Milk Processing Essentials: Pasteurization, ESL, and UHT

A technical overview of thermal and non-thermal preservation of fluid milk: processes, target organisms, verification, equipment, and packaging

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George N. Stoforos, Ph.D.

Food Process Engineer

Advanced Food-Tech Solutions

gnstoforos@advfood.tech

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Introduction

Milk is a near-neutral, nutrient-dense liquid and an almost ideal microbial growth medium, which makes its preservation one of the most demanding problems in food engineering. Commercial milk processing rests on a validated relationship between a heat — or, increasingly, a non-thermal — treatment, the target microorganism that the treatment is designed to control, and a packaging system that protects the resulting product. The processing objective ranges from a specified reduction of vegetative pathogens (pasteurization) to commercial sterility (UHT), with membrane and high-pressure technologies extending the available toolset.

The design basis is historical as well as microbiological. Early pasteurization standards were developed primarily to control Mycobacterium bovis and M. tuberculosis, before Coxiella burnetii became the accepted reference organism. In 1957, following Q-fever outbreaks traced to raw milk, the U.S. Public Health Service found C. burnetii surviving the existing process and raised the minimum conditions to the 63 °C / 30 min and 72 °C / 15 s combinations still in force today (Enright et al., 1957). A thermal process is only as effective as the reference organism it is designed to inactivate.

This article reviews the principal thermal processes (pasteurization, extended shelf life, and UHT), their target organisms and routine verification; the unit operations used to deliver them (heat exchangers, batch vessels, and homogenizers); the in-container and reduced-water-activity routes used for concentrated and canned milks; and the non-thermal alternative of high-pressure processing. The principal routes, with their storage conditions and typical shelf lives, are summarized in Figure 1.

Figure 1. Principal preservation routes for milk and concentrated milks, with process, package, typical storage condition, and shelf life.

1. Milk as a low-acid food

Product acidity governs the choice of process. At pH ≥ 4.6 a food is classified as low-acid, and low-acid foods can support the germination and growth of Clostridium botulinum and other spore-forming bacteria. Fluid milk sits at approximately pH 6.5–6.7 — unambiguously low-acid (Lewis & Heppell, 2000). This single property partitions milk processing into two regimes: a vegetative-pathogen reduction (pasteurization), which leaves bacterial spores viable and yields a refrigerated, perishable product, and a sterilization (UHT), which inactivates spores to deliver commercial sterility and an ambient-stable product.

Milk composition imposes two further engineering constraints. The fat phase is present as globules of ~3–5 µm that cream under gravity unless reduced in size, which is the rationale for homogenization. Also, several valued constituents — whey proteins, enzymes, and heat-labile bioactives — are thermally sensitive, which is the principal driver behind interest in minimal-heat and non-thermal processing.

2. Pasteurization

Pasteurization is a vegetative-pathogen reduction process. Its reference organism is Coxiella burnetii, currently recognized as the most heat-resistant non-spore-forming pathogen likely to occur in milk. The minimum conditions — 63 °C / 30 min (low-temperature long-time, LTLT) or 72 °C / 15 s (high-temperature short-time, HTST), or 30 min at 145 °F and 15 s at 161 °F, respectively, summarized in Table 1 — are established to deliver at least a 5-log reduction of M. tuberculosis, M. bovis, and C. burnetii in whole milk (Codex Alimentarius, 2004; FDA, 2023). Meeting this criterion also inactivates the other vegetative pathogens of concern — Listeria monocytogenes, Salmonella spp., pathogenic E. coli (including O157:H7), Campylobacter jejuni, Brucella, and Yersinia enterocolitica. Bacterial spores, heat-stable enzymes, and pre-formed heat-stable toxins are not destroyed; pasteurized milk is therefore safe but not sterile, must be held refrigerated, and carries a typical shelf life of roughly two to three weeks. Pasteurization also substantially reduces the spoilage microflora, improving keeping quality, although its regulatory objective remains pathogen reduction rather than spoilage control.

Routine compliance is verified by the alkaline phosphatase (ALP) test. ALP is an enzyme native to raw milk that is inactivated under HTST conditions — by coincidence, at a time–temperature only marginally above that required to inactivate C. burnetii — which makes it an effective process indicator. A negative ALP result confirms both that adequate pasteurization was achieved and that the product has not been re-contaminated with raw milk downstream. The European Union codifies this requirement directly: pasteurization must yield a negative ALP result, defined for cows' milk as ≤ 350 mU/L by ISO 11816-1 (EFSA, 2021; Reg. (EC) No 853/2004); the U.S. Pasteurized Milk Ordinance (PMO) likewise mandates a phosphatase-negative result (FDA, 2023).

2.1  Equipment and configuration

Pasteurization is implemented either as a batch or a continuous operation. The batch (vat) process holds milk at 63 °C for 30 min in a jacketed vessel (steam- or hot-water-heated) that is mechanically agitated, and is used for small volumes and high-fat or cultured products. High-throughput plants use continuous HTST (72 °C / 15 s), in which the most common heating element is the plate heat exchanger (PHE). A PHE comprises a regeneration section that recovers heat from outgoing pasteurized milk to preheat the incoming raw milk (commonly > 90% energy recovery), followed by a heating, holding tube, and cooling section. A temperature-actuated flow-diversion valve at the holding tube exit returns any under-temperature product to the balance tank, ensuring that only milk meeting the time–temperature specification proceeds. Because raw and pasteurized milk are separated in the regeneration section only by thin stainless-steel plates, the U.S. PMO further requires the pasteurized side to be held at least ~1 psi (≈ 7 kPa) above the raw side at all times — maintained by a booster pump under a differential-pressure controller (typically interlocked so the pump cannot run unless the margin reaches ≈ 2 psi / 14 kPa) — so that any plate pinhole leaks pasteurized product toward the raw stream rather than the reverse (Bylund, 2003; FDA, 2023).

An in-line homogenizer is a standard ancillary unit on fluid milk lines. By forcing milk through a narrow valve at approximately 15–20 MPa, it reduces the mean fat-globule diameter to below ~1 µm, which prevents gravity creaming and improves physical stability and mouthfeel. Homogenization is applied across pasteurized, ESL, and UHT lines (in aseptic systems as a sterile, downstream homogenizer); it is a physical refinement of the fat phase and contributes no microbial lethality (Bylund, 2003).

This continuous-processing equipment — plate heat exchangers, homogenizers, flow-diversion valves, and downstream aseptic units — is supplied by a small number of specialist manufacturers, and the appropriate scale depends on the stage of the work. For process development at laboratory and pilot scale, benchtop UHT/HTST systems such as those from MicroThermics reproduce a full commercial process on a few liters, so a thermal process can be established and validated before scale-up. At industrial throughput, the principal suppliers include Tetra Pak, GEA, SPX FLOW, and Alfa Laval; the Tetra Pak Dairy Processing Handbook remains a standard engineering reference for the design of these systems (Tetra Pak, 2025).

3. Extended-shelf-life (ESL) milk

Extended shelf life milk targets a refrigerated shelf life beyond that of conventional pasteurized milk — typically 30 to 90 days — and can be produced by either a thermal or a membrane route. The thermal route is Higher-Heat Shorter-Time (HHST) treatment, designated “ultra-pasteurized” (UP) in the U.S. PMO and defined as heating at ≥ 138 °C for ≥ 2 s (Table 1; Deeth, 2017). Unlike pasteurization, the controlling target is the spore of psychrotrophic bacteria — above all Bacillus cereus, some strains of which are pathogenic, grow at refrigeration temperature, and form heat-resistant spores — together with Paenibacillus spp. (Deeth, 2017). The competing constraint is product quality: the heat load must be limited to avoid the cooked flavor that develops as the whey protein β-lactoglobulin (β-Lg) denatures and releases volatile sulfur compounds.

Deeth (2017) proposes that ESL processing achieve a sporicidal effect of B* > 0.3 while keeping β-Lg denaturation ≤ 50%. B* is the sterilization effect, the integrated lethality of a process expressed relative to a reference of 10.1 s at 135 °C with z = 10.5 °C, for which B* = 1. He concludes that this combination is best met by high-temperature, short-time direct heating with aseptic packaging. For the same sporicidal effect, direct heating (steam injection or infusion, with very rapid heating and cooling) produces markedly less cooked flavor than indirect heating, which transfers heat more slowly across a metal surface (Deeth, 2017). For these higher heat processes, the diagnostic enzyme marker shifts from alkaline phosphatase to lactoperoxidase (LPO), whose inactivation confirms treatment above the standard HTST envelope.

The membrane route is microfiltration (MF), a non-thermal operation that physically removes bacteria, spores, and somatic cells from skim milk through cross-flow ceramic membranes. Membranes of 1.4 µm pore size achieve approximately a 3–4 log reduction of vegetative bacteria and around 4 log of spores, while 0.8 µm membranes can reach up to 6 log spore removal (Elwell & Barbano, 2006; Dairy Foods, 2026). Because the fat globules would otherwise be retained, MF is applied to the skim fraction; the cream is heat-treated separately and recombined. Coupled with a mild pasteurization step, MF yields a fresh-flavored product with a refrigerated shelf life of 60 to 90 days. As with HHST-ESL, the product is not commercially sterile: the extended shelf life is realized only with ultraclean or aseptic filling and an unbroken cold chain; psychrotrophic spore-formers (B. cereus, Paenibacillus spp.) can still limit shelf life (Deeth, 2017).

4. UHT and aseptic processing

Ultra-high-temperature (UHT) processing achieves commercial sterility by continuous-flow heating to approximately 135–150 °C for 2–5 s (EU: not less than 135 °C), followed by aseptic packaging (Table 1; Reg. (EC) No 853/2004). Because milk is low-acid, the target shifts to bacterial spores. The safety reference is Clostridium botulinum, evaluated by the F₀ concept (T_ref = 121.1 °C, z = 10 °C; Table 2), for which a minimum F₀ of 3 min — a 12-D bot-cook process — is generally required. Commercial sterility is validated using the established low-acid food sterilization concepts, while shelf-life stability is often limited by highly heat-resistant thermophilic spore-formers such as Geobacillus stearothermophilus and Bacillus sporothermodurans (Hammer et al., 1995). When commercial sterility is achieved within a sterile package, UHT milk is shelf-stable at ambient temperature for six to nine months.

Two heating configurations are used. Indirect systems transfer heat across a surface using plate or tubular heat exchangers; tubular units tolerate higher pressures and longer run times before fouling. Direct systems inject steam into the product (steam injection) or the product into steam (steam infusion), giving very rapid heating and reduced thermal damage, but require a downstream vacuum flash-cooling step to remove the condensate added during heating (Deeth, 2017; Deeth & Lewis, 2017). Direct heating is typically followed by aseptic homogenization and aseptic filling. Hold-tube design and the associated residence time and lethality calculations are common to both configurations.

The practical limit on UHT shelf life is usually chemical rather than microbial: age gelation. During the high-heat step, denatured β-lactoglobulin complexes with κ-casein at the micelle surface; over months of ambient storage these complexes are released from the casein micelles and cross-link into a three-dimensional protein network, thickening the milk and eventually forming an irreversible gel. Proteolysis accelerates the process — via heat-stable native plasmin (which hydrolyzes β- and αS-caseins) and via heat-resistant bacterial proteases (e.g., those from psychrotrophic Pseudomonas, which target κ-casein) that survive UHT. Because a lower heat load inactivates a smaller fraction of these enzymes, age gelation tends to appear earlier in directly heated UHT milk, and is countered by a preheat-hold step or a higher sterilization temperature (Datta & Deeth, 2001).

5. Concentrated/canned milks: evaporated and sweetened condensed milk

Concentrated milks are produced by removing about half to two-thirds of the water from milk by vacuum evaporation — typically at 60 to 90 °C under reduced pressure, which limits thermal damage to whey proteins — followed by homogenization. The two principal products diverge in how the concentrate is then preserved, and together they illustrate two preservation principles distinct from continuous-flow pasteurization and UHT.

Evaporated milk is an unsweetened concentrate that is filled into cans and sterilized in-container by retort (Table 1). Because the product is low-acid, this is a spore (Clostridium botulinum) process: conditions are on the order of 116 to 118 °C (240 to 245 °F) for approximately 15 min, sufficient to inactivate Clostridium botulinum spores and achieve commercial sterility (Nieuwenhuijse, 2011). In-container sterilization differs from continuous-flow UHT in that the package is sterilized together with its contents, and the retort operates under steam/air overpressure to balance the internal pressure generated within the sealed can. The result is a shelf-stable product with a sealed shelf life of roughly 12 to 18 months; the trade-off is a higher cumulative thermal load than UHT, which produces the characteristic cooked color and flavor (Maillard browning).

Sweetened condensed milk begins with the same concentration step but is preserved by a different principle. A large quantity of sucrose (approximately 45% of the final weight) is dissolved into the concentrate, lowering the water activity (a_w) to approximately 0.80–0.86. At this level, free water is osmotically bound and unavailable to microorganisms, so the product is shelf-stable without a sterilization step: it is pasteurized and hot-filled into pre-sterilized cans rather than retorted (Nieuwenhuijse, 2011). Preservation therefore rests on a water-activity hurdle combined with the hermetic can; the absence of a high-heat sterilization step is why sweetened condensed milk retains a lighter color than evaporated milk.

6. Non-thermal processing: high-pressure processing

High-pressure processing (HPP), or high hydrostatic pressure, is a non-thermal (“cold pasteurization”) technology in which product is subjected to isostatic pressures of roughly 400–600 MPa for 1–5 min at near-ambient temperature. In its most common industrial form, the product is treated after it has been sealed in its final (flexible) package, so HPP also eliminates post-processing recontamination — a significant industrial advantage. HPP inactivates vegetative pathogens and spoilage organisms by approximately 5 log — comparable to thermal pasteurization (600 MPa / 5 min has been reported to deliver 5–7 log reductions) — while largely preserving heat-labile nutrients and fresh sensory character and typically yields a refrigerated shelf life on the order of 20 days (Stratakos et al., 2019).

Two limitations constrain its use for fluid milk. First, bacterial spores are pressure-resistant and are not inactivated by pressure alone, so HPP — like pasteurization — produces a refrigerated, non-sterile product. Second, pressure alters milk's macromolecular structure: casein micelles disintegrate above ~300 MPa and whey proteins denature, changing viscosity, rennet-coagulation behavior, and creaming (Stratakos et al., 2019). Consequently, commercial application to fluid drinking milk remains limited; current use centers on specialty and functional dairy, colostrum, and applications where fresh-like nutritional and sensory quality is the priority. HPP is best viewed as a complementary tool rather than a direct replacement for thermal pasteurization of fluid milk.

7. Regulatory benchmarks and process parameters

Tables 1 and 2 below separate the two questions every milk process raises: what the regulation requires, and which kinetic parameters drive lethality calculations. Table 1 gives the EU and US time–temperature benchmarks; Table 2 gives the reference temperatures, target times, and z-values used to compute lethality in AdvThermaLogic. The pasteurization parameters in Table 2 follow the three-region framework of the IDF Bulletin (IDF, 2022); the °F z-values are obtained from the °C values by the factor 1.8, except in the T ≤ 72 °C region where slightly different fitted values apply. For ESL, a reference temperature of 138 °C with z = 10.5 °C is adopted in preference to the larger nominal z implied by rounded holding-time values in some compilations (IDF, 2022; Deeth, 2017). The small differences between paired °C and °F values are real — they reflect rounding conventions in each jurisdiction's regulation, not a conversion error.

Table 1. Regulatory time–temperature benchmarks for fluid cow's milk (EU vs. US)

Process	United States (Grade "A" PMO)	European Union (Reg. (EC) 853/2004)	Storage & typical shelf life
LTLT / Vat	63 °C (145 °F) / 30 min	63 °C / 30 min	Refrigerated · ~14–21 days
HTST	72 °C (161 °F) / 15 s	72 °C / 15 s, or any equivalent combination	Refrigerated · ~14–21 days
HHST / ESL (Ultra-pasteurized)	≥ 138 °C (280 °F) / 2 s (UP); HHST table for higher temps	High-heat treatment; ESL not separately defined in law (covered by hygiene rules)	Refrigerated · ~30–90 days
UHT + aseptic	Continuous flow, then aseptic fill (21 CFR Part 113)	Not less than 135 °C, short time, + aseptic packaging	Ambient · 6–9 months (unopened)
Microfiltration (+ pasteurization)	Non-thermal; combined with pasteurization under PMO	Physical bacterial removal; combined with heat treatment	Refrigerated · ~60–90 days
HPP (non-thermal)	400–600 MPa, 1–5 min; vegetative-cell control (not a spore process)	Non-thermal alternative; spores survive	Refrigerated · ~20 days

Fat ≥ 10% or total solids ≥ 18% (or added sweeteners) raise the PMO minimum by 5 °F (≈ 3 °C). Pasteurization in both jurisdictions also requires a negative alkaline-phosphatase result (§2).

Table 2. Reference parameters used for lethality calculation (AdvThermaLogic presets).

Process	T_ref  (°C / °F)	Target time / F-value	z-value  (°C / °F)
Pasteurization,  T ≤ 72 °C	72 / 161	15 s	4.33 / 7.70
Pasteurization,  72–90 °C	72 / 161	15 s	8.20 / 14.76
Pasteurization,  ~88.3–100 °C	100 / 212	0.01 s	5.80 / 10.45
ESL (ultra-pasteurization)	138 / 280	2 s	10.5 / 18.9
UHT (aseptic)	121.11 / 250	Fo= 5 min *	10.0 / 18.0

z-values vary by row because each process targets a different kinetic regime: vegetative-cell inactivation in the pasteurization range versus spore inactivation at sterilization temperatures, where the classic z = 10 °C / 18 °F applies. 

*The UHT F-value shown is a common design target; the public-health minimum is F₀ = 3 min, and actual commercial targets vary by manufacturer and product.

Standing requirement: Pasteurized, ESL, microfiltered, and HPP milk must be held refrigerated at every step after processing. The treatment establishes safety; the cold chain preserves it. Only UHT product within intact aseptic packaging is ambient-stable.

8. Process validation

Regardless of the preservation technology used, industrial processors should validate and periodically verify that the delivered process consistently achieves the required microbial reduction under worst-case operating conditions. Time–temperature recording, equipment calibration, flow verification, and routine process monitoring remain essential components of an effective food safety system. Validation establishes that the process, as designed, meets its microbiological target; ongoing verification confirms that it continues to do so in daily operation, where fouling, flow variation, and equipment drift can all erode the delivered lethality. Validation should be repeated whenever the formulation, equipment, package, or intended shelf life changes.

9. Packaging and barrier requirements

The thermal (or non-thermal) treatment and the package constitute a single system: commercial sterility delivered into an oxygen- and light-permeable package is rapidly lost. The barrier and the filling environment must therefore match the intended shelf life.

• Pasteurized milk is distributed cold and turns over quickly, so the package requirements are modest: HDPE bottles, paperboard gable-top cartons (paperboard between polyethylene layers), or PET bottles, providing limited oxygen and light protection sufficient for a two-to-three-week chilled life.

• ESL and microfiltered milk require ultraclean or aseptic filling and a genuine oxygen and light barrier — light-blocking pigmented PET or cartons incorporating an EVOH barrier layer — to realize the longer refrigerated shelf life.

• UHT milk requires a sterile, high-barrier package. The standard format is the multilayer aseptic carton — typically six bonded layers (Figure 2): polyethylene / paperboard / polyethylene / aluminum foil / polyethylene / polyethylene. The aluminum foil provides a near-complete oxygen and light barrier and is the layer that enables ambient, months-long shelf life; aseptic plastic bottles achieve the equivalent function with an EVOH oxygen-barrier layer. The complete aseptic carton systems — filling machine plus carton material — are supplied principally by Tetra Pak, SIG (Combibloc), and Elopak.

As a general rule, the longer and warmer the intended shelf life, the greater the barrier the package must provide, and the more rigorous the hygiene of the filling operation must be.

Figure 2. Exploded barrier structure of a six-layer aseptic carton (outer surface → product side). The aluminum foil is the layer that blocks light and oxygen and enables ambient, months-long shelf life.

10. Concluding remarks

Milk processing is a set of defined unit operations selected to satisfy three coupled requirements:

• Target organism — Coxiella burnetii for pasteurization (covering all vegetative pathogens); psychrotrophic spore-formers such as Bacillus cereus for ESL; thermophilic spore-formers, with C. botulinum as the safety reference, for UHT.

• Shelf-life objective — refrigerated and short for pasteurized, ESL, microfiltered, and HPP milk; ambient and long for UHT.

• Package and filling environment — barrier and hygiene matched to the shelf-life objective.

When these three are aligned, the product meets its specifications from processing line to consumer. A mismatch in any one — commercially sterile milk in a permeable package, an ESL or microfiltration process without aseptic filling, or a UHT product without a full oxygen barrier — allows the weakest element to determine the effective shelf life, regardless of the quality of the preservation step. The concentrated and canned milks extend the same logic with two further preservation principles — in-container thermal sterilization (evaporated milk) and reduced water activity (sweetened condensed milk) — each likewise dependent on an intact hermetic package.

Advanced Food-Tech Solutions recommendation: Treat the preservation step, its verification, and the package as a single specification. Validate and document them together, and re-evaluate all three whenever the product, the target organism, or the shelf-life objective changes.

Appendix A. Worked examples solved with AdvThermaLogic

The following examples are solved in AdvThermaLogic (Pro Edition) — Milk Processing: Pasteurization & Aseptic, Indirect & Direct Steam. In each case, the flow rate, hold-tube geometry, target F-value, and heating system are specified, and the software returns the hold-tube residence time, the flow regime (with Reynolds number), any expansion corrections, and the hold-tube temperature required to deliver the target lethality.

A.1  Pasteurization — indirect system, laminar hold tube

Problem. Milk pasteurization on an indirect system: flow rate Q = 50 gpm through a hold tube 750 in long and 2.37 in internal diameter. Laminar flow assumed. Target: F = 15 s at the 72 °C (161 °F) reference, z = 7.7 °F (≈ 4.3 °C).

AdvThermaLogic output. Residence time (laminar, fastest particle) = 8.59 s; hold-tube temperature required to deliver F = 15 s = 72.71 °C (CFthermal = 1.00).

Interpretation. Under the laminar profile, the fastest element traverses the tube in only 8.59 s — well short of the 15 s reference hold — so the tube must run slightly above 72 °C to still deliver the required pasteurization F-value against Coxiella burnetii. The software solves for that hold-tube temperature directly.

Figure A.1. AdvThermaLogic (Pro Edition) — indirect, laminar pasteurization hold tube: hold-tube temperature 72.71 °C for F = 15 s.

A.2  UHT / aseptic — indirect system, turbulent hold tube

Problem. UHT (aseptic) on the same indirect hold tube (Q = 50 gpm, 750 in × 2.37 in), with the Reynolds number computed for a water-like product (ρ = 997 kg/m³, µ = 0.001 Pa·s). Target: F₀ = 5 min at the 121.1 °C (250 °F) reference, z = 18 °F (= 10 °C), assessed against Clostridium botulinum.

AdvThermaLogic output. Reynolds = 66,520 (turbulent); residence time = 14.32 s; hold-tube temperature required to deliver F₀ = 5 min = 134.33 °C (CFthermal = 1.00). Flow would become laminar only below ≈ 3.0 gpm (Re_crit = 4000).

Interpretation. In the turbulent regime the velocity profile is far flatter, so the fastest element is held 14.32 s rather than the 8.59 s of the laminar case; commercial sterility nonetheless requires ≈ 134 °C to reach F₀ = 5 min in that time.

Figure A.2. AdvThermaLogic (Pro Edition) — indirect, turbulent UHT hold tube (Re = 66,520): hold-tube temperature 134.33 °C for F₀ = 5 min.

A.3  ESL / ultra-pasteurization — direct steam-injection system

Problem. ESL (ultra-pasteurization) on a direct steam-injection system: same tube (Q = 50 gpm, 750 in × 2.37 in), with steam volumetric expansion 12% and thermal expansion 6% applied. Target: F = 2 s at the 138 °C (280 °F) reference, z = 18.9 °F (= 10.5 °C) (Deeth, 2017).

AdvThermaLogic output. The expansions correct the hold-tube flow to Q = 59.36 gpm, giving a residence time of 12.06 s (Reynolds 66,520, turbulent; CFthermal = 1.06, CFsteam = 1.12); hold-tube temperature required to deliver F = 2 s = 129.59 °C, with a minimum preheater exit temperature of 62.92 °C.

Interpretation. Direct steam injection adds condensate, so the true hold-tube flow (59.36 gpm) exceeds the metered 50 gpm and the residence time is shorter. AdvThermaLogic applies both expansion factors when solving for the 129.59 °C hold-tube temperature and reports the minimum preheater exit temperature the system must reach.

Figure A.3. AdvThermaLogic (Pro Edition) — direct steam-injection ESL: flow corrected to 59.36 gpm, hold-tube temperature 129.59 °C for F = 2 s.

AdvThermaLogic (Pro Edition) sizes continuous milk processes directly from line data — from the flow rate and hold-tube geometry it computes the residence time and flow regime (laminar or turbulent, with Reynolds number), applies thermal- and steam-expansion corrections, and solves for the hold-tube temperature required to deliver the target pasteurization F-value or sterilization F₀, for both indirect and direct (steam-injection) systems. Learn more →

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