Summary of "LA CONSERVACIÓN DE LOS ALIMENTOS"

LA CONSERVACIÓN DE LOS ALIMENTOS

Presenter: Biologist Danny Altamirano, Food Safety Specialist, General Directorate of Environmental Health, Ministry of Health (Peru)

Ingredients & Quantities

No specific cooking ingredients or quantities are provided, as this is an educational presentation on food preservation methods rather than a cooking recipe.

Food Preservation Methods Covered

1. Classification of Foods by Perishability

Perishable: Milk, fresh cheese, eggs, meats (especially minced or filleted), sauces with egg or milk, some cakes. These spoil easily and require careful preservation.
Semi-perishable: Potatoes, nuts, canned foods. Longer shelf life due to processing.
Non-perishable: Flour, sugar, pasta, sugar-heavy products. Long shelf life without special preservation.

2. Factors Causing Food Deterioration

Biological (microorganisms, enzymes)
Physical (bruising, crushing, dehydration)
Chemical (oxidation, vitamin loss, rancidity)
Contamination by insects, rodents, or foreign substances
Radiation (visible, infrared, invisible rays damaging nutrients and appearance)

3. Methods to Delay Food Spoilage

Lower temperature and humidity
Proper packaging
Avoiding sunlight exposure
Proper cooking (boiling)
Adding preservatives or chemical substances
Pasteurization and sterilization
Maintaining cold chain during transport

Specific Preservation Techniques

A. Cold Preservation

Refrigeration: Slows chemical reactions and microbial growth. Use correct fridge zones (vegetables, meats, freezing area). Avoid overfilling to maintain airflow.
Freezing: Below 0°C, water in food turns to ice, halting microbial activity. Freeze quickly at very low temperatures to preserve quality.

B. Heat Preservation

Blanching (Scalding): Vegetables are cleaned, immersed in boiling water briefly, then vacuum-packed and frozen. This deactivates enzymes and extends freezer life (up to 6 months).
Pasteurization: Industrial heat treatment (~80°C for short time) kills disease-causing germs but not spores; minimal nutrient loss. Used in milk, juices.
Sterilization: Higher heat (~115°C) kills spores but affects flavor, nutrients, and texture.

C. Chemical Methods

Salting: Dehydrates food by drawing out water; common in dried meats.
Smoking: Uses smoke from burning specific woods to flavor and preserve meats; inhibits microbes.
Acidification (Pickling): Uses vinegar and salt to lower pH, preventing microbial growth and adding flavor.
Sugar Addition: High sugar concentration in jams/jellies protects against microbes.

D. Dehydration

Removes water to reduce microbial growth. Includes traditional drying and freeze-drying (removes water from frozen food by vacuum sublimation).
Also mentions irradiation to extend shelf life by preventing germination and spoilage, though it may reduce some vitamins.

E. Vacuum Packaging

Removes air to inhibit aerobic microorganisms, extending shelf life.

Equipment & Preparation Tips

Use appropriate fridge zones for different foods.
Avoid overcrowding refrigerators to allow cold air circulation.
Use transparent, food-grade freezer bags (avoid colored or painted bags to prevent chemical migration and equipment damage).
For freezing meats, portion into daily-use sizes before freezing to avoid repeated thawing/refreezing.
Glass containers preferred over plastic Tupperware unless certified food-safe; glass preserves nutrients better and saves space.

Preservation Tips for Specific Foods

Breast Milk: Refrigerate for 3-4 days; freeze if longer storage needed.
Scalded (Blanched) Foods: Freeze for up to 6 months; refrigerate and consume quickly otherwise (max ~6 days).
Cheese: Wrap in kraft paper and place inside a container (e.g., Tupperware) to avoid moisture buildup and mold; refrigerate. Avoid plastic bags alone.
Eggs: Refrigerate especially in warm climates; consume within 3-4 days. Wash before use to avoid contamination.
Disaster/Emergency Food: Prefer non-perishable canned foods with verified shelf life. Avoid perishable items like eggs due to risk of spoilage and contamination.

Common Mistakes to Avoid

Refreezing thawed meat after cutting.
Using non-food grade or colored plastic bags for freezing.
Overfilling refrigerators, blocking airflow.
Storing cheese in plastic bags only, which promotes mold.
Taking perishable foods without proper cold chain in emergency situations.

Additional Notes

Refrigeration preserves nutrients best when used for short-term storage.
Longer preservation times generally reduce nutritional and sensory quality.
For transporting food, use coolers with gel refrigerants to maintain temperature.

Plating/Serving Suggestions

Not applicable; focus is on preservation rather than cooking or plating.

Summary

This video provides a comprehensive overview of food preservation principles and methods, focusing on maintaining food safety, extending shelf life, and preserving nutritional and sensory qualities. It covers the classification of foods by perishability, factors causing spoilage, and multiple preservation techniques including refrigeration, freezing, blanching, pasteurization, sterilization, chemical preservation, dehydration, irradiation, and vacuum packaging. Practical advice on packaging, storage, and transport is given, along with answers to common questions about specific foods like breast milk, cheese, and eggs. The importance of maintaining the cold chain and using appropriate materials for storage is emphasized to avoid contamination and quality loss.

Source: Tele-Training session by Biologist Danny Altamirano, Ministry of Health (Peru), available on the Tele Salud Mitad YouTube channel.