Food Preservation: Methods, Additives, and Safe Handling
Fresh Foods
Fresh foods are those that have not undergone any preservation process, additional treatment, or transformation that extends their shelf life. They should be stored in places with low humidity and away from products that transmit odors.
Types of Fresh Foods
In fresh food stands, you can find perishable and non-perishable foods:
Perishable Foods
These foods are offered for immediate consumption because their preservation is very limited.
Non-Perishable Foods
These foods have a dry consistency, such as legumes, rice, pasta, sugar, and cookies. They last much longer than perishable foods.
Food Processing
Food processing encompasses all the activities that occur from the moment raw materials are received until the final product is ready. For example, meat processing includes slaughtering at the slaughterhouse, cutting, and preparing parts for sale (chopped meat, sausages, burgers, or other fresh derivatives).
Food Preservation
The goal of food preservation is to control the various reactions that occur in foods due to physical (heat, light, moisture), chemical (oxidation), or biological (enzymes, microorganisms, fungi, bacteria) factors. Preservation involves maintaining the nutritional qualities of food for an extended period.
Physical Methods of Preservation
Freezing, sterilization, and vacuum packaging are physical methods used to lengthen the life of food while maintaining its nutritional and organoleptic characteristics (color, taste, smell, and texture).
Chemical and Biological Methods of Conservation
Fermentation, smoking, pickling, salting, and adding sugar are techniques that alter some nutritional and organoleptic properties of food. These techniques are used to extend the preservation of food.
Thermal Processing
Physical methods of preservation often involve heat treatments. The primary goal of all thermal treatments is to destroy living microorganisms that can degrade food quality or harm consumers’ health.
Steaming
Steaming does not significantly destroy microorganisms. It is accomplished using steam or hot water at a temperature of 85-95°C for 5 minutes and is typically applied to fruits and vegetables.
Pasteurization
Pasteurization is mainly used for liquids like fruit juices and milk. It involves heating the liquid to a temperature below 100°C, between 65 and 75°C, for 20 to 30 minutes. The liquid is then rapidly cooled to 4°C. Pasteurization destroys pathogenic bacteria, and pasteurized products must be stored refrigerated.
Sterilization
Sterilization involves heating food to a temperature of 115 to 120°C for about 10 minutes. Due to the high temperature, sterilized foods undergo more changes than pasteurized foods. The goal is to destroy all microorganisms, including pathogens, that may affect the food’s quality. Sterilized foods do not require refrigeration and can last for about 6 months.
UHT (Ultra-High Temperature)
UHT processing involves applying high temperatures (around 140°C) for a short time (1-2 seconds). This method maximizes nutrient retention and minimizes changes in the product’s smell and taste.
Refrigeration
Refrigeration keeps food at temperatures between 0 and 4°C, slowing down enzymatic processes and the proliferation of certain microorganisms.
Freezing
Freezing involves applying low temperatures to freeze food completely. The process must be rapid to avoid the formation of ice crystals in the food. The storage temperature for frozen food is -18°C.
Food Additives
Food additives are authorized substances added in small amounts to foods and beverages without significantly changing their nutritional value. They are used to modify characteristics, processing, and preservation techniques.
Antioxidants
Antioxidants prevent the oxidation of fats caused by heat, light, and metals. They help maintain the product’s original color, smell, taste, and texture.
Preservatives
Preservatives prevent the product from being affected by bacteria, yeasts, and fungi, which can cause significant losses of finished products.
Additives that Modify Color, Smell, and Taste
These additives are used to make food more appealing to consumers.
Dyes
Dyes add or restore color to food (e.g., caramel, cochineal, saffron, paprika).
Sweeteners
Sweeteners are substances other than sugar that impart a sweet taste to food. They can be natural (e.g., fructose, mannitol, glycerol) or artificial (e.g., cyclamate, saccharin, aspartame).
Flavoring
Flavoring agents provide olfactory properties (e.g., E 330 in soft drinks, soups, sauces).
Flavor Enhancers
Flavor enhancers enhance the taste or odor of food. They are often used in foods that have been dehydrated or frozen and have lost some of their original flavor, such as broths, soups, ready meals, and canned vegetables.
Food Storage and Transport
Storage
Food storage is essential at various stages in the food industry. General aspects of proper storage include:
- Maintaining appropriate temperature and humidity for the specific food being stored.
- Ensuring adequate air circulation.
- Separating foods that emit strong odors from those that can absorb them.
Shopping Cart
Minimum requirements for safe food handling during shopping and consumption:
- Check packaging dates: The expiration date indicates the limited preservation time beyond which the food may cause health problems. The best-before date is used for long-life products and indicates that the product’s quality may decline after this date.
- Read the nutrition information: Many labels provide information on the major nutrients, energy content, and quantities present in the product. This information can be helpful for planning menus.
- Verify that the packaging is in perfect condition.
- Buy only the fresh foods you need, as their shelf life is limited.
- Minimize the time frozen and refrigerated foods spend at room temperature.
Refrigeration
The refrigerator temperature should be between 0 and 5°C. Foods should be spaced to allow air circulation. Organize them according to their recommended storage temperatures: vegetables in the least cold area, meat and fish above them, followed by cooked foods, sausages, and dairy products in the coldest section.
- Meat: 2 to 3 days, except for ground meat, which should be consumed within one day.
- Fish: 1 day if fresh, 2 to 3 days if cooked.
- Milk: 2 to 3 days for pasteurized milk, 3 to 4 days for sterile milk in unopened packaging.
- Vegetables: 4 to 5 days raw, 3 to 4 days cooked.
- Opened preserves: 4 to 5 days.
Protect foods from direct sunlight unless they are specifically designed to withstand it.
Transportation
During transportation, it is crucial to maintain optimal preservation conditions for food, including temperature and humidity control. Avoid mixing foods that could negatively interact with each other.