First of all, the human body's demand for nutrition
Life activities need to consume "energy", just as engines need gasoline and electric lights need electricity. The source of this energy is the food that people eat every day. Protein, fat and sugar in food can be transformed in the body to provide energy for human activities. Lipids, fats and sugars in protein are called "heat source substances". In addition to "heat source substances", vitamins, inorganic salts and water in food are also essential nutrients for human body. Although it cannot provide heat, it is indispensable for human metabolism, growth and development. Therefore, the nutrients needed by human body are protein, fat, sugar, inorganic salts, vitamins and water, which are usually called the six major nutrients.
1, protein: It is the foundation of life and the most basic substance that constitutes the human body. There is no place in human muscle, bone, blood and hair that does not contain protein. Without protein, there would be no life. Protein consists of more than 20 kinds of amino acids, eight of which can't be synthesized or under-synthesized in human body, and must be supplied by food, which is called "essential amino acids". Protein is divided into animal protein and plant protein.
The total amount of protein a person needs every day depends on age, sex, working conditions and health status. Children and adolescents need more protein during their growth and development, and so do women during pregnancy and breastfeeding.
2. Fat: It is a nutrient rich in calories, including fatty acids and lipids, and is one of the important components of the human body. Fat mainly comes from animal and vegetable oils. Too much fat is harmful to human health, especially don't eat too much animal fat.
3. Sugar: Sugar, also known as carbohydrate, can be divided into monosaccharide (fructose and glucose), disaccharide (sucrose, maltose and lactose) and polysaccharide (starch, glycogen, cellulose and pectin, etc.). ), and sugar is one of the important nutrients.
4. Inorganic salts: Inorganic salts are also called minerals. There are many inorganic salts in human body, such as calcium, magnesium, potassium, sodium, phosphorus, oxygen, sulfur and some trace elements.
① Calcium: It is the most abundant inorganic salt in human body and one of the most easily lacking elements in human body. Calcium is the main component of bones and teeth. Calcium comes from milk and dairy products. Beans, cereals, vegetables, shrimp skin, fish and shrimp are also important sources of calcium. Children need 1000 mg of calcium every day to meet the needs of growth and development.
② Iron: It is a trace element with little content in human body. Because of its important functions such as oxygen transport and exchange, it is an essential nutrient for human body. If food is deficient in iron for a long time, iron deficiency anemia will occur. The absorption and utilization of iron are influenced by many factors. Iron in animal food is easy to absorb, while iron in plant food is not easy to absorb. In China, food ingredients are mainly plant foods, so it is easy to cause iron deficiency. Foods containing more iron include egg yolk, liver, kidney, grains, beans and green leaves. Children and adolescents need iron 15g every day.
③ Iodine: Iodine is also an essential trace element for human body. Iodine deficiency can cause goiter, commonly known as "big thick neck", and also affect the energy metabolism of human body and the growth and development of children. The general iodine requirement is 100- 140 micrograms per person per day, and iodization with salt may solve the problem of iodine deficiency.
Vitamins are indispensable substances to maintain human health. There are many kinds of vitamins, which can be roughly divided into two categories. One is fat-soluble vitamins, which are soluble in fat, such as vitamin A, vitamin D and vitamin K, and the other is water-soluble vitamins, namely vitamin B (including vitamin B 1, B2, B6, B 12, cupric acid, folic acid, pantothenic acid, etc. ) and vitamin C.
Diseases caused by vitamin deficiency:
Vitamin A deficiency: night blindness, dry eye and keratomalacia, dry skin and keratosis of hair follicles.
Vitamin D deficiency: rickets in children and osteomalacia in adults.
Lack of vitamin B 1: beriberi
Vitamin B2 deficiency: diseases of mouth, skin and legs.
Vitamin c deficiency: scurvy
Second, food pollution.
Food refers to all kinds of finished products and raw materials for human consumption or drinking, as well as articles that are traditionally both food and medicine, but do not include articles for therapeutic purposes.
What is food pollution?
Food (food) from crop growth to harvesting and picking, from production, processing, transportation, storage, sales to eating, due to various conditions and factors, the original non-toxic and harmless food is mixed with some toxic and harmful substances, which reduces the nutritional value and sanitary quality of food. People who eat this kind of food will bring different degrees of harm to human health. This process is called food pollution.
(1) Classification of food pollution:
1. Biological pollution: microbial parasites, eggs and insects will cause biological pollution, and microorganisms mainly include bacteria and their mycotoxins, molds and mycotoxins.
If these appear in food, it will lead to food poisoning and zoonotic infectious diseases. Food pollution caused by parasites and eggs often leads to roundworms, tapeworms and Trichinella spiralis.
2. Chemical pollution: including food pollution caused by harmful metals, nonmetals, organic compounds and inorganic compounds, such as mercury, arsenic, lead, cadmium, nitrite, organophosphorus and organochlorine.
3. Radioactive pollution: mainly comes from the mining and smelting of radioactive substances, as well as the application and discharge in national defense, production and life.
(B) the harm of food pollution to the human body
The main sources of food pollution are the pollution of raw materials, the pollution in the process of production, storage, transportation, sales, processing and cooking, and the pollution caused by employees' failure to seriously abide by the operating rules.
After food is polluted, some of them lead to a large number of bacteria and reproduction or endotoxin and exotoxin in food, and eating such food will lead to intestinal infectious diseases and food poisoning; Some foods are contaminated by bacteria, which will lead to food spoilage after a certain period of time. People who eat this kind of food will not only lose a lot of nutrition, but also cause food poisoning, and they can also suffer from dysentery, diarrhea, cholera, paratyphoid fever, paratyphoid fever and so on.
Third, food poisoning.
Food poisoning is an acute disease caused by people eating poisonous food.
The reasons for the formation of toxic food are as follows:
1, food is contaminated by pathogenic microorganisms (bacteria, molds, etc.). ) and a large number of proliferation, so that there are a large number of live bacteria and toxins in food.
2. Food is contaminated by chemical poisons, reaching the toxic dose.
3. Intake some animals and plants containing natural toxic ingredients.
4. Intake of toxins transferred by animals and plants twice.
(1) bacterial food poisoning
Bacterial food poisoning mainly occurs in summer and autumn when the temperature is high, because the temperature in this period is suitable for the reproduction and toxin production of pathogenic bacteria, which leads to food poisoning caused by pathogenic bacteria. Clinical manifestations of bacterial food poisoning;
Animal food poisoning is characterized by fever, headache, dizziness, loss of appetite, followed by nausea, vomiting and diarrhea, 7-8 times a day, with a fever of 38-40℃. In severe cases, blood pressure drops, convulsions and coma, and in severe cases, people may die of heart failure and renal failure.
Prevention: When processing meat products, raw and cooked meat pieces must be separated, and the meat pieces should be preserved at low temperature or pickled in cook the meat. The thickness should not exceed 2kg, 8cm, boiled for more than 3 hours, and boiled with eggs for more than 10 minutes. The food left over from the previous meal must be returned to the pot for heating before eating.
(2) Fungal food poisoning
Mildew sugarcane poisoning
During the overwintering storage of sugarcane after harvest, due to unsanitary environment and fungal pollution, fungi will multiply in sugarcane and produce toxins, and food poisoning will occur when sugarcane with toxins is eaten. Sugarcane poisoning mostly occurs in spring.
Clinical manifestations of sugarcane poisoning: nausea, vomiting and diarrhea appear soon. Some stools are black, some have headache, dizziness and diplopia. In severe cases, convulsions may occur, eyes staring upward at the same time, pupils dilated and teeth clenched. Those who are light recover quickly, and those who are heavy have a high mortality rate.
Precautions: ① Harvest the sugarcane when it is ripe; ② The storage time after harvest should not be too long; 3 moldy sugarcane must not be eaten and should be destroyed in time.
(3) Food poisoning of poisonous animals and plants
① Bean poisoning
Generally, beans will not be poisoned, but eating undercooked beans will be poisoned, which may be related to the fact that beans contain hemagglutinin and are not destroyed by heating.
The incubation period of bean poisoning is short, and it occurs as soon as 10 minute after eating. The main symptoms are nausea, vomiting, diarrhea, headache, dizziness, chest tightness, cold sweat and numbness of limbs.
Precautions: Kidney beans should be stewed and processed for a long time, which will destroy the poison. You must not stir-fry in a hurry, and it is not suitable for cold salad.
② Poisoning of germinated potato.
③ Poisoning by poisonous mushrooms
(4) Chemical food poisoning
1, sulfite poisoning
(1) vegetables are not fresh, and nitrite poisoning may occur when they rot and deteriorate.
(2) Nitrite will also be produced during the curing process of vegetables.
(3) Excessive chromogenic agent is used to make cooked food, and excessive nitrite causes poisoning.
④ Bitter well water can also cause nitrite poisoning.
Poisoning symptoms: cyanosis of lips, cyanosis of conjunctiva, eye stones and nails, dizziness, headache and nausea. In severe cases, dyspnea, blood pressure drop and even respiratory paralysis lead to death.
Prevention: ① Do not eat rotten vegetables; ② Don't drink bitter well water; ③ It is best to observe the curing condition when curing vegetables; If the salt concentration reaches more than 65,438+05%, we should eat the nitrates and nitrites of processed meat products that have been marinated for half a day to 65,438+0 days. (4) nitrate and nitrite should be used according to the prescribed dosage, and shall not be added at will. ⑤ Strictly manage antifreeze (potassium nitrite, etc.). ) for the construction department (site) to prevent food poisoning caused by drinking water and food pollution.
2, organophosphorus pesticide poisoning
Commonly used organophosphorus pesticides are trichlorfon, dichlorvos, 1605, 1059, etc. It is very toxic to people and livestock.
Poisoning symptoms: rapid onset, fatigue, pupil contraction, partial salivation, sweating, nausea, vomiting, muscle tremor, dyspnea, coma, pulmonary edema, incontinence and even death in severe cases.
Prevention: publicize the correct use methods and precautions of pesticides, strengthen the management of pesticides, prohibit the mixed storage of pesticides and food, and prohibit the use of containers and packages containing pesticides to hold and package food.
Four, students in the food safety work matters needing attention
1. When eating out: Be sure to eat in a collective canteen with hygiene license or a restaurant with complete disinfection facilities, and never buy amorphous packaged food from street vendors.
2. When buying snacks and drinks: Be sure to see if the packaging is clean and complete. Whether there is a manufacturer, production date and shelf life. All "three noes" and expired foods and drinks must not be eaten.
3. Develop good hygiene habits, wash your hands before and after meals, cut your nails frequently, get a haircut frequently, change clothes frequently and take a bath frequently. No littering, no spitting. I haven't found any articles about feedback yet, but I hope this will help you. It's material! There's always something to write, isn't there?