Punjab PSEB Matric NSQF Food Processing cheat sheet

Food processing is any deliberate operation that transforms raw agricultural material into a stable, safe, palatable food; food science is the study of the chemistry, microbiology, physics and engineering behind those operations.

Water activity (aw) equals the vapour pressure of water in the food divided by that of pure water at the same temperature; pure water is 1.00 and most spoilage bacteria stop growing below about 0.90.

Perishable foods (milk, meat, fish) spoil within days without treatment; semi-perishable foods (potatoes, apples, nuts) last weeks to months; shelf-stable foods (flour, sugar, canned goods) last months to years at ambient temperature.

Proximate analysis partitions a food into moisture, crude protein (Kjeldahl N x 6.25), crude fat, crude fibre, ash and nitrogen-free extract (carbohydrate by difference).

The three spoilage routes are microbial growth, chemical or enzymatic reaction (browning, rancidity, vitamin loss) and physical damage (moisture migration, bruising, light); each preservation method targets one or more of these.

Primary processing converts the harvest into a basic commodity (milling, pasteurising, filleting); secondary processing turns commodities into consumer products (baking, canning, extrusion).

A calorie (kcal) is the energy needed to raise 1 kg of water by 1 degree Celsius; carbohydrate and protein supply about 4 kcal/g, fat about 9 kcal/g, alcohol about 7 kcal/g.

Unit operations such as heating, cooling, drying, size reduction, mixing and separation are combined in a process flow diagram to make a complete process.

Hazard categories are biological (bacteria, viruses, parasites, moulds), chemical (pesticide residues, cleaning agents, mycotoxins, allergens) and physical (glass, metal, stones, hair).

The five keys to safer food are: keep clean; separate raw and cooked; cook thoroughly; keep food at safe temperatures; use safe water and raw materials.

Danger zone for microbial growth is roughly 5 to 60 degrees Celsius; keep hot food above 60 C and cold food at or below 5 C, and limit time in the zone to under 2 hours.

Personal hygiene rules: wash hands with soap before handling food and after toilet or waste contact; no bare-hand contact with ready-to-eat food; clean outer clothing; no jewellery; exclude staff with vomiting, diarrhoea or infected skin lesions.

Cleaning removes soil with detergent and mechanical action; sanitising then reduces microorganisms with heat or an approved chemical such as chlorine solution or hot water above 77 C for the contact time specified.

Cross-contamination is controlled by colour-coded chopping boards and utensils, separate raw and cooked storage, and washing and sanitising surfaces between uses.

Pest control relies on proofing (screens, door sweeps, sealed cracks), removing food and water sources, correct waste handling, and documented monitoring rather than spraying pesticides near food.

HACCP has seven principles: hazard analysis, determine critical control points, set critical limits, monitor, establish corrective actions, verify, and keep records.

Preservation works by one or more of: removing or killing microorganisms (heat, filtration, irradiation), lowering water activity (drying, salting, sugaring), lowering pH (fermentation, acidification), lowering temperature, excluding oxygen or adding preservatives.

Pasteurisation heats to below 100 C (typically 63 C for 30 min or 72 C for 15 s for milk) to kill vegetative pathogens; sterilisation destroys all microorganisms and their spores, as in commercial canning.

Refrigeration slows growth to roughly 0-5 C; freezing at -18 C or below stops growth but does not kill microorganisms, so thawed food spoils as fast as fresh.

Drying reduces water activity below about 0.60, the level at which no microorganism can grow; sun drying, hot-air drying, freeze drying and osmotic drying all achieve this.

Salting and sugaring preserve by osmosis, binding free water and raising osmotic pressure so cells cannot grow; a 15-20 percent salt brine or a high-sugar jam is typical.

Acidification to pH below 4.6 prevents growth of Clostridium botulinum; acid foods such as pickles and fruit products are therefore safe to process at lower heat than low-acid foods.

Chemical preservatives permitted in India under FSS Regulations include benzoic acid and its salts, sulphur dioxide and sulphites, and nitrites for cured meats, each with maximum limits by product category.

Canning is a combined process: blanching, filling, exhausting, hermetic sealing and heat treatment measured as F-value, which is the time at a reference temperature needed to achieve the required lethality.

Size reduction equipment: jaw and roll crushers for coarse work, hammer mills and ball mills for fine grinding, and slicers, dicers and pulpers for fruits and vegetables.

Heat exchangers: plate exchangers give high heat transfer for liquids such as milk; shell-and-tube units suit higher pressures; scraped-surface exchangers handle viscous or particulate products.

Evaporators concentrate liquids by boiling off water; a multiple-effect evaporator reuses vapour from one effect to boil the next, cutting steam demand roughly in proportion to the number of effects.

Drying equipment includes tray and cabinet dryers (small batch), tunnel dryers (continuous), drum dryers (purees, flakes), spray dryers (milk powder, instant coffee) and fluidised-bed dryers (granules, peas).

Separation equipment: screens and sieves classify by particle size; centrifuges and cyclones separate by density; filters remove solids from liquids; membrane units (ultrafiltration, reverse osmosis) separate by molecular size.

Mixing equipment ranges from paddle and ribbon blenders for solids to propeller and turbine agitators for liquids; homogenisers force product through a narrow valve at high pressure to reduce fat globule size.

Material balance: mass in equals mass out plus accumulation; component balance on one constituent (for example solids) lets you compute the composition of a blend or the yield of a process.

Overall equipment effectiveness (OEE) equals availability x performance x quality, where each factor is a ratio of actual to ideal values.

Fruits and vegetables are graded, washed, blanched, then processed by canning, freezing, drying, juicing, pulping or pickling; blanching inactivates enzymes (peroxidase, polyphenol oxidase) that cause browning and off-flavours.

Enzymatic browning is catalysed by polyphenol oxidase on cut surfaces; it is controlled by blanching, ascorbic acid or citric acid dips, sulphiting, or excluding oxygen.

Wheat milling separates bran, germ and endosperm; the endosperm is reduced to flour, and extraction rate is the mass of flour obtained as a percentage of the clean wheat.

Wheat flour quality depends on gluten proteins, gliadin and glutenin, which form an elastic network on hydration and kneading; hard wheat gives strong gluten for bread, soft wheat suits biscuits and cakes.

Rice milling removes husk (husker or sheller) then bran and germ (polisher); parboiling soaks, steams and dries paddy before milling, gelatinising starch and pushing vitamins into the grain.

Pulses and oilseeds are cleaned, de-hulled, and for oilseeds pressed or solvent-extracted; oil is then refined by degumming, neutralising, bleaching and deodorising.

Jam, jelly and marmalade rely on pectin, sugar and acid forming a gel; a good set needs roughly 65 percent soluble solids and pH around 3.0 to 3.5.

Fruit juice processing includes extraction, clarification or pulping, deaeration, pasteurisation and filling; enzymatic treatment with pectinase improves yield and clarity.

Milk composition (cow) is roughly 87 percent water, 3.4 percent fat, 3.3 percent protein, 4.8 percent lactose and 0.7 percent minerals; solids-not-fat is total solids minus fat.

Milk treatment sequence: reception and testing, filtration or clarification, standardisation of fat, homogenisation, pasteurisation, then cooling or further processing into products.

Products from milk include cream, butter, ghee, curd and yoghurt, cheese, paneer, condensed and evaporated milk, milk powder and ice cream; each relies on concentrating or fermenting milk solids.

Meat is converted to edible condition by post-mortem glycolysis and rigor mortis; chilling slows these changes, and conditioning or ageing improves tenderness by enzymatic proteolysis.

Meat curing uses salt, nitrite, sugar and sometimes smoke; nitrite gives the pink colour and suppresses Clostridium botulinum, and residual nitrite is limited by regulation.

Poultry processing steps are stunning, bleeding, scalding, plucking, evisceration, chilling (often in ice water), grading and packing; scalding temperature differs for soft and hard scald.

Fish spoils fast because of high water activity, neutral pH and enzymes; preservation uses icing, freezing, salting, drying, smoking and canning, and freshness is judged by rigor, eyes, gills and odour.

Cold chain for perishables means holding product continuously within a specified temperature range from processing to retail, verified by data loggers and temperature records.

Packaging functions are containment, protection from physical, chemical and biological hazards, convenience and communication (label, brand, instructions).

Materials: glass is inert and impermeable but heavy and fragile; tinplate and aluminium cans are strong and heat-processable; paper and board are cheap and printable but poor moisture barriers; plastics vary widely in oxygen and moisture permeability.

Flexible laminates combine layers, for example metallised polyester for barrier, aluminium foil for light and oxygen, and polyethylene for sealing, to give properties no single film provides.

Modified atmosphere packaging replaces air with a gas mix, typically low oxygen and elevated carbon dioxide, to slow respiration of fresh produce and growth of aerobic spoilage organisms.

Aseptic packaging fills commercially sterile product into pre-sterilised packaging in a sterile zone, giving ambient shelf life without refrigeration.

Storage conditions to control are temperature, relative humidity, light and ventilation; dry stores should be cool, dry and pest-proof, and bags should be palletised off the floor.

Transport requirements include clean, dry vehicles, temperature-controlled or insulated bodies for perishables, correct stacking to avoid crushing, and traceability of each consignment.

Shelf life is the period a product retains acceptable safety, sensory and nutritional quality under stated storage conditions; it is set by storage trials and accelerated testing.

Quality attributes cover sensory (appearance, texture, flavour), chemical (composition, additives), microbiological (counts, pathogens) and physical (moisture, texture, colour) measures.

Food Safety and Standards Authority of India (FSSAI) administers the Food Safety and Standards Act 2006; a 14-digit licence or registration number identifies the food business.

FSSAI licence categories: basic registration for turnover up to 12 lakh rupees, state licence above that up to 20 crore rupees, and central licence above 20 crore rupees or for importers and certain categories.

Mandatory label elements in India include name of food, list of ingredients in descending order of weight, nutritional information, vegetarian or non-vegetarian mark, net quantity, date of manufacture or packing, best-before or use-by, batch number, name and address of manufacturer or packer, FSSAI licence number and country of origin for imports.

The green circle mark denotes vegetarian food and the brown circle mark denotes non-vegetarian; the mark must be displayed near the product name.

Standards bodies: BIS issues ISI marks for many products, AGMARK covers agricultural produce grades, Codex Alimentarius sets international reference standards, and ISO 22000 covers food safety management systems.

Sampling and testing use representative samples; microbiological results are reported as colony-forming units per gram or millilitre, and chemical results against the legal maximum limits.

Good Manufacturing Practice covers facilities, personnel, process control and records; Good Hygiene Practice covers cleaning, pest control and personal hygiene; both underpin HACCP.

Cost of production per unit equals total fixed cost plus total variable cost divided by units produced; fixed costs (rent, licence, machinery depreciation) do not change with output, variable costs (raw material, packaging, labour per unit) do.

Break-even quantity equals fixed cost divided by (selling price per unit minus variable cost per unit); break-even sales value equals break-even quantity times selling price.

Contribution margin per unit equals selling price minus variable cost per unit; a product with higher contribution absorbs fixed costs faster.

Working capital is the money tied up in raw material, work-in-progress, finished stock and receivables less payables; food businesses need it for seasonal raw material purchase.

A business plan for a food unit covers product and process, market and competitors, licences (FSSAI, factory, pollution), plant and machinery, manpower, cost estimates, projected profit and loss, and funding sources.

Marketing mix is the four Ps: product (quality, variety, packaging), price (cost-plus, competitive or value-based), place (distribution channels, cold chain) and promotion (advertising, sampling, trade schemes).

Food business support available in Punjab includes schemes of the Punjab Agro Industries Corporation and district industries centres, plus institutional credit from banks under schemes for micro and small enterprises.

Selling price is often set by cost-plus pricing (unit cost plus a markup percentage) or by going-rate and penetration pricing when entering a competitive market.

Personal protective equipment for food plants includes hairnets, beard snoods, clean uniforms, safety shoes, gloves and ear protection in noisy areas; PPE must never become a source of contamination.

Machine safety rules: guards must be in place before starting, never reach into a running machine, power must be isolated and locked out before cleaning or maintenance, and rotating parts must be kept clear.

Common food plant hazards are slips from wet floors, cuts from knives and blades, burns from steam and hot oil, electric shock from wet equipment, and manual handling strain.

Fire safety requires knowing extinguisher types (water, foam, dry powder, carbon dioxide), keeping exits clear, and following evacuation procedures; electrical fires need carbon dioxide or dry powder, never water.

First aid basics: cool burns with clean running water, cover cuts with a detectable blue plaster, and report every injury so that records and corrective action follow.

Waste management follows the hierarchy reduce, reuse, recycle, recover; food waste can be composted or sent to biogas, and effluent must be treated before discharge to meet pollution control norms.

Water and energy conservation measures include fixing leaks, using low-flow cleaning, recovering heat from refrigeration and steam systems, and switching off idle equipment.

Workplace practices include documented standard operating procedures, correct record keeping, reporting hazards, and following the food safety management system at every step.