SIST EN ISO 10399:2018 PDF

Overview

EN ISO 10399:2018 / ISO 10399:2017 - Sensory analysis - Methodology - Duo‑trio test - is a CEN‑adopted international standard that specifies a controlled, forced‑choice procedure for determining whether a perceptible sensory difference or similarity exists between two products. The duo‑trio test is applicable when differences may occur in one or several sensory attributes and is especially useful when the nature of the difference is unknown. It is statistically less efficient than the triangle test (ISO 4120) but is easier for assessors to perform.

Key topics and requirements

• Test principle: Assessors receive a triad - one sample labelled as the reference and two coded samples. One coded sample matches the reference; the assessor must indicate which coded sample is the same (or different) from the reference. Correct responses are counted and significance is determined by statistical tables.
• Two formats:
  • Constant‑reference technique - use when one product is familiar (e.g., regular production).
  • Balanced‑reference technique - use when neither product is more familiar.
• Assessor selection & training:
  • Assessors should have uniform qualifications appropriate to the objective (see ISO 8586 guidance).
  • Typically 32–36 assessors are used when testing for difference, but numbers should be chosen to meet desired sensitivity.
  • Useful for selecting, training and monitoring assessors.
• Test conditions:
  • Prevent communication among assessors; use booths conforming to ISO 8589.
  • Prepare samples out of sight and present identically (same vessels, quantity, temperature).
  • Code samples randomly (preferably three‑digit numbers) and mask irrelevant appearance cues.
  • Give clear instructions (e.g., whether to swallow) and avoid disclosing product identity or expected effects during testing.
• Statistical concepts: The standard references α‑risk (Type I) and β‑risk (Type II) and defines test sensitivity in terms of these and the proportion of detectible differences.

Applications and users

EN ISO 10399 is suited for:

• Quality control and validation after changes in ingredients, processing, packaging, handling or storage.
• Product development when verifying if a production or formulation change causes perceptible differences.
• Sensory panel selection, training, and monitoring. Primary users include sensory scientists, quality assurance teams, R&D departments, and contract sensory laboratories in food and beverage industries and other product sectors where sensory properties matter. Note: the method applies only when products are fairly homogeneous.

Related standards

• ISO 4120 - Triangle test (more statistically efficient alternative)
• ISO 8589 - Test room design / sensory booths (test environment)
• ISO 5492 - Sensory analysis vocabulary (terms and definitions)
• ISO 8586 - Guidance on assessor selection and training (qualification)

Keywords: Sensory analysis, duo‑trio test, ISO 10399:2017, EN ISO 10399:2018, forced‑choice procedure, sensory difference, similarity testing, assessors, constant‑reference, balanced‑reference.