Food safety and energy assessment: From kitchen operating procedures to the precise measurement of food energy density
We cannot ignore bacterial infections caused by plant-based foods such as vegetables. Lettuce is safer if blanched in boiling water or stir-fried quickly over high heat. Pay attention to the rotting and spoilage of vegetables and fruits, and remove pesticide residues. Fruits such as apples, pears, and peaches are prone to mold and toxin production during storage. If small rotten spots are found, the entire fruit should be discarded. Fresh vegetables can produce nitrites when stored at high temperatures, which can have adverse effects on the human body. The ideal temperature for storing vegetables and fruits is around 0℃, but they should not be stored for extended periods.
Wash purchased vegetables thoroughly with clean water, then soak them in water for 10 minutes, followed by rinsing with clean water. This will remove most pesticide residues from the surface of the vegetables. Heating and cooking can destroy some heat-labile pesticides; for example, boiling spinach can destroy pesticide residues. Purchase food from reputable stores and supermarkets. Do not buy food from unlicensed street vendors, as they may evade supervision. Never let your guard down!
We need to understand the energy value and nutrient content of food. The human body's energy primarily comes from the oxidation of the three major nutrients in food: carbohydrates, fats, and proteins. In addition, people who drink alcohol also obtain some energy from it. To create a diet plan for weight control, we need to understand not only the energy value of various foods but also the content of the three major energy-providing nutrients: carbohydrates, fats, and proteins. The numerical value refers to the content per 100 grams of commercially available products. Energy value is expressed in kilocalories (kcal). 1 kcal = 4.184 kilojoules.
Generally, food composition tables list the nutrient content of the edible portion per 100 grams of food. However, for some foods, such as fish, shrimp, ribs, fruits, and nuts, a significant portion is inedible in commercially available products. Therefore, the nutrient content in the commercially available product differs from that in the edible portion. The content provided here is for reference only. Among grains and tubers, rice contains 346 kcal, millet contains 358 kcal, while rice porridge contains only 46 kcal. Fortified flour contains 350 kcal; however, due to different processing methods, steamed buns contain 208 kcal, while fried dough sticks contain a whopping 386 kcal.
Fresh corn, due to its high water content, contains only 49 kcal. Among beans and bean products, soybeans are extremely high in protein, reaching 35.1 grams, with 359 kcal. Tofu contains 98 kcal, while dried bean curd sticks, due to their concentrated nutrients, have a high energy content of 459 kcal. Among dairy and egg products, milk contains 54 kcal, while whole milk powder contains 478 kcal. Among livestock and poultry, lean pork contains 143 kcal, while fatty pork contains a high 395 kcal, and lean beef contains only 106 kcal. Fish and shrimp are generally low in energy; grass carp contains 65 kcal, and prawns contain 61 kcal. Vegetables are also very low in energy; Chinese cabbage contains 12 kcal, and broccoli contains 27 kcal.
The essential micronutrients for the human body refer to 20 vitamins, 7 macroelements, and 8 trace elements. According to surveys, the actual intake of several of these micronutrients differs significantly from the recommended intake. These include calcium, vitamin A, carotene, vitamin B1, vitamin B2, and zinc. While the average intake of vitamin C and iron meets the recommended levels, vitamin C is easily lost during storage and cooking. In my country, the iron intake of most residents comes from plant-based foods, which have a very low utilization rate in the body.
Therefore, these two nutrients are actually insufficient to meet the needs. We need to take them into consideration when designing diets for weight control to avoid deficiencies in these nutrients. Foods rich in Vitamin A include animal livers such as lamb liver, pork liver, and goose liver, as well as egg yolks. Foods rich in beta-carotene include dark green vegetables and fruits such as mangoes, broccoli, carrots, kale, and spinach. Foods rich in Vitamin B1 include black sesame seeds, pork, and lean pork. Foods rich in Vitamin B2 include pork liver, almonds, and seaweed. Foods rich in Vitamin C include fresh dates, kiwifruit, kale, and bell peppers. Foods rich in calcium include sesame paste, dried shrimp, dried shrimp, milk, and dried tofu.