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Why auditors must broaden their horizons and develop sector-specific knowledge

Auditing is not merely the process of comparing documented procedures with the requirements of a standard. A capable auditor must understand the organization’s processes, products, technologies, risks and methods of control.

Sometimes this requires us to look beyond conventional measuring instruments.

Many years ago, I audited a world-class company in Yemen. The organization manufactured food items as well as household and personal-care products, including liquid detergents and soaps to which carefully selected fragrances were added.

During the audit, I encountered a fascinating example of sensory evaluation—one that changed the way I thought about monitoring and measuring resources.

Last week, I audited another company that manufactures liquid detergents, handwash, utensil degreasers and similar products. The experience reminded me of a fascinating and often overlooked aspect of quality control: situations in which a human sense organ functions as a monitoring and measuring resource.

So, I thought I would share this interesting side of “calibration”—or, more precisely, how an individual’s sensory competence is verified and monitored when product conformity depends on human judgment.

We measure with our senses

Human beings continually use their senses, knowingly or unknowingly, to evaluate the world around them.

We look at a product’s colour and appearance. We touch it to judge texture. We listen for unusual sounds. We taste food to assess flavour. We use our noses to detect freshness, spoilage and fragrance.

The nose is one of our most sensitive monitoring resources.

A trained person may smell a product and identify whether its fragrance is jasmine, lemon or another variety. The person may also detect an undesirable odour or determine whether the intended fragrance has weakened.

But identifying a fragrance is only a qualitative assessment.

The more difficult questions are:

• Is the fragrance present at the required intensity?
• Is it consistent with the approved master sample?
• Will it remain acceptable throughout the product’s stated shelf life?
• Can the assessor distinguish an acceptable batch from a marginal or nonconforming one?

If a detergent or soap has a two-year shelf life, the organization may need evidence that its fragrance remains acceptable at the end of that period—not merely when the product leaves the factory.

When product acceptance depends on a person’s sensory judgment, that judgment becomes part of the organization’s monitoring and measurement process.

What ISO 9001 requires

Clause 7.1.5 of ISO 9001:2015 requires an organization to provide suitable resources when monitoring or measurement is used to verify that products and services meet requirements. Those resources must be maintained so that they remain fit for their intended purpose.

Where measurement traceability is required or considered essential for confidence in the results, clause 7.1.5.2 requires appropriate controls. Depending on the situation, these can include calibration or verification, identification and protection against conditions that could invalidate the results.

This does not mean that a human nose is calibrated in exactly the same way as a thermometer or weighing balance.

A more technically accurate approach is to:

• validate the sensory evaluation method;
• select people with the required sensory ability;
• train and qualify the assessors;
• verify their performance against recognized reference samples;
• conduct proficiency or interlaboratory comparisons where appropriate;
• monitor their continuing competence;
• control the testing environment; and
• retain records demonstrating the validity of the results.

The important audit question is not, “Does this person have a calibration certificate for their nose?”

The better question is, “How does the organization demonstrate that this sensory assessment consistently produces valid and reliable results?”

How can sensory ability be verified?

An organization may obtain reference materials or coded samples from a competent external provider. The characteristics or concentrations of these samples are known to the provider but are not disclosed to the assessor.

The assessor evaluates the samples and submits the observations. The provider then compares the results with the assigned values or expected classifications.

If the assessor correctly identifies or ranks the samples within established acceptance criteria, the result provides evidence of sensory competence. Repeated exercises can also reveal bias, declining sensitivity or inconsistent performance.

Organizations may supplement external comparisons with:

• approved master samples;
• blind duplicate samples;
• sensitivity and recognition tests;
• threshold testing;
• periodic requalification;
• agreement studies involving several assessors; and
• statistical monitoring of individual and panel results.

In practice, we are verifying the person’s capability and the reliability of the complete sensory evaluation system—not calibrating the biological organ in a strictly metrological sense.

The person and the environment must be controlled

Sensory performance can be influenced by temporary health conditions and environmental factors.

A competent sensory programme may therefore establish controls relating to:

• colds, allergies or nasal congestion;
• smoking or exposure to tobacco smoke;
• the use of perfume, scented cosmetics or strongly fragranced products;
• recent consumption of strongly flavoured food or beverages;
• exposure to chemicals or powerful odours;
• fatigue and sensory adaptation;
• room temperature, ventilation and cleanliness; and
• the time allowed between samples.

For example, an assessor wearing a strong perfume could alter the testing environment and affect not only their own judgment but also that of the entire panel.

Competence must therefore be maintained and periodically reconfirmed. A person who demonstrated excellent sensory ability several years ago should not automatically be assumed to possess the same capability today.

A rare but valuable capability

People with exceptional fragrance sensitivity and discrimination can be difficult to find. Selecting them should be based on objective screening and performance evidence rather than assumptions about gender, age or background.

Some individuals may naturally possess remarkable sensory ability, but natural talent alone is not sufficient. Reliable product-release decisions require training, controlled methods, suitable reference samples, defined acceptance criteria and continuing performance monitoring.

The lesson for auditors

Auditors must widen their horizons.

A monitoring or measuring resource is not always a device with a display, serial number and calibration label. Depending on the sector, it may include a master colour sample, a reference material, software, an inspection jig—or a trained human assessor using sight, taste, touch, hearing or smell.

An auditor who understands only the words of the standard may overlook these controls. An auditor who understands the organization’s sector will ask how sensory judgments affect conformity, how assessors are selected and qualified, and how confidence in their results is maintained.

That is where auditing becomes more than checklist completion.

It becomes professional inquiry.