Food Packaging Seal Checks NZ: Build a Useful Line Record and Failure Response

Food packaging seal checks in NZ need to connect an observation on the packing line with a clear product decision. A tick beside “seal OK” is hard to use if the record does not identify the pack, sealing position, check method or stock affected when something fails.

This guide is for teams checking heat-sealed pouches or lidded trays in an established food-packing operation. It helps organise a routine checking and escalation procedure. It does not set machine limits, qualify a new packaging system or provide a retort, can-seaming or aseptic-processing specification.

Food packaging seal checks: define the question

Specify whether you are checking the appearance of a formed seal, a leak pathway, a strength requirement or another defined characteristic. Do not use one result to answer every packaging question. The food-contact packaging evidence guide covers material suitability; the vacuum packaging and MAP guide addresses the decision to change packaging systems.

For Food Act operations, regulations 25 and 70 of the Food Regulations 2015 address food-related accessories under food control plans and national programmes respectively. They require accessories to support food safety and suitability to the extent of their intended use, without creating or contributing to hazards. The requirements applying to an animal-products or wine operation need to be checked under its own pathway.

Begin with the exact food, packaging codes and revisions, sealing equipment and intended storage and distribution. Identify who owns the approved specification. If those basics are unresolved, a routine tick sheet cannot establish that the proposed system is suitable.

Agree the method, criteria and sampling points

Have the packaging and equipment suppliers, with competent technical support where needed, explain how the approved process and checks fit together. Keep the set-up instructions, operating limits and acceptance criteria available to the people doing the work. A generic equipment setting or another product’s result is not a specification for yours.

The Canadian Food Inspection Agency’s flexible retort pouch defects manual describes seal problems including contamination, wrinkles, incomplete bonding and damage during processing or handling. It also explains that seal quality depends on material compatibility, temperature, pressure, dwell time and sealing-surface condition. Its retort-pouch criteria and example frequencies are Canadian, application-specific guidance; they are not universal New Zealand limits for trays and pouches.

Visual inspection, seal-strength testing and leak testing address different features. Equipment manufacturer AMETEK MOCON’s test-method overview distinguishes assessments for leaks and resistance to internal pressure, and stresses correct implementation. Ask which method, current edition, equipment and sample preparation suit the pack, what defects it can detect, and what its limitations are. Do not improvise a dye, pressure or peel test from a method name.

Write the agreed sampling locations and timing into the procedure. Consider each sealing position or lane and relevant events such as start-up, a material change, maintenance or adjustment. Also consider later handling that could damage an initially acceptable pack. The actual frequency, sample size and response belong in the product-specific plan; this article does not prescribe them.

Make the line record traceable

We recommend a record that allows a reviewer to reconstruct what was checked and what happened next. Use the following fields as a design worksheet, rather than a prescribed legal form. Record actual observations and measurements; keep a clear distinction between the expected limit and the result.

On a small screen, swipe sideways to view all columns. Keyboard users can focus the table region to scroll horizontally.

Respond to a failed check without losing the stock history

The following is a practical escalation sequence to adapt to the business’s approved procedure. A failed sample does not, by itself, define the full extent of affected production or the correct disposition.

1. Control the operation and stock. Follow the stop/escalation procedure, identify potentially affected production and prevent unintended dispatch or use. Preserve appropriate product conditions while it is held.
2. Record the evidence before changing the set-up. Identify the sample, time, defect, materials and line position. Keep photographs, samples and relevant machine or inspection records under suitable controls.
3. Establish the investigation boundary. Review earlier checks, changes, other positions and downstream handling. Do not assume the last passing sample proves that every intervening unit passed. Document uncertainty and expand the assessment where needed.
4. Correct and assess restart. Have authorised staff investigate and correct the cause, then complete the defined checks before resuming. Record what changed and why the restart criteria are met.
5. Decide the earlier stock’s disposition separately. An authorised reviewer determines whether further assessment, controlled rework, disposal or another action is appropriate. A subsequent good sample does not retrospectively clear held stock. If affected food has left control, promptly follow the applicable incident and recall-assessment procedure and seek appropriate advice.

For example, a wrinkle found after a film change should lead to an identifiable investigation interval and stock decision. Writing only “settings adjusted—OK” leaves the earlier packs unresolved. This is an illustrative record problem, not a real client finding or permission to re-seal any particular food.

Check the procedure before putting the form into use

• Can staff find the approved pack, method and acceptance criteria?
• Are sample timing, positions and event-triggered checks clearly defined?
• Are people trained in the actual method and authorised escalation route?
• Can results be linked to the affected production interval and stock location?
• Are test equipment suitability and any required checks or calibration addressed?
• Are restart and held-stock release decisions assigned to named roles?
• Will recurring defects, complaints and material or process changes trigger review?

Avoid copying a supplier’s demonstration frequency without review, recording only a pass tick, or treating stronger seals as automatically better. Keep intact-pack performance, food-contact suitability and shelf-life evidence connected but separately assessed. The broader food-testing planning guide explains why the question and interpretation should be agreed before ordering analysis.

Frequently asked questions

Prepare a focused AFVA enquiry

Send the current product and pack specification, sealing procedure, check method and criteria, a completed record, defect information and the decision still unresolved. AFVA’s new food product development support includes packaging and storage review. Consulting can help organise procedures and evidence; specialist method validation and physical testing should be scoped with the appropriate technical provider.

Consulting does not replace registration, recognised evaluation, verification or certification. Where those services apply, recognition, scope and independence requirements need to be met. No official approval or successful outcome is promised.

Sources and currency

Reviewed 1 November 2026. The Food Regulations 2015 provides the Food Act accessory duties. The CFIA retort pouch manual is a bounded technical reference for seal defects and influences; Canadian criteria are not adopted here as New Zealand requirements. AMETEK MOCON’s technical overview identifies different assessment categories; it is a manufacturer’s explanation, not a complete test method, a current-edition specification or New Zealand law.

General information only: Suitable controls depend on the actual food, process, pack, equipment, intended use and applicable business requirements. This article is not a sealing specification, sampling plan, shelf-life validation or authorisation to release food. Use current official requirements and competent product-specific advice.