In falling-film evaporators operating on whole milk, skim milk, and whey streams, KM-73E is injected into the feed balance tank or upstream of the first effect at a rate of 20–150 mg/kg as-delivered emulsion relative to liquid feed volume, after dilution with potable water at a ratio between 1:5 and 1:20. The diluent temperature must remain below 25 °C; higher water temperatures accelerate droplet coalescence and form hydrophobic oil slicks that foul downstream plate heat exchangers and ultrafiltration membranes. The injection point is upstream of a static mixer or in the suction line of a sanitary centrifugal pump, and the metering pump is a positive-displacement diaphragm type rated for 0.5–10 L/h against line pressures up to 10 bar. In dairy evaporation, the silicone emulsion destabilizes protein-stabilized foam lamellae in the vapor/liquid separator, preventing entrainment losses and maintaining the design thermal driving force across the calandria bundle. A fall in the overall heat-transfer coefficient of the first effect from 2.5 kW/m²·K to 2.0 kW/m²·K has been observed on production-scale falling-film units when uncontrolled foam carryover reduces tube wetting; the same loss increases specific steam consumption and shortens operating cycle time before cleaning. In the spray dryer, KM-73E is metered into the concentrate feed line at the same concentration range, where it prevents air incorporation in the high-pressure nozzle or rotary atomizer feed. Air bubbles in the atomizer feed cause irregular droplet formation, increase wall fouling, and reduce bulk powder density. Emulsion droplet size should be confirmed by laser diffraction before use; D50 values in the 10–40 µm range are compatible with standard dosing pumps, while larger droplets above 100 µm may block narrow low-rate feed nozzles. The finished products include whole milk powder, skim milk powder, whey powder, and demineralized whey permeate powder. Compliance is verified under 21 CFR 173.340 in the United States; the residual polydimethylsiloxane in the finished dry product is controlled by the statutory carryover limits for the designated food category. Supplier certificates of analysis should confirm active silicone content and the absence of nonpermitted preservatives before release to the production line.

A compliance verification framework for the addition points described in the following process streams is summarized below.

When raw sugar beet juice is clarified and transferred to the first effect of a quintuple-effect evaporator, foam stabilization arises from saponins, betaine, pectin fragments, and denatured protein. KM-73E is added to the clarified juice receiver at 5–50 mg/kg as-delivered emulsion, corresponding to a low active-silicone dose in the range of 0.5–5 mg/kg juice when the batch silicon content is accounted for. The treated juice is then pumped through plate heat exchangers into the first effect. The defoamer should not be injected before crossflow membrane clarification if polyethersulfone or ceramic ultrafiltration membranes are used, because emulsion droplets can adhere to the membrane surface and reduce permeate flux by 15–25 % after 4–6 h of continuous operation. In sugar vacuum pans, the same addition rate is used to control foam in the masseuite during crystallization; foam accumulation in the calandria zone lowers heat transfer and produces uneven crystal growth. The addition point in vacuum pans is the circulating massecuite line, not the direct steam line, to prevent thermal breakdown of the emulsion. Vacuum pan operation typically proceeds at absolute pressures of 0.1–0.2 bar and masseuite Brix values from 78 to 92, conditions that require a defoamer with stable emulsion structure under low pressure and high viscosity. Finished products include white refined sugar, refined beet sugar, and cane mill white sugar. Regulatory compliance in European processing facilities depends on national processing-aid authorization under Regulation (EC) No 1333/2008; United States use is reviewed under 21 CFR 173.340. Process water removed from evaporator condensate may contain trace silicone carryover, and that condensate should be directed through a polishing separator before reuse in extraction or diffusion batteries.

Why Does Antifoam Concentration Shift kLa in Aerobic Fermentation Vessels?

In fed-batch and continuous aerobic fermentation of yeast, specialty enzymes, and citric acid, KM-73E is introduced through a sterile addition port after autoclaving or through a peristaltic pump equipped with a 0.2 µm sterile filter, at cumulative addition rates from 0.05 g/L to 0.5 g/L of working volume. The addition strategy is typically split between an initial charge at 0.05–0.1 g/L and subsequent automated bolus additions triggered by foam sensor contact. Foam control in stirred-tank reactors with Rushton impellers and ring spargers is necessary to prevent headspace carryover into the exhaust gas line and to protect the outlet gas condenser from siloxane accumulation, but excess silicone coalesces air bubbles and reduces the volumetric oxygen transfer coefficient. Published data for specific biological systems is limited; however, process-development studies using dynamic gassing-out methods show that kLa can decline by 10–30 % when antifoam concentration exceeds the critical coalescence point for a given broth formulation. For this reason, addition is controlled by dissolved-oxygen feedback, not by elapsed time. The emulsion should not be combined with cationic polyelectrolyte flocculants in the same feed line because electrostatic destabilization causes silicone oil droplet separation and fouling of sterile filters. In yeast cream separation, silicone residues are removed with the spent medium and do not affect the finished yeast or enzyme preparation when standard washing is applied. Compliance is assessed under 21 CFR 173.340 and the Food Chemicals Codex monograph for dimethicone. Finished products include baker’s yeast, brewer’s yeast, glucose isomerase, amylase preparations, citric acid, and probiotic cultures.

Hot-water blanching of cut root vegetables and leafy greens releases starch and pectin that form a foam layer trapping soil, sugars, and fine particulates in the blancher overflow and rotary drum washers. KM-73E is metered into the recirculated process-water manifold at 5–30 mg/L as-delivered emulsion, with the injection point located after the fines screen and before the heat exchanger to ensure dispersion. The treated water is reused across the washing and blanching stages, and the defoamer maintains hydrocyclone solids-removal efficiency by preventing air-stabilized fines from floating over the weir. Excessive addition above 50 mg/L in the wash water causes silicone droplet deposition on the product surface and interferes with downstream freezing belt release; the defect is visible as white spots on IQF frozen cut surfaces. The emulsion should not be injected into undiluted peracetic acid sanitizing stock solutions, because the low-pH environment can crack the emulsion and produce free silicone oil in the sanitizer recirculation line. Finished products include IQF green beans, diced carrots, cut leafy greens, frozen spinach, and canned pulses. In the United States, use is regulated under 21 CFR 173.340; for European production lines, the relevant national processing-aid law and carryover calculation should be recorded in the HACCP plan. Process water is discharged or treated anaerobically, and silicone antifoam is partially retained in the sludge phase; the site waste-treatment operator should confirm that silicone-containing sludge does not exceed the local contract limit for incineration or land application.

CIP Return-Foam Collapse and Bottle Rinser Carryover

Carbonated soft drink, juice, and bottled water lines operating CIP return tanks generate foam from hot alkali, saponified fatty soils, and entrained air; without defoaming, the return pump cavitates and cleaning-fluid velocity falls below the 1.5 m/s minimum required for turbulent flow. KM-73E is added to the CIP return tank at 5–50 mg/L of recirculated cleaning solution, typically after the return-line sight glass and before the tank inlet. The addition point avoids direct contact with concentrated sodium hydroxide solution; the emulsion is prediluted with 1:10 potable water and injected through a stainless-steel eductor to prevent high-pH shock destabilization. In bottle rinser applications, foam carryover into the filler bowl is controlled at 5–20 mg/L rinsing water, which prevents fill-level variation from foam-induced bubble inclusions and maintains net weight control within the filler calibration tolerance. The defoamer is rinsed from packaging surfaces by the final potable-water rinse; residual silicone on the container is below the practical detection limit for standard gravimetric methods when rinse water flow is above 1.5 L/min per nozzle. The cleaning solution and rinse water are discharged to drain or treated by the plant wastewater neutralization system. Finished products include carbonated soft drinks, fruit juice, sports drinks, and bottled water. Compliance for use in cleaning solutions that contact food-contact surfaces is reviewed under 21 CFR 173.340; the user should verify that the cleaning chemical supplier accepts the defoamer under the CIP program and that the final rinse satisfies food-contact sanitization requirements.

Starch, pectin, and protein released from cut surfaces in potato flume and wash-water systems create a dense foam that reduces the separation efficiency of hydrocyclone batteries and clogs the slots of static screens. KM-73E is introduced into the flume water at 5–30 mg/L and into the starch recovery water at 10–40 mg/L, after the primary solids separator and before the hydrocyclone feed pump. The defoamer accelerates foam drainage in the secondary starch separation step, allowing granular starch to settle by gravity in spiral classifiers and decanter centrifuges. A production-scale observation in a plant running a 10 t/h potato line showed that uncontrolled foam in the hydrocyclone feed reduced starch recovery by 8–12 % and increased suspended solids in the recycled process water; the same line recovered starch yield within specification after installation of a proportional dosing pump linked to foam level. Overdose above 50 mg/L causes free silicone oil to coat starch granules and alter the Brabender amylograph peak viscosity of the recovered starch; such starch may be rejected for use in clean-label food products. The process water after treatment is reconditioned through a dissolved air flotation unit, where silicone partitions into the float sludge. Finished products include frozen French fries, potato flakes, potato starch, and potato protein. Compliance in the United States is based on 21 CFR 173.340; fertilizer or animal-feed use of the recovered starch sludge requires confirmation that silicone content remains within the feed contract specification.

Retort kettle cooking of starch-thickened sauces, dairy-based soups, and gravies introduces steam injection and mechanical shear, producing foam that can persist in the headspace before seaming and cause container underfill or sauce particle misdistribution. KM-73E is added to the batch kettle at 10–100 mg/kg of product mass, using a pre-emulsion diluted with 1:5 water and introduced through the small ingredient port or the vortex of the mixer. The defoamer controls the foam height during heating from 60 °C to 95 °C and during steam injection at pressures up to 2 bar, preventing starch gel foam from entering the vent line and reducing splashing losses on the kettle walls. In aseptic processing lines, the addition point is located before the deaerator to prevent air bubbles from passing through the tubular heat exchanger and reducing the lethal rate; excessive air in the product flow causes temperature probe oscillation and may trigger the automatic divert valve. The emulsion should not be used in oil-continuous formulations containing more than 30 % oil phase without a compatibility test, because silicone partitioning into the oil phase can reduce defoaming performance in the aqueous phase. Finished products include retorted soups, pasta sauces, dairy-based gravies, and high-protein liquid meal formulations. United States regulatory status is reviewed under 21 CFR 173.340; for export to European markets, the carryover of polydimethylsiloxane is evaluated under the relevant national processing-aid regime and recorded in the product specification.