Food Handling
Food Handling – Preservation and Storage
Food preservation
Core idea: Food preservation means treating or handling food so that it can be kept safe and fit for eating for a longer time without losing its nutritive value and taste.
| Aspect | Key Points | Exam Focus |
|---|---|---|
| Purpose | Prevent spoilage by stopping or slowing growth of bacteria, fungi and other microorganisms; reduce wastage; ensure availability in off-season. | “Why preserve food?” type conceptual questions. |
| Main causes of spoilage | Microbial growth, enzymes in food, insects, oxygen, moisture, improper temperature. | Matching cause with correct preservation method. |
| Principle | Change conditions (temperature, moisture, acidity, salt/sugar concentration) so that microbes cannot grow. | “Which method works by removing water / changing pH / lowering temperature?” |
| Method | How it is done | Example (Indian context) |
|---|---|---|
| Refrigeration and low temperature | Keeping food at low temperature (around 4°C in fridge, below 0°C in deep freezer) slows growth of microbes. | Milk, curd, vegetables, fruits, meat stored in household refrigerators. |
| Drying / dehydration | Removing moisture by sun-drying or using mechanical dryers; microbes cannot grow without water. | Sun-dried chillies, papad, dried fish, dried fruits, grain storage after complete drying in villages. |
| Salting and pickling | Adding salt, oil, spices and sometimes acid (vinegar); high salt or acid slows microbial growth. | Mango pickles, lemon pickles, fish pickles commonly prepared in Indian homes. |
| Sugaring | High concentration of sugar binds water and prevents microbial growth. | Jams, jellies, murabba (amla murabba, mango murabba). |
| Canning and bottling | Food filled in air-tight containers, heated to kill microbes and sealed to prevent re-entry. | Canned fruit juices, canned peas and tomato puree in supermarkets. |
| Chemical preservatives | Small, permitted amounts of chemicals like sodium benzoate and potassium metabisulphite added. | Soft drinks, squashes, ready-to-serve fruit drinks (as per FSSAI limits). |
| Pasteurisation | Milk heated to specific temperature for a short time and then quickly cooled; kills harmful microbes. | Pouched milk supplied by organised dairies. |
| Irradiation (higher level) | Exposing packed food to controlled ionising radiation to kill insects and microbes. | Spices, onion, potato in some commercial units. |
Memory Line: “Cold slows, heat kills, salt–sugar bind water, acid–oil block germs.” – connects main preservation principles.
Exam Tip: When the question highlights moisture removal, think of drying. When it highlights high salt / oil / spices, think of pickling. When it mentions short-time heating of milk, answer is always pasteurisation.
| Food | Main Spoilage Risk | Suitable Preservation Method |
|---|---|---|
| Milk | Rapid bacterial growth at room temperature | Boiling, pasteurisation, refrigeration, conversion to curd, paneer, ghee. |
| Cereals and pulses | Mould growth, insect attack | Proper drying, airtight storage, periodic sunning and fumigation. |
| Fruits and vegetables | Enzyme action, microbial growth | Refrigeration, pickling, making jams and juices, canning. |
| Fish and meat | Very quick putrefaction | Freezing, drying, salting, smoking, canning. |
Handling Tip: Even preserved food must be handled with clean hands, clean utensils and safe water. Preservation delays spoilage, but careless handling can still introduce new microbes.
Storage of food
Core idea: Safe storage of food means keeping raw and cooked food in such conditions that they remain nutritious, safe and free from contamination till they are used.
| Level | Key Practices | Typical Setting |
|---|---|---|
| Household level | Proper drying, use of tight containers, refrigeration, FIFO (first-in first-out). | Homes, hostels, small tiffin centres. |
| Community / school level | Clean godowns, safe water, rodent control, labelled bins. | Midday meal kitchens, anganwadis, hostel messes. |
| Commercial level | Cold storage, warehouses, controlled atmosphere stores. | Fruits, vegetables, milk products, grains in large scale. |
| Storage Problem | Cause | Preventive Storage Practice |
|---|---|---|
| Insects in wheat, rice, pulses | Improper drying before storage, open or torn bags, cracks in floor | Sun-drying before storage, jute or plastic bags on wooden planks, periodic sunning and using neem leaves in traditional practice. |
| Mould growth on grains and groundnuts | Stored with high moisture, damp godown | Store only after complete drying, maintain low humidity, regular inspection. |
| Spoilage of cooked food | Left at room temperature for long; repeated reheating | Cool and refrigerate within safe time, avoid keeping food in “danger zone” (roughly 5°C–60°C) for many hours. |
| Rodent and pest damage | Open access to store rooms | Rodent-proof doors, metal bins, regular cleaning and traps. |
Memory Line: “Dry well, cool right, close tight, use early.” – four checks for safe storage: moisture, temperature, container and duration.
| Item | Safe Home Storage Method | Extra Point for Exams |
|---|---|---|
| Cereals and pulses | Fully dried, stored in airtight containers or bags; kept on raised wooden platforms, away from walls. | Traditional Indian practice of mixing dried neem leaves helps repel insects (concept link to biopesticides). |
| Oils and ghee | Stored in dry, closed bottles or steel containers; away from direct sunlight. | Light and oxygen can cause rancidity (off flavour and smell). |
| Fruits and vegetables | Short-term: cool, airy place; longer: refrigerator or ventilated crates. | Poor storage leads to wilting, loss of vitamins and weight loss. |
| Milk and milk products | Refrigeration, quick consumption; some converted to curd, paneer, ghee. | High-risk category for microbial growth – often asked in food safety questions. |
| Ready-to-eat packed foods | Not opened: follow label instructions; After opening: use quickly, keep in fridge when required. | MCQs often test understanding of “expiry date”, “best before” and storage instructions on label. |
Exam Tip: In questions on storage, look for words like dry, cool, airtight, raised platform, FIFO, label. These are key hints for correct option related to safe storage and food safety.
Handling Tip: “First in, first out” means food stored earlier should be used earlier. This reduces chances of forgotten, expired or spoiled packets in home kitchens and stores.