By Erica Pounds

1. Customer complaint

2. Systems for identifying nature and source of

taint

3. Isolate product batch codes

4. Use both sensory and chemical analysis to

identify taint

5. Store both suspect and control samples under

suitable conditions for future testing

6. Carry out sensory testing according to ISO

standards and use many assessors

7. Have double blind tests, send out to a third

party

8. Ensure names of panelists are held for litigation

Taste – Sensory assessment of a food product in the mouth

Flavor – Complex set of olfactory, gustatory, and trigeminal sensations

perceived during the course of the tasting

Taint – an atypical odour or taste resulting from internal deterioration in

the food

Off-flavor – an atypical odor or taste caused by contamination by a

chemical foreign to the food

Detection Threshold – the lowest physical intensity at which a stimulus is

perceptible

Recognition Threshed – the lowest physical intensity at which a stimulus is

correctly identified

Food

Protein

Microbial

Taint

Carbohydrate

Fungi

Taint

Lipid

Oxidation

Off-Flavor

Raw Products

Shipping

Manufacture

Cleaning

“Up to 30% of food taint

complaints are

associated with

cleaning and

disinfecting materials”

“Until phenol-based wood preserves are discontinued,

they will continue to be one of the most common,

costly and easily preventable packaging-related causes

of taint, and wood pallets will remain high risk

contaminating surface for packaging materials.”

Compound Source Off-Flavor Notes

Chloroform Disinfectants/Solvent Sweet/rubber

cement

Potential carcinogen

Phenols Disinfectants/

Packaging

Antiseptic lotion Chloro-Phenol, Bromo-Phenol, Iodo-

Phenol, Chlorocresol

Geosmin Water Earthy

Guaiacol Paper packaging Smoky

Toluene/Xylene Ink solvent Petroleum

Sterates/Oleates Slip agents Rancid odor/soapy

tastes

Pentane 2,4-dione Adhesion Promoter Antiseptic

Aliphatic acids Recycled paper/

Degraded lubricant

Butyric/acrid

Anisoles Paper packaging Musty odors Trimethylanisole (Rubber seals)

Hexanal Plastic packaging(PE) Board/Mown grass

Compound Taste/Odor Origin

Geosmin earthy or grassy odors Produced by actinomycetes, blue-green algae, and green

algae.

2-Methylisoborneol (MIB) musty odor Produced by actinomycetes and blue-green algae.

2t, 4c, 7c-decatrienal fishy odor Produced by blue-green algae.

Chlorine bleach, chlorinous, or

medicinal taste and odor

Addition of chlorine as a disinfectant.

Aldehydes fruity odor Ozonation of water for disinfection.

Phenols and Chlorophenols pharmaceutical or

medicinal taste

Phenols usually originate in industrial

waste. Chlorophenols are formed when phenols react

with disinfecting chlorine.

Iron rusty or metallic taste Minerals in the ground.

Manganese rusty or metallic taste Minerals in the ground.

Hydrogen sulfide rotten egg odor Produced by anaerobic microorganisms in surface water

or by sulfates in the ground.

Methane gas garlic taste Decomposition of organic matter.

1. Difference Test

Panel taste test and odor test of product

2. Quantitative Descriptive Analysis

Panel uses known descriptors and an

established scale to give a flavor profile.

3. Quantitative Instrument Test

Use MS, Dynamic/Static Headspace

Technique for Odors, or Volatile Extraction

Method (twister, distillation..)

4. Verify

Verify identification by running a pure

standard and comparing retention times on

MS

Analytical Test Hedonic Test

Recruit No training

Screen Large sample size

(>100 testers)

Train

Monitor

• Number of test subjects (Unknown taint

should have a minimum of 15 panelists)

• Degree of experience of test subjects

(if taint is known, use test subjects

sensitive to taint)

• Refrain from smoking or coffee 1 hr

prior to test

• Mid-morning/mid-afternoon tests

• Comfortable temperature, relative

humidity, with limited airflow

• Odor free room (air filters with activated

carbon filter)

• Cleaning agents should not leave odors

• Sound should be restricted (sound-

resistant room)

• Lighting may partially mask the test

sample so that tests can be done only on

flavor

• Lighting shall be uniform

• Surfaces should be non-absorbent

• Wall colors should be off-white or a light-

neutral grey

• Booths shall be painted matt gray with

15% luminance factor

• Booths/work stations should be a

minimum of 3” x 2” with a divider of 1”

Test Room

Group Work Area

Volatile

• Vacuum Distillation

• Likens-Nickerson Distillation

• Kurderna-Danish evaporation apparatus

Very Volatile

• Dynamic Headspace

• Static Headspace

• Closed Loop Stripping Apparatus (CLSA)

• Solid Phase Microextraction (SPME)

• Stir-Bar Sorptive Extraction (SBSE) – twister 50-300 uses

Large Polar

• HPLC

1. Proper cleaning and disinfection of equipment (confirm with sensory

panel and with instrument testing)

a) Clean mixing equipment with a dishwasher and sanitizer

b) Use different “flavor jugs” when decanting from a 5 gallon flavor

to prevent cross contamination between batches

c) Clean pumping jugs/pumpers between batches

d) Mixing room should not use paper towels and should be odor

neutral

2. Plastic packaging certified for food use, tested to ensure compliance

with US or European law

3. New packaging or change in packaging should be checked with a trial

production run and a panel test

4. Prevent oxidation by storing product in a good container at low

temperature. Anti-oxidants are the favored method of improving

storage times and reducing rancid off-flavors

5. Setup a sensory testing area and train panelists

• http://water.me.vccs.edu/

• Taints and Off-Flavours in food Edited by Brian Baigrie

• ISO 6658 Sensory Analysis – Methodology – General Guidance

• ISO 8589 Sensory Analysis – General Guidance for the Design of Test Rooms

• ISO 8586 Sensory Analysis – General Guidelines for the Selection, Training, and

Monitoring of Selected Assessors and Expert Sensory Assessors

• ISO 10399 Sensory Analysis – Methodology – Duo-trio Test

• ISO 13302 Sensory Analysis – Methods for assessing modifications to the flavor of

foodstuffs due to packaging