Do not pour the used oil back into the bottle and mix it with new oil.
When　　frying food, you usually need to pour a lot of oil into the pan.
After frying, the remaining oil cannot be poured back into the bottle and mixed with the new oil.

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Although the used oil has not yet been oxidized to rancidity, in the frying process, it has been exposed to air at high temperature for a long time and has absorbed a large amount of oxygen.
Some unsaturated bonds have been epoxidized, and a small amount of oxygen free radicals have been Produced
.
The used oil is best stored in a bottle separately and used up as soon as possible.
The frying oil is best not to be used repeatedly
.
　　18.
Do not use an oil bottle to drain oil for a long time.
The oil bottle should be replaced　　with a small oil bottle for　　 dispensing
.
It is best not to use it repeatedly .
For convenience, many people pour in new oil after the oil in the oil bottle is used up for long-term repeated use
.
Do you know? The oil remaining in the lid and mouth of the oil bottle has been partially oxidized during repeated use
.
If you always use the same bottle, it will affect the quality of the newly poured oil, just like the sourdough used in making steamed buns, which greatly accelerates the oxidative rancidity of the new oil
.
　　19.
Why choose small packages for edible vegetable oil as much as possible? 　　You must choose the packaging quantity of edible vegetable oil according to your family's population and consumption.
The fresher the oil, the better, and the longer the storage time, the greater the risk of oxidative rancidity
.
If you have a large family, you can buy a 5-liter package.
Generally, a family of three should buy 2.
5 liters or smaller
.
Don't be afraid of trouble if you use it up again
.

　　Because the shelf life of the product is based on the premise that the mouth or barrel of the packaging container is tightly closed and does not leak and avoid light, when the package is opened, the shelf life will be shortened due to oxidation and deterioration due to exposure to air
.
Ordinary consumers cannot determine the quality of oil at home.
In order to ensure the safety when eating, they should try to choose small-package oil products
.
　　20.
Why is it said that cooking oil should not be stored for more than one year? 　　Edible oil is prone to acidification during storage, and its degree of acidification is related to the storage time.
The longer the storage time, the more serious the acidification, which will produce peroxides and other harmful substances to the human body, and gradually lose the unique fragrance of the edible oil.
Sour
.
If a person consumes edible oil that has been stored for too long, symptoms such as stomach upset, nausea, vomiting, abdominal pain, and diarrhea may occur
.
Therefore, cooking oil should not be stored for too long
.
　　So, how long should edible oil be stored for? The results of the investigation and research show that the edible oil stored within one year generally meets the national health standards and is harmless to the human body, while most of the edible oils stored for more than one year do not meet the national health standards
.
Therefore, the shelf life of edible oil is one year
.
　　21.
Oil that has passed its expiration date is not suitable for consumption.
　　Some families are accustomed to buying a lot of oil at one time.
Many families distribute oil during the holidays, send them to relatives and friends, etc.
, and accumulate oil that can’t be eaten for a long time
.
When it was eaten, it was found that the shelf life had passed
.
This kind of oil is best not to be consumed anymore, because the shelf life of refined oil is mainly maintained by the added antioxidants.
Once the shelf life expires, the antioxidants are exhausted, and the oxygen free radical reaction will proceed at an alarming rate
.
Maybe after opening the bottle cap, we haven't smelled the rancid smell, but the oxygen free radicals in it can't be smelled
.
　　22.
Can flocs appear in the edible oil stored in winter, is it still edible? 　　Oils and fats are fatty acid triglycerides
.
Due to the different carbon chain lengths of fatty acids that make up triglycerides, the temperature at which they crystallize is different.
The crystals need to be formed gradually, and they will take on several different forms, such as white flocs, opaque paste, white precipitation, and white crystals.
Wait, these are normal physical phenomena
.
Some consumers worry that the quality of frozen fat is not good.
In fact, this kind of worry is completely unnecessary
.
As the temperature changes, any edible oil will freeze to varying degrees, which is the physical property of the edible oil itself
.
The crystallization state is related to the conditions of transportation and storage of edible oil (for example, the temperature in the north is cold in winter, the edible oil loaded on the periphery of the truck is easier to freeze, and the edible oil placed in the north-facing kitchen is also easier to freeze) , Also related to the variety of fats
.
The freezing of edible oil will not affect its taste and quality at all
.
For ease of use, it is recommended that consumers should put edible vegetable oil in an environment of 20°C in winter
.