How can the contamination of foods with microorganisms be prevented or minimized? How can the growth of microorganisms in foods be retarded? How can the microorganisms in foods be destroyed?

To prevent or minimize the contamination of foods with microorganisms, follow these steps: 1.1. Wash hands and surfaces thoroughly - Make sure to wash hands with soap and water for at least 20 seconds before and after handling food. Clean countertops, cutting boards, and utensils properly after each use. 1.2. Separate raw and cooked foods - Keep raw meats, poultry, and seafood separate from produce and cooked foods during storage and preparation to prevent cross-contamination. 1.3. Store food properly - Properly refrigerate perishable food items at 40°F (4°C) or below, freeze food at 0°F (-18°C) or below, and store dry goods in cool, dry areas to prevent bacterial growth. 1.4. Follow proper food handling practices - Do not use expired foods, always cook and reheat food to a safe temperature, and discard leftovers if they have been at room temperature for more than 2 hours.

To retard the growth of microorganisms in foods, employ these techniques: 2.1. Preservation methods - Use preservation techniques such as freezing, dehydration, canning, pickling, and using chemical preservatives to reduce the number of microorganisms in food. 2.2. Control moisture - Reduce the water activity of foods by dehydrating or drying them, as this limits the availability of water for microbial growth. 2.3. Maintain appropriate acidity levels - Acidic environments inhibit the growth of many microorganisms. Adding vinegar or lemon juice to foods can lower their pH, creating an unfavorable environment for microorganisms. 2.4. Use of antimicrobial agents - Some natural ingredients, such as salt and certain herbs and spices (e.g., garlic, turmeric), have antimicrobial properties and can help slow down the growth of microorganisms in foods.

To effectively destroy microorganisms in foods, consider these methods: 3.1. High-temperature cooking - Cooking food at high temperatures (e.g., boiling, frying, grilling, baking) can kill most bacteria, viruses, and parasites. The safe internal temperature varies for different types of foods, so it is important to use a food thermometer to ensure that food reaches the recommended safe temperature. 3.2. Pasteurization - Pasteurization is a heat treatment used to eliminate or reduce the number of harmful microorganisms in foods, especially liquids like milk and juices. It involves heating the food to a specific temperature for a certain period and then cooling it quickly. 3.3. Ultraviolet (UV) radiation - Ultraviolet germicidal irradiation (UVGI) is a technique used to deactivate microorganisms by exposing them to short-wavelength ultraviolet (UV) light. This method is used mainly to disinfect water, air, and surfaces in food processing facilities. 3.4. High-pressure processing (HPP) - Also known as cold pressure processing, HPP uses high levels of hydrostatic pressure to inactivate microorganisms in foods without the use of heat. This method can help maintain the sensory and nutritional qualities of food while ensuring food safety.