Food Ingredients: Hygienic Level and Batch Measurement

Technical guide by Arvin, METRAVON Instruments · Reviewed September 2026

Short answer

A food or ingredient measurement system must be accurate enough for its task, cleanable under the plant's validated procedure and traceable to the production batch. Evaluate continuous level for raw-material inventory, point-level protection for overfill or starvation, and weighing for recipes. Confirm product-contact materials, surface and seal requirements from the project hygiene specification; do not infer food-contact or hygienic certification from a general product page.

Powders, pellets, oils, syrups and liquid flavors present different measurement and cleaning problems. Document production, cleaning and changeover as separate operating conditions before selecting the instrument or scale.

Define the required result

Product-contact and hygienic requirements

Identify every component that may contact product, vapor, condensate or cleaning fluid. Confirm material grade, surface finish, gasket, process connection, drainability and documentation required by the destination market and plant standard. The boundary must be agreed by the hygienic-design authority; a non-contact sensing principle does not automatically place the antenna and connection outside the product-contact zone.

Avoid dead legs and inaccessible pockets around nozzles, guards, flexible connections and weigh hoppers. Provide enough space to inspect, remove and reinstall components without damaging seals or changing the mechanical load path.

Powder and bulk-solid silos

Flour, starch, sugar, salt, grain and premixes differ in dust, moisture sensitivity, adhesion and angle of repose. For non-contact radar, record silo geometry, inlet, internal braces, filter or extraction flow, maximum surface peak and expected buildup. Mount away from the filling stream and confirm performance while filling.

When converting level to mass, use a verified vessel table and product-specific bulk density. Aeration, compaction and moisture can change density. Preserve the original level value so inventory differences can be investigated without losing the measurement source.

Liquid ingredient tanks

Oils, syrups, concentrates and flavor solutions may create foam, coating or condensation. Confirm viscosity, dielectric behavior where available, process and cleaning temperatures, pressure or vacuum, agitation, vapor and nozzle geometry. Review the most severe cleaning condition separately from normal production.

If clean-in-place or steam-in-place operation is required, specify the media, concentration, temperature, pressure, duration and cycle frequency. Suitability must be confirmed from the exact model, seal and installation documents; the presence of a radar measurement principle is not evidence of CIP or SIP compliance.

Batch weighing and minor ingredients

Define minimum and maximum targets, allowable error, resolution, cycle time and the consequence of an out-of-tolerance dose. A small additive target may be too close to the useful division of a large main-ingredient scale. In that case, evaluate a dedicated smaller scale, loss-in-weight feeder or validated premix method.

Control coarse and fine feed, material in flight and settling time. Verify multiple consecutive batches at the smallest, typical and largest targets. Test realistic refill conditions because changing head pressure and feeder state can alter flow and overshoot.

Allergens, changeover and cleaning

• Define the previous and next product, allergen status and validated cleaning procedure.
• Record cleaning completion, inspection or test result and release authorization.
• Prevent retained product in hoppers, valves, flexible connections and feeders from bypassing the changeover record.
• Keep manual additions and corrections visible in the final batch history.
• Confirm combustible-dust classification and protection for sugar, flour, starch and other relevant powders.

Traceability and data integration

Use a stable batch identifier across recipe, PLC, scale and production records. Store recipe name and version, raw-material lot, target and actual quantity, tolerance result, equipment identity, operator action, alarm and timestamp. Define which system owns the recipe and how an approved change reaches the controller.

Local dosing and protection should continue safely during a network outage. Specify offline buffering, resubmission and duplicate prevention. Never overwrite an original actual value with a corrected value; retain the correction, reason, user and time as a separate audit event.

Commissioning and acceptance

1. Verify product, hygiene specification, contact materials, seals, process connections and required certificates.
2. Test level measurement with representative product during filling, discharge and cleaning conditions.
3. Calibrate each weighing range and run repeated minimum, normal and maximum batches.
4. Challenge overfill, low-level, device-fault, power-loss and communication-loss responses through the full system.
5. Perform a representative product or allergen changeover and verify the cleaning and release record.
6. Trace one finished batch back to recipe version, ingredient lots, actual weights, exceptions and operator actions.

Information required for selection

Provide ingredient names and physical form, allergen and hygiene requirements, bulk density or liquid properties, dust, foam and adhesion; silo or tank drawings; process and cleaning temperature and pressure; minimum batch and tolerance; contact materials and certificates; hazardous-area classification; recipe and batch-record fields; and PLC, MES or remote-platform interfaces.

Frequently asked questions

Is non-contact radar automatically hygienic?

No. The antenna, process connection, gasket, condensate behavior, drainability and cleaning method still require review against the project's hygiene standard.

Why use a separate scale for minor ingredients?

A large scale may not provide enough usable resolution or feeder control at the smallest target. A dedicated range can make accuracy and repeatability easier to verify.

Can radar measure a foaming syrup?

It may be possible, but foam type, thickness, coating, agitation and condensation must be assessed. Use representative process testing when uncertainty remains.

What must a traceable batch record contain?

At minimum, keep batch identity, recipe version, ingredient lot, targets, actuals, tolerance results, timestamps, alarms and manual interventions under controlled access.

Convert food-safety needs into design requirements

List every ingredient, allergen status, physical form, cleaning method and permitted contact material. Define whether equipment is dry-cleaned, wet-cleaned, cleaned in place or dismantled. Hygienic suitability depends on surface finish, geometry, drainage, seals and installation, not simply stainless-steel construction. Identify regulatory and customer standards for the destination market.

Determine where product can collect around nozzles, guards, probes and flexible connectors. Avoid crevices and horizontal ledges. A non-contact radar reduces product contact but its process connection can still retain dust or receive condensation and cleaning spray. Confirm that inspection and removal are possible without contaminating the process.

Ingredient storage and stock accuracy

Use continuous level for availability and trend, independent switches for critical overfill or low level, and weighing when direct mass is required. For a level-derived mass, maintain a vessel strapping table and density by ingredient and condition. Flour aeration, sugar compaction and oil temperature can change the conversion.

Reconcile receipts, batches and closing stock at defined stable times. Preserve raw level, selected density and calculated inventory. Unexpected loss may indicate buildup, leakage, transfer to the wrong destination or incorrect lot records. Do not adjust conversion constants merely to force every daily balance to zero.

Batch design for major and minor ingredients

Specify absolute tolerance for the smallest addition and every batch size. A scale sized for a large major ingredient may not resolve a flavour, vitamin or processing aid. Use a dedicated minor scale, loss-in-weight feeder or preblend when needed. Validate cut-off compensation with real material because flow changes with moisture and head pressure.

Interlock discharge gates and confirm stability before accepting weight. Record target, actual addition, tolerance, lot and any manual correction. Prevent unauthorized recipe or calibration changes. If a batch is outside tolerance, apply a predefined hold, correction or rejection workflow and retain the original result.

Allergen and lot traceability

Link supplier lot, storage location, route, scale, recipe version, batch and finished product. Verify destination valves before transfer and record their feedback. During changeover, track purge or cleaning completion and release status. The system should block an incompatible material path rather than relying only on an operator note.

Design identifiers and clocks so records from PLC, weighing controller and production system can be reconciled. Define offline operation and recovery. Duplicate or missing batch numbers must raise an exception. Audit trails should show who changed recipes, limits or lot assignments and why.

Hygienic commissioning and verification

Inspect fabrication, seals and installation before product introduction. Verify cleanability using the planned procedure and inspect critical surfaces afterward. Confirm that washdown, detergent, temperature and pressure do not enter enclosures or damage seals. Where validation is required, define acceptance evidence before testing.

Run representative ingredients covering dust, poor flow, smallest dose and highest rate. Test level, overfill protection, weighing repeatability, route interlocks and data records. Simulate sensor failure, wrong material and incomplete cleaning status. Retain signed results and approved settings.

Ongoing control

Trend batch deviation, feeder time, scale zero, inventory reconciliation and cleaning findings. Review complaints or yield loss against these records. Revalidate after ingredient, supplier, cleaning chemistry, feeder, software or vessel changes. Use risk-based inspection, with shorter intervals for sticky, allergenic or microbiologically sensitive duties.

Retain evidence.

Engineering note: Food-contact, hygienic, allergen, combustible-dust and legal-metrology requirements must be confirmed for the actual product, market and plant using model-specific evidence.