Food Science and Food Service Management
What it is
Unit I joins the science of food (its chemistry, physics and microbiology) to the management of feeding people at scale. It asks what happens to a food when it is cooked, preserved, coloured, packaged or contaminated, and how a hospital, hostel or canteen plans, costs and safely serves meals. UGC-NET tests named reactions and tests, classifications, preservation conditions, the HACCP principles and simple cost formulas.
Core concepts
Food science, nutrition and properties of food. Food science applies chemistry, physics, microbiology and engineering to food; nutrition studies how the body uses nutrients. Atwater factors are 4 kcal/g for carbohydrate and protein, 9 for fat and 7 for alcohol. Foods are colloids: sol (hot starch paste), gel (jelly), emulsion (oil-in-water milk; water-in-oil butter) and foam (whipped egg white). Water activity (aw) is the food's vapour pressure over that of pure water (1.0); per Frazier, most bacteria need about 0.91, yeasts 0.88 and moulds 0.80. Starch gelatinises on moist heating, retrogrades on cooling (staling, syneresis) and dextrinises under dry heat (toast). Sugar alone caramelises; a reducing sugar plus an amino group gives the Maillard reaction (crust), which costs lysine. Fats go rancid by hydrolysis or by oxidation.
Quality evaluation: subjective and objective. Sensory panels work in booths with samples coded by random three-digit numbers. Difference tests are paired comparison, duo-trio and triangle (three samples, two identical; chance 1/3). Rating uses scales such as the 9-point hedonic scale, from "like extremely" (9) to "dislike extremely" (1). Objective tools: the penetrometer, Warner-Bratzler shear (meat tenderness), viscometer, Hunter colorimeter (L, a, b) and refractometer (°Brix). Chemical tests include proximate analysis, with protein by Kjeldahl (N × 6.25) and fat by Soxhlet. Instruments are reproducible but cannot measure acceptability, so both are combined.
Effects of cooking and processing. Vitamin C is the most labile nutrient; heat, oxygen, alkali, copper and leaching destroy it. Thiamine is lost to heat and alkali (soda in dal); riboflavin is light-sensitive; carotenes oxidise. Steaming and pressure cooking (15 lb/in², about 121°C) conserve nutrients, while discarding cooking water wastes them. Germination raises vitamin C and lowers phytate; fermentation (idli) raises B vitamins. Parboiling drives B vitamins into the rice grain, while polishing and repeated washing remove thiamine.
Food preservation and application. Preservation prevents microbial spoilage, stops the food's own enzymes (blanching) and excludes pests. Pasteurisation kills pathogens only; milk is treated at 63°C for 30 min (LTLT) or 72°C for 15 s (HTST). Low-acid canned foods (pH above 4.6) need about 121°C to destroy Clostridium botulinum spores (the 12D concept). Frozen food is stored at -18°C; quick freezing forms small ice crystals. Freeze drying removes water by sublimation. Sugar and salt preserve by osmosis. Class I preservatives (salt, sugar, vinegar, oil) are natural. Of the Class II preservatives, sodium benzoate suits coloured products and potassium metabisulphite (KMS) light ones, because SO2 bleaches anthocyanins. Gamma irradiation rises in dose from radurisation (shelf life) through radicidation (pathogens) to radappertisation (sterility).
Food pigments and additives. Acid and heat turn chlorophyll into olive pheophytin; soda keeps it green but destroys vitamins. Carotenoids are fat-soluble; beta-carotene is provitamin A, but lycopene is not. Anthocyanins are red in acid and blue-violet in alkali, while anthoxanthins (cauliflower) yellow in alkali. Myoglobin becomes bright-red oxymyoglobin, brown metmyoglobin or, with nitrite, pink cured pigment. Additives serve a technological purpose and carry INS numbers and an ADI: antioxidants (BHA, BHT, tocopherols), emulsifiers (lecithin), stabilisers (pectin, guar gum), sweeteners (aspartame is unsafe in PKU) and MSG. India permits eight synthetic colours as of 2026-10: ponceau 4R, carmoisine, erythrosine, tartrazine, sunset yellow FCF, indigo carmine, brilliant blue FCF and fast green FCF. Metanil yellow is a non-permitted adulterant.
Food standards and microbiological safety. The Food Safety and Standards Act 2006 replaced laws including the PFA Act 1954; FSSAI regulates under it (as of 2026-10). Agmark grades agricultural produce, BIS awards the ISI mark and Codex Alimentarius (FAO/WHO) sets international standards. Intoxications come from preformed toxin: Staphylococcus aureus (heat-stable toxin, onset 1-6 h), C. botulinum (canned low-acid food) and Bacillus cereus (reheated rice). Infections include Salmonella (eggs, poultry) and Listeria, which grows under refrigeration. Aflatoxin (Aspergillus flavus, groundnuts) harms the liver, argemone oil causes epidemic dropsy and khesari dal causes lathyrism. The danger zone is roughly 5-60°C.
HACCP and food packaging. HACCP began in the 1960s with Pillsbury and NASA. Its seven Codex principles: hazard analysis; critical control points (CCPs); critical limits; monitoring; corrective action; verification; records. Five preliminary steps make twelve. A CCP is a step where control is essential to remove or reduce a hazard (cooking, metal detection). Packaging contains, protects, eases use and informs, at primary, secondary and tertiary levels. Materials include glass, tinplate, aluminium, plastics (LDPE, PET), laminates, aseptic cartons and retort pouches. Modified-atmosphere packaging alters O2, CO2 and N2. Active packaging (oxygen scavengers) changes conditions in the pack; intelligent packaging (time-temperature indicators) reports them.
Menu planning and food cost analysis. Menus balance nutrition, budget, clientele, season, equipment and variety of colour, texture and flavour. An à la carte menu prices each item, table d'hôte is a fixed-price set meal and a cyclic menu repeats after a set period. A standardised recipe fixes yield, portion and cost. Cost of food sold = opening inventory + purchases - closing inventory. Food cost % = cost of food sold / sales × 100, and the pricing factor = 100 / target food cost %. Prime cost = food + labour. Break-even = fixed cost / (price - variable cost per unit).
New product development and nanotechnology. Product development runs from idea generation and screening through concept testing, business analysis, prototype and test marketing to commercialisation. Functional foods include probiotics (live microbes that benefit health in adequate amounts) and prebiotics (non-digestible substrates such as inulin). Nanotechnology works at 1-100 nm, through nanoencapsulation for bioavailability and controlled release, nano-silver antimicrobial or nano-clay barrier packaging and nanosensors. The concerns are migration, toxicity and labelling.
Institutional food service. Conventional systems cook and serve on site. Commissary systems cook centrally for satellite units, ready-prepared systems cook and store (cook-chill, cook-freeze) and assembly-serve systems buy prepared food. Hospitals serve therapeutic diets on centrally plated trays or from ward pantries. Schools feed through PM POSHAN, formerly Mid-Day Meal (as of 2026-10). Stores rotate stock first-in, first-out (FIFO).
Research methods: fundamentals and ethics. Research is systematic, controlled, empirical and critical; basic research builds theory and applied research solves problems. Its ethics are informed consent, confidentiality, beneficence and justice (Belmont Report 1979), backed by the Nuremberg Code 1947, the Declaration of Helsinki 1964, ICMR guidelines 2017 and ethics committees. Misconduct is fabrication, falsification or plagiarism.
Worked example
Food cost analysis for a hostel mess (one month). Opening inventory ₹48,000; purchases ₹2,10,000; closing inventory ₹38,000; sales ₹5,50,000; fixed costs ₹1,20,000.
| Step | Working | Result |
|---|---|---|
| Cost of food sold | 48,000 + 2,10,000 - 38,000 | ₹2,20,000 |
| Food cost % | 2,20,000 / 5,50,000 × 100 | 40% |
| Pricing factor | 100 / 40 | 2.5 |
| Thali price (raw food ₹36) | 36 × 2.5 | ₹90 |
| Contribution (variable cost ₹50) | 90 - 50 | ₹40 |
| Break-even point | 1,20,000 / 40 | 3,000 thalis |
Check: 5,50,000 × 0.40 = 2,20,000, and 36 / 90 = 0.40. At 3,000 thalis, revenue (3,000 × 90 = ₹2,70,000) equals cost (1,20,000 + 3,000 × 50 = ₹2,70,000), so profit is zero.
Common traps
- Caramelisation needs only sugar; Maillard needs a reducing sugar plus an amino group, and only Maillard costs lysine.
- KMS bleaches anthocyanins, so coloured squashes take sodium benzoate.
- Pasteurisation is not sterilisation; it kills pathogens only.
- Acid dulls chlorophyll but reddens anthocyanins; alkali brightens chlorophyll but yellows anthoxanthins.
- Food cost % uses cost of food sold (inventory-adjusted), not purchases.
Speed technique
- HACCP order: hazards, points, limits, monitor, correct, verify, record.
- Irradiation by dose: radurisation, then radicidation, then radappertisation.
- Chance in discrimination tests: triangle 1/3, paired and duo-trio 1/2.
- For any price problem, write factor = 100 / food cost %, then multiply.
Check yourself
- Which reaction browns bread crust and lowers available lysine?
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Maillard reaction: a reducing sugar reacts with amino groups. - Why is KMS unsuitable for jamun squash?
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SO2 bleaches anthocyanins: coloured products take sodium benzoate. - In a triangle test, what is the chance of picking the odd sample by guessing?
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One in three: two of three samples are identical. - Which HACCP principle follows determining CCPs?
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Setting critical limits: a limit is needed before monitoring. - At a 40 per cent target food cost, what price suits a dish costing ₹36 in raw food?
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₹90: 100 / 40 = 2.5, and 36 × 2.5 = 90.
Try it: Food Science and Food Service Management questions
Real questions from the NET Home Science bank on exactly this skill. Pick an answer to see the full solution — the intuition, the worked steps, the faster methods and the traps.
In the high-temperature short-time (HTST) method of pasteurising milk, the milk is heated to:
Show the answer and worked solution
Answer: option B
HTST pasteurisation heats milk to 72°C, holds it there for 15 seconds and then cools it rapidly; the older holding (LTLT) method uses 63°C for 30 minutes.
Both methods kill pathogens but not every spore or spoilage organism, which is why pasteurised milk must still be refrigerated.
So HTST pasteurisation uses 72°C for 15 seconds, option B.
In a triangle test used in sensory evaluation, the probability that a panellist picks the odd sample purely by guessing is:
Show the answer and worked solution
Answer: option D
A triangle test presents three coded samples, two identical and one different, and the panellist must identify the odd one.
With three equally likely choices, a guess is right one time in three, so results are judged against a chance level of .
So the chance of guessing the odd sample is , option D.
The Food Safety and Standards Act, which replaced the Prevention of Food Adulteration Act and several other food laws in India, was enacted in:
Show the answer and worked solution
Answer: option C
The Food Safety and Standards Act, 2006 consolidated India's scattered food laws, including the Prevention of Food Adulteration Act, 1954, into a single statute.
The Act created the Food Safety and Standards Authority of India (FSSAI), which frames food standards and regulations under it (as of 2026-10).
So the Act was enacted in 2006, option C.
Read the following Assertion (A) and Reason (R) and choose the correct answer from the given options: Assertion (A) : Potassium metabisulphite (KMS) is unsuitable as a preservative for jamun and other deeply coloured fruit squashes. Reason (R) : The sulphur dioxide released by KMS bleaches anthocyanin pigments.
Show the answer and worked solution
Answer: option A
Assertion: KMS is kept for light-coloured products, and deeply coloured squashes such as jamun are preserved with sodium benzoate instead; the assertion is true.
Reason: KMS releases sulphur dioxide, which bleaches the red-purple anthocyanins that colour jamun, phalsa and similar fruits; the reason is true and is exactly why KMS is avoided there.
So the assertion "Potassium metabisulphite (KMS) is unsuitable…" is true and (R) correctly explains it, option A.
Match the pigments and conditions in List – I with the resulting colours in List – II and choose the correct answer from the options. List – I (Pigment and condition) | List – II (Resulting colour) --- | --- (a) Chlorophyll heated with acid | (i) Pink (b) Anthocyanin in alkali | (ii) Yellow (c) Anthoxanthin in alkali | (iii) Olive green (d) Myoglobin treated with nitrite | (iv) Blue-violet
Show the answer and worked solution
Answer: option B
Acid and heat replace the magnesium of chlorophyll, giving olive-green pheophytin (a – iii); anthocyanins, red in acid, turn blue-violet in alkali (b – iv).
Anthoxanthins, the creamy-white pigments of cauliflower, turn yellow in alkali (c – ii), and nitrite converts meat myoglobin into the pink cured pigment (d – i).
So matching List I, from "Chlorophyll heated with acid", gives a – iii, b – iv, c – ii, d – i, option B.
Answer above — every one shows its working.