RBSE SS Voc Food Processing cheat sheet

Food processing is any deliberate operation that changes a raw agricultural commodity into a stable, safe, or convenient food; food science is the study of the physical, chemical, biological, and engineering principles behind those operations.

Unit operations (cleaning, size reduction, mixing, heating, cooling, drying, separation) are the building blocks of every process line; a process flow diagram sequences unit operations with inputs, outputs, and by-products.

Primary processing converts raw harvest into basic forms (milling, pasteurizing, freezing); secondary processing makes ready-to-eat or formulated products; tertiary processing covers ready meals and catering-scale convenience foods.

Material balance: input mass = product mass + waste mass + losses; yield (%) = (product mass / raw input mass) × 100.

Mass balance on a component (e.g., solids): feed mass × feed fraction = sum of (stream mass × stream fraction) for all outputs.

Processing benefits: extended shelf life, pathogen destruction, removal of antinutrients, improved digestibility, standardization, and reduced post-harvest losses (often 20–40% in developing regions).

Processing costs to monitor: nutrient loss (heat-labile vitamins B1, B6, C), sensory change, energy and water use, and generation of solid/liquid waste.

Emerging non-thermal technologies include high-pressure processing (typically 400–600 MPa), pulsed electric fields, cold plasma, ultrasound, and irradiation (Codex permits doses up to 10 kGy for general purposes).

Water activity (aw) is the ratio of water vapor pressure of a food to that of pure water at the same temperature; most bacteria need aw > 0.90, most molds tolerate down to about 0.80, and xerophilic molds down to 0.65.

Macronutrient energy values (Atwater): carbohydrate 4 kcal/g, protein 4 kcal/g, fat 9 kcal/g, alcohol 7 kcal/g, dietary fiber about 2 kcal/g.

Maillard browning occurs between reducing sugars and amino groups of proteins at elevated temperature; it is favored by intermediate aw (about 0.5–0.8) and inhibited by high moisture or low pH.

Caramelization is sugar pyrolysis without amines, requiring higher temperatures (above roughly 150 °C); it is accelerated by acidic and basic catalysts.

Lipid oxidation proceeds by free-radical chain reaction (initiation, propagation, termination); hydroperoxides decompose to aldehydes and ketones that cause rancidity. Antioxidants (BHA, BHT, TBHQ, tocopherols, ascorbate) interrupt propagation.

Enzymatic browning in fruits and vegetables is catalyzed by polyphenol oxidase on phenolic substrates; it is controlled by blanching (heat), ascorbic acid or citric acid (pH), or exclusion of oxygen.

Proteins denature and coagulate on heating; isoelectric point of casein is pH 4.6, which is the basis of acid coagulation in yogurt and cheese.

Starch gelatinization occurs on heating in water (roughly 60–75 °C for many cereal starches); on cooling, retrogradation causes staling of bread and syneresis in gels.

Intrinsic factors controlling microbial growth: pH, aw, redox potential, nutrient content, antimicrobial constituents, and biological structures; extrinsic factors: temperature, relative humidity, atmosphere, and competing microorganisms.

Temperature classes: psychrotrophs grow near 0–7 °C, mesophiles 20–45 °C (optimum ~37 °C), thermophiles 45–70 °C; most foodborne pathogens are mesophiles.

pH limits: most bacteria grow best near pH 6.6–7.5 and are inhibited below pH 4.6; Clostridium botulinum will not grow and produce toxin below pH 4.6, which defines an acidified food.

Clostridium botulinum is an anaerobic spore-former; its toxin is destroyed by heating at 80 °C for 10 minutes or by boiling, but spores require 121 °C (retort) for commercial sterility.

Key foodborne pathogens: Salmonella, Listeria monocytogenes (grows at refrigeration temperature), Escherichia coli O157:H7, Staphylococcus aureus (toxin is heat-stable), Bacillus cereus, Campylobacter, Vibrio parahaemolyticus.

Foodborne illness categories: infection (live pathogen colonizes host), intoxication (preformed toxin, e.g., S. aureus, botulism), and toxicoinfection (toxin produced in gut, e.g., B. cereus, E. coli O157:H7).

HACCP has seven principles: hazard analysis, determination of CCPs, establishment of critical limits, monitoring, corrective actions, verification, and record keeping.

D-values and z-values: D-value is time at a given temperature to reduce a population by 90%; z-value is the temperature change needed to change D-value tenfold. F0 = D121 × (log N0 − log N).

Preservation works by one or more of: reducing microbial load (heat, irradiation, filtration), inhibiting growth (low temperature, low aw, low pH, preservatives, modified atmosphere), or killing/inactivating (sterilization, high pressure).

Blanching uses hot water or steam (typically 70–100 °C for 1–10 minutes) to inactivate enzymes and fix color before freezing or drying; it also removes tissue gases.

Pasteurization targets vegetative pathogens: high-temperature short-time (HTST) milk at 72 °C for 15 s; low-temperature long-time at 63 °C for 30 min; in-pack pasteurization typically 65–85 °C.

Commercial sterilization (e.g., 121 °C, F0 ≥ 3 min for low-acid canned foods) achieves a 12-D reduction of C. botulinum spores; it is a combination of heat and hermetic packaging.

Drying and dehydration: water removal to aw below about 0.60 prevents growth of all microorganisms; drying rate has constant-rate and falling-rate periods.

Freezing: water converts to ice, concentrating solutes and lowering aw; fast freezing gives small ice crystals and less tissue damage; storage at −18 °C is standard, with quality loss from ice recrystallization and freezer burn.

Chemical preservatives include organic acids (lactic, acetic, citric, benzoic, sorbic), nitrite in cured meats (also for color and Clostridium control), sulfur dioxide in dried fruit and wine, and nisin.

Hurdle technology combines several sub-lethal preservation factors (e.g., low pH, aw, temperature, preservative) so the total effect exceeds any single hurdle.

Preservation works by one or more of: reducing microbial load (heat, irradiation, filtration), inhibiting growth (low temperature, low aw, low pH, preservatives, modified atmosphere), or killing/inactivating (sterilization, high pressure).

Blanching uses hot water or steam (typically 70–100 °C for 1–10 minutes) to inactivate enzymes and fix color before freezing or drying; it also removes tissue gases.

Pasteurization targets vegetative pathogens: high-temperature short-time (HTST) milk at 72 °C for 15 s; low-temperature long-time at 63 °C for 30 min; in-pack pasteurization typically 65–85 °C.

Commercial sterilization (e.g., 121 °C, F0 ≥ 3 min for low-acid canned foods) achieves a 12-D reduction of C. botulinum spores; it is a combination of heat and hermetic packaging.

Drying and dehydration: water removal to aw below about 0.60 prevents growth of all microorganisms; drying rate has constant-rate and falling-rate periods.

Freezing: water converts to ice, concentrating solutes and lowering aw; fast freezing gives small ice crystals and less tissue damage; storage at −18 °C is standard, with quality loss from ice recrystallization and freezer burn.

Chemical preservatives include organic acids (lactic, acetic, citric, benzoic, sorbic), nitrite in cured meats (also for color and Clostridium control), sulfur dioxide in dried fruit and wine, and nisin.

Hurdle technology combines several sub-lethal preservation factors (e.g., low pH, aw, temperature, preservative) so the total effect exceeds any single hurdle.

Cereal grain structure: bran (pericarp, aleurone), endosperm (starch and protein), and germ (lipid, vitamins, enzymes); milling separates these fractions and determines flour extraction rate.

Rice milling removes husk (dehusking) then bran (whitening); parboiling (soaking, steaming, drying before milling) drives vitamins into the endosperm and reduces breakage.

Wheat flour quality depends on gluten proteins (gliadin and glutenin); dough develops viscoelasticity on hydration and kneading; damaged starch absorbs water and supports fermentation.

Pulses contain antinutritional factors: trypsin inhibitors and lectins in legumes, phytates, and tannins; soaking, germination, cooking, and fermentation reduce them.

Soybean processing: dehulling, flaking, solvent extraction (hexane) of oil, desolventizing-toasting of meal; toasting inactivates trypsin inhibitor and urease.

Oil extraction methods: mechanical pressing (expeller) leaves 5–7% residual oil; solvent extraction leaves under 1%; refining steps are degumming, neutralization, bleaching, and deodorization.

Rancidity control in oilseeds: low moisture, low temperature, inactivation of lipase (which liberates free fatty acids) and lipoxygenase (which oxidizes polyunsaturated fatty acids).

Extrusion cooking: high temperature short time (often 120–180 °C) with shear; used for snacks, breakfast cereals, and textured vegetable protein; starch gelatinization and protein denaturation occur in the barrel.

Fruits and vegetables are living tissues after harvest: respiration and transpiration continue, so cooling and controlled atmosphere (low O2, elevated CO2) slow deterioration.

Climacteric fruits (banana, mango, tomato, apple) ripen with an ethylene burst and can be ripened or delayed by ethylene management; non-climacteric (citrus, grape, pineapple) do not.

Minimal processing steps: selection, washing, peeling, cutting, blanching (for some), and packaging; cutting increases respiration and enzyme exposure, so refrigeration plus modified atmosphere is needed.

Canning of low-acid vegetables requires pressure retorting (≥ 121 °C) because C. botulinum spores survive boiling; acid foods (pH < 4.6) can be hot-water processed.

Fruit juice processing: extraction, clarification (pectinase, fining agents), pasteurization (typically 90–95 °C for seconds), and deaeration; ascorbic acid addition limits browning and vitamin loss.

Jam and jelly set requires pectin, sugar (about 65% soluble solids), and acid (pH about 3.0–3.4); the setting point is checked by refractometer or sheet test.

Dried fruits (raisins, dates) rely on sun or hot-air drying to aw below 0.60; sulfur dioxide dipping preserves color and limits non-enzymatic browning.

Post-harvest losses are minimized by rapid pre-cooling, careful handling to avoid mechanical injury, and sanitation to limit spoilage organisms such as Penicillium and Botrytis.

Milk composition (cow): about 87% water, 3.5% fat, 3.3% protein (casein ~80%), 4.8% lactose, 0.7% minerals; composition varies with breed, stage of lactation, and feed.

Milk processing sequence: reception and testing, clarification, separation (cream), standardization, homogenization (typically 10–25 MPa), pasteurization or UHT (135–150 °C for 2–5 s), and packaging.

Cheese making: acidification or rennet coagulation, cutting the curd, cooking, draining whey, salting, and ripening; moisture and pH control determine texture and shelf life.

Yogurt is made by fermenting milk with Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus at about 42–45 °C until pH reaches about 4.6.

Meat rigor mortis: post-mortem glycolysis lowers pH to about 5.5–5.7; rigor resolves during conditioning (aging) as proteases tenderize muscle; cold shortening occurs if meat is chilled too rapidly before rigor.

Curing uses salt, nitrite, and often sugar; nitrite forms nitric oxide that binds myoglobin to give cured pink color and inhibits Clostridium botulinum.

Fish spoilage is fast because of high free amino acids, trimethylamine oxide (TMAO) reduction to trimethylamine (the fishy odor), and psychrotrophic bacteria; chilling on ice and rapid freezing are essential.

Poultry processing: stunning, bleeding, scalding (about 50–60 °C), defeathering, evisceration, chilling (water or air), and packaging; Salmonella and Campylobacter control depends on hygiene and temperature control.

Packaging functions: containment, protection from physical, chemical, and biological hazards, convenience, and communication (labeling, traceability).

Barrier properties: oxygen transmission rate (OTR) and water vapor transmission rate (WVTR) determine suitability; metallized films and EVOH provide high oxygen barrier; PE is a good moisture barrier but poor oxygen barrier.

Modified atmosphere packaging (MAP) gas mixtures: red meat about 70–80% O2 with 20–30% CO2; fresh produce low O2 (2–5%) and elevated CO2; bakery and cheese often N2/CO2.

Active and intelligent packaging: oxygen scavengers, ethylene absorbers, moisture regulators, antimicrobial films, and time-temperature or freshness indicators.

Storage conditions to monitor: temperature, relative humidity, light, and stock rotation (first-in first-out); cold chain breakages are the leading cause of quality loss in perishable foods.

Quality assurance tools: good manufacturing practice (GMP), standard operating procedures (SOPs), statistical process control (control charts), calibration, and internal audits.

Shelf-life testing combines microbiological, chemical (e.g., peroxide value, free fatty acids), and sensory evaluation under defined storage conditions; accelerated testing uses elevated temperature and the Arrhenius relationship.

Labeling requires ingredient list in descending order of weight, net quantity, date marking, storage instructions, allergen declaration, and country of origin where mandated.

Cleaning is removal of soil; sanitation is reduction of microorganisms to safe levels; both are needed before disinfection, because organic soil inactivates sanitizers.

Clean-in-place (CIP) uses circulating detergent and sanitizer at controlled concentration, temperature, flow, and contact time; verification uses conductivity, temperature, and rinse-water tests.

Common sanitizers: chlorine (typically 50–200 ppm available chlorine), quaternary ammonium compounds, peracetic acid, iodine, and hot water/steam; efficacy depends on pH, temperature, contact time, and organic load.

Personal hygiene controls: handwashing stations, protective clothing, hair restraints, no jewelry, exclusion of ill workers, and health screening for food handlers.

Pest control and zoning: separate raw and ready-to-eat areas, control air pressure and airflow from clean to dirty zones, and manage drains, condensation, and foot traffic.

Physical hazards include glass, metal, stones, and plastic; control by sieves, magnets, metal detectors, and X-ray inspection; foreign-matter incidents require traceability and recall.

Chemical hazards: cleaning chemical residues, pesticide residues, mycotoxins, allergens, and lubricants; control by separate storage, labeled containers, and rinse verification.

Occupational safety in food plants: guarding of rotating equipment, lockout/tagout, hot-surface and steam protection, safe use of ammonia refrigeration, and confined-space entry procedures.

Business plan essentials: product description, market analysis, process and capacity plan, raw material sourcing, capital and operating cost estimates, break-even analysis, and regulatory compliance plan.

Break-even quantity = fixed costs / (selling price per unit − variable cost per unit); contribution margin ratio = (price − variable cost) / price.

Working capital in food processing is tied to raw material seasonality, inventory holding, and receivables; perishability raises the cost of holding stock.

Market segmentation for food products commonly uses demographics, income, region, dietary preference, and channel (retail, food service, export).

Codex Alimentarius provides international standards, codes of practice, and maximum residue limits; it is the reference for trade disputes under the WTO SPS Agreement.

National food law typically establishes a food safety authority, licensing and registration of food businesses, mandatory standards, labeling rules, and enforcement powers.

Food additives are regulated by permitted lists with maximum levels; preservatives, colors, and sweeteners must be declared on the label and must be justified by technological need.

Traceability and recall: one-step-back one-step-forward records allow withdrawal of affected lots; a recall plan defines decision authority, communication, and effectiveness checks.