CIP Cleaning in Food Production: Chemistry, Process, and HACCP Requirements

Product Recalls Cost from $10 Million. CIP is Insurance That Works Every Shift

In 2023, the FDA recorded 292 food product recalls due to microbiological contamination. The average cost of a single recall for a manufacturer is from $10 million: direct product loss, return logistics, fines, lawsuits, and reputational damage. According to the Grocery Manufacturers Association, a full recall of a major brand costs $30–100 million.

Meanwhile, 60–80% of microbiological incidents in production are related not to raw materials but to insufficient or incorrect equipment cleaning. A 10 µm thick biofilm on the inner wall of a pipeline is a source of Listeria, Salmonella, and E. coli, capable of contaminating tens of tons of finished products in a single shift.

CIP (Clean-In-Place) is the technology that stands between production and these risks. It is not an optional procedure. It is the backbone of food safety, without which an enterprise will not pass any HACCP audit.

What is CIP and Why It Replaced Manual Cleaning

CIP – Clean-In-Place – is equipment cleaning without disassembly. Cleaning solutions circulate in a closed loop: pipelines, heat exchangers, tanks, homogenizers, filling lines. Pumps deliver the solution from the CIP station, it passes through the equipment, and returns (or drains – depending on the configuration).

Before CIP implementation, equipment was cleaned manually: connections were disassembled, brushed, and rinsed with a hose. The problems with manual cleaning are obvious:

• Human factor – the result depends on the operator, their mood, fatigue, and experience
• Inconsistency – each cleaning differs in parameters
• Duration – manual disassembly and assembly of a line takes 2–4 hours versus 45–90 minutes for CIP
• Contamination risk – open equipment is exposed to airborne contamination
• Validation complexity – it is impossible to prove to an auditor that each cleaning is performed identically

CIP solves all this through automation. The CIP station program sets clear parameters for each stage: temperature (±2 °C), solution concentration (controlled by a conductivity meter), circulation time, flow rate (minimum 1.5 m/s for turbulent flow in pipelines). Each cycle is identical to the previous one. This is what HACCP requires: predictability and provability.

5-Stage CIP Cycle: Parameters and Logic of Each Step

The standard full CIP cycle consists of five sequential stages. Each has a clear purpose, and skipping any stage compromises safety.

Stage 1. Pre-rinse

The goal is to flush away the bulk of product residues: milk, juice, beer, meat broth. Water temperature 35–40 °C – no higher. This is critical: at temperatures > 50 °C, proteins denature and “bake” onto the stainless steel surface. Denatured protein is significantly harder to remove than native protein.

Pre-rinsing removes 85–95% of free contaminants. Without it, the alkaline agent is spent dissolving the bulk of the product instead of working on film residues. Chemical savings with proper pre-rinse – up to 30%.

Completion criterion: water at the equipment outlet should be visually clear.

Stage 2. Caustic Wash

The main cleaning stage. Sodium hydroxide (NaOH) at 1–2% concentration and 70–80 °C temperature dissolves:

• Fats – saponification: NaOH breaks ester bonds of triglycerides, forming water-soluble soap
• Proteins – hydrolysis of peptide bonds: casein, albumin, globulin transition into a soluble form
• Starches and sugars – hydrolysis of glycosidic bonds: polysaccharides break down into simple sugars

Temperature 70–80 °C is optimal. At 60 °C, the effectiveness of the alkaline agent drops by 40–50%. At 85 °C and above – unnecessary steam consumption without significant gain, plus accelerated corrosion of seals.

Duration depends on the type of contamination: standard dairy cleaning – 15 minutes, burnt milk on a plate heat exchanger – up to 30 minutes, caramelized sugar – up to 30 minutes with an increase in NaOH concentration to 2.5–3%.

Stage 3. Intermediate Rinse

The goal is to completely remove alkaline solution residues before the acid stage. Control is by pH or conductivity of the outlet water. Rinsing is complete when the pH returns to the level of incoming water (7.0 ± 0.5) or conductivity decreases to background levels.

Why this is critical: mixing alkali and acid is a neutralization reaction. Both reagents are lost, forming a useless salt. And if a chlorine agent enters an acidic environment, gaseous chlorine (Cl₂) – a toxic substance – is released.

Stage 4. Acid Wash

The acid stage removes what alkali cannot – mineral deposits:

• Milkstone – calcium phosphate Ca₃(PO₄)₂ and calcium citrate, formed when milk is heated. Accumulates on heat exchanger plates, reducing heat transfer by 10–15% at a layer thickness of 0.5 mm
• Beerstone – calcium oxalate CaC₂O₄, formed during wort boiling and fermentation. Forms a dense crystalline structure, resistant even to mechanical action
• Water scale – calcium carbonate CaCO₃ and silicates, which precipitate when hard water is heated
• Mineral deposits from juices – tartrates (grape juice), citrates (citrus)

The standard acid agent is nitric acid (HNO₃) at 0.5–1%, temperature 55–65 °C. Nitric acid is chosen for a reason: it is safe for stainless steel (even promotes surface passivation), leaves no residues, and effectively dissolves phosphates and carbonates.

An alternative is phosphoric acid (H₃PO₄): milder, less aggressive, but leaves a phosphate film on the surface. For some applications, this is acceptable, for others, it is not.

Without a regular acid stage, mineral deposits accumulate layer by layer, creating a porous structure – an ideal environment for biofilms that cannot be removed even by aggressive alkaline cleaning.

When a dairy plant approached us with a milkstone problem on their pasteurizer, it turned out they had skipped the CIP acid stage for 3 months “to save time.” Restoring the heat exchanger cost ten times more than all the acid for that period.

Stage 5. Final Sanitization

The final stage is the destruction of microorganisms remaining after chemical cleaning. Cleaning removes contamination; sanitization destroys pathogens.

Peracetic acid (PAA) at 100–200 ppm is the gold standard:

• Effective against bacteria, yeasts, molds, and spores
• Decomposes into acetic acid and water – no-rinse at concentrations up to 200 ppm
• Works at room temperature
• Retains activity in the presence of organic residues
• Does not form toxic byproducts

Chlorine dioxide (ClO₂) at 5–50 ppm is an alternative for water treatment systems and specific areas. A powerful oxidizer, but requires on-site generation (unstable during storage).

Hot water (> 85 °C, 15–20 min) – thermal sanitization. Used in productions where chemical sanitization is undesirable (baby food, UHT lines). Disadvantage – energy intensity.

More details on types of sanitizing agents, rotation, and registration requirements can be found in the article “Industrial Disinfectants”.

CIP Chemistry: What Agents and For What Purpose

Alkaline CIP Agents

The base is sodium hydroxide (NaOH) or potassium hydroxide (KOH). Pure NaOH works, but industrial CIP formulas always contain auxiliary components:

• Surfactants (surface-active agents) – reduce the surface tension of the solution, improving wetting and penetration into surface micro-irregularities. For CIP, low-foam surfactants are mandatory – foam in a closed system creates air pockets and pump cavitation
• Complexing agents (chelators) – EDTA, NTA, sodium gluconate – bind Ca²⁺ and Mg²⁺ ions from hard water, preventing the formation of insoluble precipitates and increasing surfactant effectiveness
• Silicates – additional alkaline buffer, protection of aluminum components from corrosion at high pH
• Corrosion inhibitors – protection of non-ferrous metals if the system contains copper or brass elements

Acidic CIP Agents

The base is nitric acid (HNO₃), phosphoric acid (H₃PO₄), citric acid. Each has its niche:

Sanitizing Agents

PAA (peracetic acid) is the primary agent for CIP sanitization. Why not chlorine? In CIP, chlorine (hypochlorite) at concentrations > 200 ppm is corrosive to stainless steel – the main material of food equipment. PAA at working concentrations is neutral to stainless steel.

Enzymatic Agents

A separate category for specific tasks: removing biofilms formed in “dead zones” of equipment (pipe elbows, valves, seals). Enzymes (proteases, lipases, amylases) destroy the polymeric matrix of the biofilm – polysaccharides and proteins that bacteria use to “attach” to the surface. After enzymatic treatment, bacteria are left unprotected and become vulnerable to standard chemical cleaning.

Enzymatic agents work at moderate temperatures (30–50 °C) and neutral pH (6–8). At higher temperatures or extreme pH, enzymes denature and lose activity.

CIP by Industry: Specifics and Challenges

Dairy Production

Milk is the most demanding product in terms of CIP. Dairy contaminants are a combination of:

• Fat (3–5%) – precipitates on cold surfaces, requires alkaline cleaning
• Casein (2.5–3%) – the most stable milk protein, denatures at T > 65 °C and polymerizes on the surface
• Minerals – calcium phosphate and citrate form milkstone on hot pasteurizer surfaces

CIP frequency: after each production shift (8–12 hours) or when changing products. Pasteurisers – after every 10–12 hours of operation (in HTST mode 72 °C / 15 s). UHT lines (135–140 °C) – after every 6–8 hours due to more intense fouling.

Typical problem: milkstone residues in the crevices of a plate heat exchanger reduce heat transfer. Pasteurization temperature drops by 1–2 °C – the product does not receive the necessary thermal treatment, but the outlet sensor shows “normal” because it was calibrated for a clean heat exchanger.

Brewing

Brewery contaminants:

• Beerstone – calcium oxalate CaC₂O₄, the most persistent mineral deposit in the food industry. Forms during wort boiling and beer storage. Regular acid cleaning (HNO₃ 1%) dissolves it slowly; for severe cases, special formulas with EDTA or a mixture of acids are needed
• Yeast deposits – Saccharomyces cerevisiae residues on the walls of CCTs (cylindro-conical tanks), in transfer pipelines. Alkaline cleaning removes yeast effectively, but with untimely cleaning, yeast sediments are “cemented” by proteins
• Hop resins – iso-alpha acids from hops, forming a sticky film on internal surfaces. Require increased NaOH concentration (2–3%)

Specificity: brewing requires special attention to rinsing. Even minimal residues of alkaline agent (pH > 8) destroy beer foam and alter the taste. The criterion for rinsing quality is pH = 7.0 ± 0.3 or conductivity = ± 10% of the background level.

Juice and Beverage Production

Main contaminants:

• Sugars – sucrose, fructose, glucose. When heated, they caramelize – forming a dense brown film, resistant to standard alkaline cleaning. Requires higher temperature (80 °C) or concentration (NaOH 2–3%)
• Fruit acids – citric, malic, tartaric. Contribute to the formation of mineral deposits (tartrates, calcium citrates) upon contact with hard water
• Pectins and cellulose – form slimy deposits in pipelines. Enzymatic agents (pectinases) are effective but expensive
• Colorants – natural pigments (carotenoids from carrot juice, anthocyanins from berries) can stain plastic and rubber components. Alkaline cleaning with the addition of an oxidizer (hydrogen peroxide or hypochlorite) removes most pigments

CIP frequency: every 4–6 hours at filling temperatures > 20 °C. Sugar solutions are an ideal environment for rapid proliferation of bacteria and yeasts.

Meat Processing Production

The most complex category in terms of hygiene. Contaminants:

• Proteins (blood, collagen, myosin) – rapidly denature and polymerize upon contact with hot water. Pre-rinsing ONLY with cold water (< 35 °C) is a critical rule
• Animal fat – differs from milk fat by a higher melting point (35–45 °C vs. 28–35 °C), requires a higher temperature for alkaline cleaning (75–85 °C)
• Blood – iron-containing hemoglobin protein. Upon contact with sodium hypochlorite, forms persistent stains. Clean with an alkaline agent BEFORE any chlorine sanitization

Regulatory pressure: meat processing is an industry with the strictest HACCP requirements. Cleaning is not just a PRP (prerequisite program) but often a CCP (critical control point). Each cycle is documented with recorded parameters and microbiological control results.

HACCP Requirements for CIP Cleaning

Validation vs. Verification

Two terms that are often confused, but they are fundamentally different:

Validation – a one-time confirmation that the CIP program is capable of providing the required level of cleanliness. Performed when implementing a new program or changing parameters. Includes:

• Determining minimally effective parameters (temperature, concentration, time)
• Microbiological testing after cleaning (swabs from surfaces, ATP test)
• Statistical confirmation (minimum 3 consecutive successful cycles)

Verification – regular confirmation that the validated program continues to work. Performed shiftly or daily:

• Control of CIP station parameters (temperature, concentration, time – automatic SCADA recording)
• Visual inspection of surfaces (by checklist)
• ATP monitoring (rapid test: result in 15 seconds, threshold < 100 RLU)
• Microbiological swabs (selectively, 1–2 times per week)

Documentation

A HACCP auditor checks not only equipment cleanliness but also documentation. Minimum:

1. SOP (Standard Operating Procedure) – step-by-step CIP instructions for each piece of equipment

2. CIP Cycle Log – date, time, parameters (automatic or manual recording), operator

3. Deviation Records – what happened when parameters went out of bounds

4. Corrective Actions – what was done after the deviation (re-cleaning, extended cycle, production shutdown)

5. Validation Records – protocols of initial validation and revalidation (when changing chemicals, equipment, or product)

CCP or PRP?

In most HACCP plans, CIP cleaning is classified as a PRP (prerequisite program) – a mandatory procedure that creates basic conditions for safe production. But in critical areas (aseptic filling, baby food production, RTE products), cleaning can be recognized as a CCP (critical control point) with clearly defined critical limits:

• Caustic wash temperature ≥ 72 °C
• NaOH concentration ≥ 1.5 %
• Circulation time ≥ 15 minutes
• ATP after cleaning < 50 RLU

Deviation from a CCP requires production shutdown until the cause is identified and re-cleaning is performed. The recommendations of Codex Alimentarius (CAC/RCP 1-1969) on general principles of food hygiene are a basic international guideline. Definitions of terms are in the industrial chemistry glossary.

Typical CIP Problems and Their Solutions

1. Insufficient Flow Rate

The minimum solution velocity in pipelines is 1.5 m/s to ensure turbulent flow (Re > 25,000). At lower speeds – laminar flow, and the cleaning solution “slides” through the center of the pipe, not contacting film contaminants on the walls. Symptom: clean straight sections, dirty elbows and expansions.

Solution: check CIP pump performance, valve condition, return line diameter.

2. “Dead Zones” in Equipment

Areas where the cleaning solution does not reach or reaches with insufficient flow: blind pipe branches, incorrectly installed valves, worn gaskets, non-spraying tank heads (spray balls with clogged holes). Biofilms form in dead zones, resistant to standard CIP.

Solution: audit hydraulic scheme, replace blind connections with through-connections, revise spray balls, enzymatic treatment of dead zones once a week.

3. Non-compliance with Temperature Regime

The temperature of the alkaline solution drops below 70 °C due to: insufficient heater power, large heat losses in uninsulated pipelines, mixing with cold water. At 60 °C, the effectiveness of alkaline cleaning drops by 40–50%.

Solution: insulate the CIP circuit, check the heating element, install a temperature sensor on the return line (not just on the supply).

4. Progressive Accumulation of Deposits

The acid stage is skipped “to save time” or shortened to 3–5 minutes. Mineral deposits accumulate gradually, unnoticed. After 2–3 weeks – a noticeable decrease in heat transfer, after 1–2 months – microbiological problems.

Solution: never shorten the acid stage. Effectiveness control – conductivity of the acid solution at the inlet and outlet. If the outlet conductivity is significantly higher, the solution is actively dissolving deposits, and the cleaning time should be increased.

FAQ

Can I manage with only alkaline cleaning without an acid stage?

In the short term – yes, there will be no visible problems. In the long term (2–4 weeks) – mineral deposits accumulate to a level where they are visible on the surface. Milkstone on pasteurizer plates is not only a hygiene problem (biofilms form precisely on the mineral matrix) but also a technical one: a 10–20% reduction in heat transfer increases steam consumption and can lead to under-pasteurization. A full 5-stage cycle is the mandatory minimum for HACCP-certified production.

How often should a CIP program be revalidated?

Standard practice is revalidation annually or when one of the factors changes: replacement of cleaning agent or chemical supplier, change in CIP station parameters, equipment modification (new pipeline section, new heat exchanger), product change (e.g., switching from milk to yogurt – different contamination profile). During revalidation, microbiological tests are repeated after 3 consecutive CIP cycles.

What is the difference between a single-circuit and a dual-circuit CIP station?

A single-circuit (single-use) – the cleaning solution is used once and drained. Simple, but expensive in terms of chemical and water consumption. A dual-circuit (recovery) – the solution returns to the CIP station tank, is filtered, dosed (automatic concentration correction), and reused. Chemical savings – up to 60%, water – up to 40%. Most modern dairy and brewing plants use recovery systems. Critical: reused solution requires regular concentration control and replacement when contaminants accumulate.

How to control CIP effectiveness without a laboratory?

Basic control is possible without a full-fledged laboratory. An ATP luminometer is a portable device that measures the level of adenosine triphosphate (a marker of biological contamination) on a surface. Result in 15 seconds, threshold < 100 RLU for food surfaces. pH test strips – check rinsing quality (pH = 7.0 ± 0.5). PAA concentration test strips – control sanitizer dosing. Visual inspection with a flashlight – basic but effective check. For full HACCP compliance, periodic microbiological swabs will be needed (external laboratory, 1–2 times per week).

SVK CIP Chemistry: Ready Solutions for Your Production

SVK develops and manufactures a full line of CIP agents for the food industry: alkaline and acidic cleaning agents, sanitizing solutions, enzymatic formulas to combat biofilms. Each product is adapted to a specific industry – dairy production, brewing, juice processing, meat processing.

What we offer besides chemistry:

• CIP program selection – analysis of your equipment, product, and water, development of optimal parameters for each stage
• Validation support – assistance in validating the CIP program for HACCP audit compliance
• “Test Drive” program – samples of CIP agents for testing on your equipment with your real contaminants
• Technical support – technologist consultations when changing products, equipment, or regulatory requirements

We work with productions from craft breweries to dairy plants with fully automated CIP stations. More details on types of industrial cleaning agents – in our basic guide.

Get CIP agent samples for testing →

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Read Also

• Industrial Cleaning Agents: Types and Selection – classification, parameters, areas of application
• Industrial Disinfectants – types of sanitizers, rotation, certification
• Requirements for Household Chemicals for Export to the EU – EU regulatory requirements for chemical products
• Glossary of Industrial Chemistry – terms, abbreviations, and definitions