Sensory Test Ii - Chapter 16

Front 1

1. In a typical food production facility a very small proportion of products are defective.
• Explain how this can produce a high rate of false alarms from sensory testing.
• Explain how you can adjust a sensory QC program to deal with the high rate of false alarms.

Back 1

You're testing a LOT of product - say 10% defective & say a, b = 0.10

Out of 100 productd:
900 good --> 810 found good 90 found defective
100 defective --> 90 found defective, 10 found good

Of all those found defective, only 50% are really defective!!

Thus, it is v wise to build in a backup system for a second check of defective ones (ie have them retested by others); ideally, you have a lower rate of false alarms

Front 2

Describe several management issues (cost / time concerns) about sensory QC programs?

Back 2

- There is a significant time/money investment to setup program: standards must be identified and cutoff/specs detailed
- Employees needed for taste panel takes away from "real job"
- level of thoroughness in sampling for comfort vs cost of overtesting
- QC should not report to management since their bottom-line goals are often at odds
- Continual investment in program

Front 3

How might one determine an allowable size of a specific sensory deviation in a product? For example how could you decide what range of raspberry flavor was allowable in a raspberry yogurt?

Back 3

Research is required.

You could setup a consumer test with samples of widely varying raspberry levels. Ask them liking or JAR.

Front 4

Why are simple difference tests (e.g. triangle or paired comparison tests) not generally suitable as sensory QC tests?

Back 4

Because differences do not necessarily equate to unacceptable & there will be some natural variation in the product

Any QC Test must be setup to handle intrinsic product variation

Front 5

What is the advantage of including a ‘blind control’ in a sample set where several production samples are compared against a control (gold standard) sample?

Back 5

- It can help to establish a baseline of responding on the scale--> provides an estimate of placebo effect

- You can also include a control from a different batch to asses product variability

Front 6

Explain how descriptive analysis applied to quality control differs from descriptive analysis applied to research and product development purposes?

Back 6

For research, the goal is to fully characterize the product

For QC, attention is usually given to a few critical attribues

Front 7

What are the strengths of using descriptive analysis for QC? What are the weaknesses?

Back 7

Strengths
1 Correlated well to other methods including instrumental
2 less cognitive load: focus on a single attribute at a time
3 Reasons for defects/ appropriate corrective actions are more obvious

Weaknesses
- Extensive training required
- Multiple judges needed
- Data analysis required
- references needed
- Problems can occur in attributes not rated