Food Technology and Process Engineering

Precision fermentation scale-up usually fails on physics, not biology. As vessels grow, oxygen transfer, OTR = kLa(C* − C), must keep pace with the culture’s oxygen uptake, metabolic heat of about 460 kJ per mole of oxygen must leave through less wall area per litre, and longer mixing times create gradients.

Novel food process validation is evidence that HPP, PEF, UV-C or another non-thermal step, run at its critical limits, achieves the required log reduction of the target pathogen in the real product. It rests on worst-case formulations and settings, resistant strains or proven surrogates, directly measured kinetics and production controls traced back to the study.

An MVR evaporator compresses its own vapour with an electric fan and reuses it for heating, using roughly 10 to 20 kWh per tonne of water. A single effect needs about 1 kg of steam per kg of water; each added effect raises steam economy by roughly one, and TVR adds about one more.

Clean in place (CIP) cleans pipes, tanks and heat exchangers by circulating water and chemicals without dismantling. It works when time, temperature, chemical action and flow are all adequate: typically pre-rinse, caustic wash, rinse, acid wash, final rinse and sanitise, with about 1.5 m/s or more in pipes, verified by records, ATP and microbiological swabs.

Non-Newtonian fluid pumping starts with a flow curve, not a single viscosity. Fit the power law τ = K·γ̇ⁿ, correct the wall shear rate, calculate laminar pressure drop from ΔP = 4·τw·L/D, check NPSH available against the pump’s requirement, and use positive displacement pumps for viscous foods.

Thermal process validation is documented evidence that a scheduled heat process delivers the target lethality at the slowest-heating point of the worst-case container. For low-acid canned foods that means at least a 12D botulinum cook (F0 about 3 min), proven by temperature distribution and heat penetration studies and calculated with the General Method.

Pasteurisation vs UHT vs HPP comes down to what each process kills. Pasteurisation and HPP kill vegetative microbes but not bacterial spores, so products stay chilled. UHT with aseptic packing and retorting destroy spores, giving commercially sterile food that keeps for months or years at room temperature, with more cooked flavour.

A plate heat exchanger passes two liquids through alternate channels between thin corrugated plates, usually in counter-current flow. Size it with Q = m·cp·ΔT and Q = U·A·LMTD. In a milk pasteuriser, regeneration supplies around 90% of the temperature rise, and the pasteurised side must run at a higher pressure than the raw side.

OEE in food manufacturing is availability × performance × quality: the share of planned production time that becomes good product at full speed. Together with yield, give-away and changeover time, it sets the raw material and conversion cost of every pack and shows where spare capacity is hiding.

A mass balance in food processing applies one rule: what goes in must come out or accumulate. Write a total balance and one for a key component, such as fat in milk or dry solids in drying, then solve. Never subtract wet-basis moisture percentages; anchor drying and evaporation on the dry solids.