Clean-in-Place Systems: Design, Regulation, and Equipment Selection

Clean-in-place (CIP) cleaning has shifted from industry best practice to regulatory obligation. In food, dairy, beverage, and pharmaceutical manufacturing, CIP is now a documented preventive control — one that must be validated, monitored, and verified under both US and European regulatory frameworks. For New Zealand manufacturers supplying export markets, that alignment has direct commercial consequences.

How CIP Works: The Five-Phase Cleaning Cycle

CIP describes the automated cleaning of process equipment — mixers, tanks, pipework, sieves, filling lines, conveyor systems — without disassembly. Cleaning solutions are circulated under controlled conditions of temperature, chemical concentration, flow velocity, and contact time. A standard sequence follows five phases:

1. Pre-rinse — Potable water (or the reclaimed final rinse from the previous cycle) flushes loose product residue and warms the system.
2. Caustic wash — Sodium hydroxide (NaOH) solution at 0.5–2.0% concentration and 55–66°C dissolves fats, proteins, and carbohydrates. A minimum flow velocity of 1.5 m/s is required to achieve turbulent flow — the mechanical scrubbing action that lifts dissolved soil from surfaces.
3. Intermediate rinse — Potable water removes caustic residues before the next phase.
4. Acid wash — Nitric or phosphoric acid at 0.5–1.0% removes mineral scale and neutralises residual alkalinity. This phase is critical in dairy and beverage applications where calcium and magnesium deposits accumulate rapidly.
5. Sanitising rinse — A low-concentration sanitiser — chlorine-based, peracetic acid, or hot water — reduces the microbial load on food-contact surfaces to acceptable levels before the next production run.

Each parameter must be validated against the specific equipment geometry, product type, and hygiene risk. A recipe adequate for a stainless steel tank may be wholly insufficient for a complex multi-port manifold with potential dead legs or spray shadow zones.

Russell Finex Compact Sieve

Regulatory Requirements: FDA and the EU

In the United States, CIP systems fall under FSMA’s Current Good Manufacturing Practice (cGMP) rule, codified at 21 CFR Part 117. Under this framework, sanitation is a preventive control: written procedures must be established, cycle parameters recorded — time, temperature, chemical concentration, and flow rate — and completion verified through documented testing. Verification is typically performed using ATP bioluminescence swabbing of food-contact surfaces, with acceptance thresholds defined in advance.

Records must be retained for a minimum of two years under 21 CFR 117.190. With FSMA Section 204’s traceability requirements at full enforcement, the chain of evidence linking a CIP event to a specific production batch is subject to increasing regulatory scrutiny.

In Europe, the foundational instrument is Regulation (EC) No 852/2004 on the Hygiene of Foodstuffs, which requires that equipment in contact with food be designed and maintained to permit adequate cleaning and, where necessary, disinfection. HACCP principles must be integrated from the design phase, not retrofitted.

The European Hygienic Engineering & Design Group (EHEDG) provides the technical implementation framework: EHEDG Guideline Document 8 sets out hygienic design criteria for closed equipment intended for CIP cleaning.

For New Zealand manufacturers, these standards have direct practical relevance. MPI’s Animal Products Notice: Production, Supply and Processing 2025 requires documented cleaning and sanitation procedures for registered dairy processors. Beyond domestic compliance, any manufacturer supplying EU or US markets is subject to the import standards of those markets. Specifying EHEDG-certified or 3-A-compliant equipment is not a premium — it is the baseline expected by auditors and buyers operating under BRCGS or FSSC 22000 certification schemes.

A Dinnissen Total System Integration Solution.

Equipment Design for CIP: Where Problems Begin

CIP failure is rarely a chemistry problem. It is almost always a design problem. Common failure points include:

• Dead legs — Sections of pipework with insufficient flow to achieve turbulent cleaning. Any pipe run more than 1.5× its internal diameter from the main flow path is a potential dead leg under 3-A Standard criteria.
• Spray coverage — Fixed spray balls or rotating spray heads must provide complete coverage of all internal surfaces. Shadow zones — areas out of direct spray contact — harbour biofilm and resist CIP cleaning.
• Drainage — Equipment must slope to drain completely. Retained liquid between cleaning cycles creates conditions for microbial multiplication and undermines sanitiser efficacy.
• Surface finish — Internal Ra values of ≤0.8 µm (electropolished) are typically required for product-contact surfaces in pharmaceutical and dairy applications. Rougher finishes create crevices that shield bacteria from cleaning solutions.

These design criteria are assessed as part of EHEDG and 3-A certification. Equipment that meets these standards is inherently easier to validate and reduces the CIP qualification burden for the end user — a practical consideration when commissioning new lines or expanding capacity.

Allergen Management and CIP

FSMA’s preventive controls rule explicitly identifies allergen cross-contact as a hazard requiring preventive control. CIP is the primary means by which allergen residues are removed from shared-use equipment between product runs. However, CIP validation for allergen removal is separate from, and in addition to, microbial sanitation validation. The caustic wash phase is generally effective against protein-based allergens — milk, egg, soy, wheat — but carry-through risk increases with equipment geometric complexity. Facilities processing multiple allergen-containing products must validate CIP effectiveness for each allergen transition, a requirement that is increasingly enforced under both US and EU auditing frameworks.

Hanningfield Capsule Conveyor

APS Partner Equipment and CIP Design

The APS partner portfolio covers the principal equipment categories where CIP design directly affects hygiene outcomes and regulatory compliance:

• Silverson Machines — High shear mixers engineered for rapid CIP. The rotor/stator head design generates high flow velocity through the mixing zone, preventing localised residue accumulation. Pharmaceutical and food-grade variants meet EHEDG and 3-A hygienic design criteria and include sanitary clamp fittings and polished product-contact surfaces.
• Russell Finex — Vibratory sieves and Liquid Solid Separators™ with hygienic frames and sanitary clamp connections designed for CIP cleaning. The open-frame construction minimises dead zones and facilitates complete drainage.
• Dinnissen — Batch mixing and powder handling systems where wet CIP is applicable to liquid and semi-liquid applications, and clean-out-of-place (COP) protocols are used for dry powder handling. COP is the appropriate method where water ingress into dry powder systems would compromise product or equipment integrity.
• Hanningfield — Pharmaceutical powder handling equipment — cone mills, vacuum transfer systems, blenders — designed to GMP and EHEDG standards. Surface finishes and sealed bearing arrangements support validated cleaning protocols across the oral solid dosage (OSD) processing line.
• Wire Belt and Ashworth Brothers — Open-mesh stainless steel conveyor belts designed for high-pressure washdown and CIP compatibility. The open construction — minimal contact points, full drainage, no trapped product zones — is a deliberate hygienic design feature. Wire Belt’s Flat-Flex® and Ashworth’s SpiralSurf® belts are engineered to withstand repeated chemical exposure and drain freely after each cleaning cycle.
• Filtec — Liquid filling machines with stainless steel product-contact fluid paths and hygienic seal arrangements. CIP-compatible circuits are standard on the gravity and flow meter filling ranges.
• Zalkin — Capping and cap handling systems with hygienic product-contact surfaces and automated cleaning capability for cap track and filling head components.

Planning CIP Into New Equipment Specifications

CIP should be considered during equipment selection, not after installation. Key questions to address at specification stage: Does the equipment geometry allow for turbulent flow throughout the entire fluid path? Are all spray positions documented and verifiable? Can the chemical resistance of seals, gaskets, and surface coatings be confirmed for the intended CIP chemicals and concentrations? Has the manufacturer provided a validated CIP recipe, or will the end user need to develop and validate one independently?

Retrofitting CIP capability to equipment not designed for it is costly and frequently incomplete. Dead legs that cannot be eliminated, drain points that cannot be repositioned, and surfaces that cannot be adequately polished remain as persistent hygiene risks regardless of how rigorous the cleaning regime.

APS works with customers at the specification stage to ensure that equipment selection accounts for CIP design requirements from the outset. Contact us to discuss your processing environment and cleaning validation requirements.