Grade 7 Chapter 5: Food Safety

Introduction to Food Safety

Food is essential for our survival, providing energy and nutrients. However, food can sometimes become unsafe to eat due to various reasons, leading to food spoilage or contamination. Food safety refers to the practices and conditions required to preserve food quality to prevent contamination and foodborne illnesses. Understanding food safety is crucial for our health and well-being.

Food Spoilage

Food spoilage refers to any undesirable change in food that makes it unfit for consumption. This can be due to:

• Microorganisms: Bacteria, fungi (moulds, yeasts) grow on food, breaking down its components and producing toxins.
• Enzymes: Natural enzymes present in food can cause ripening, browning, and degradation.
• Chemical reactions: Oxidation (e.g., rancidity in fats), non-enzymatic browning.
• Pests: Insects, rodents contaminating food.
• Physical damage: Bruising, cutting, which can accelerate spoilage.

Signs of spoilage include changes in color, smell, taste, texture, and the presence of visible mould or slime.

Food Preservation

Food preservation is the process of treating and handling food to stop or slow down spoilage, loss of quality, edibility, or nutritional value and thus allow for longer storage.

Methods of Food Preservation:

1. Drying: Removing water content from food to inhibit microbial growth.
   • Examples: Grains, pulses, dried fruits (raisins), dried fish.
2. Cooling/Refrigeration: Lowering temperature to slow down microbial growth and enzymatic activity.
   • Examples: Fruits, vegetables, milk, cooked food.
3. Freezing: Lowering temperature below 0°C to stop microbial growth and enzymatic activity.
   • Examples: Meat, fish, vegetables, prepared meals.
4. Boiling: Heating food to high temperatures to kill microorganisms.
   • Examples: Milk, water.
5. Smoking: Exposing food to smoke from burning wood, which adds flavor and has preservative properties.
   • Examples: Fish, meat.
6. Use of Preservatives: Adding chemical substances to food to inhibit microbial growth.
   • Natural Preservatives: Sugar (jams, jellies), salt (pickles, salted fish), oil (pickles).
   • Chemical Preservatives: Sodium benzoate, potassium metabisulphite (used in sauces, squashes).
7. Pasteurization: Heating liquid food (like milk) to a specific temperature for a set period, then rapidly cooling it, to kill harmful bacteria without significantly altering taste.
   • Invented by: Louis Pasteur.
8. Canning: Sealing food in airtight containers after heating to destroy microorganisms.
   • Examples: Canned fruits, vegetables, meat.
9. Use of Inert Gas: Flushing food packages with inert gases (like nitrogen) to prevent oxidation and microbial growth.
   • Examples: Packaged snacks (chips).

Food Adulteration

Food adulteration is the act of intentionally debasing the quality of food by mixing or substituting inferior or harmful substances, or by removing valuable ingredients. It is a serious public health concern.

Common Adulterants and their Effects:

• Water: Added to milk to increase volume (reduces nutritional value).
• Stones, pebbles, sand: Mixed with grains, pulses (causes digestive issues, dental problems).
• Brick powder: Mixed with chili powder (causes digestive problems).
• Metanil yellow: A non-permitted dye added to turmeric powder or sweets (carcinogenic, affects nervous system).
• Chalk powder: Mixed with flour or sugar (causes digestive issues).
• Used engine oil: Mixed with edible oil (highly toxic, causes severe health problems).
• Papaya seeds: Mixed with black pepper (reduces flavor, causes digestive issues).
• Artificial colors: Used in sweets, often harmful.

How to detect adulteration:

• Simple tests can be performed at home (e.g., water test for milk, magnet test for iron filings).
• Look for certified labels (e.g., FSSAI in India).

Importance of Food Safety and Avoiding Adulteration:

• Health Protection: Prevents foodborne illnesses, poisoning, and long-term health issues.
• Nutritional Value: Ensures food retains its original nutritional content.
• Economic Impact: Reduces wastage, ensures fair trade.
• Consumer Trust: Builds confidence in food products.

Summary

• Food Spoilage: Undesirable changes in food making it unfit for consumption, caused by microbes, enzymes, etc.
• Food Preservation: Methods to prevent spoilage and extend shelf life (drying, cooling, freezing, boiling, smoking, preservatives, pasteurization, canning, inert gas).
• Food Adulteration: Intentionally debasing food quality by adding inferior/harmful substances or removing valuable ones.
• Common Adulterants: Water in milk, stones in grains, brick powder in chili powder, metanil yellow in turmeric, chalk powder in flour, used engine oil in edible oil, papaya seeds in black pepper.
• Importance: Ensures health, maintains nutritional value, prevents economic loss, builds consumer trust.