Science & Research

Volume IV - 8.4 Training

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Orientation and Training
Food and Drug Administration

Section 8 - Sensory Analysis

A. Introduction to Products

FDA seafood sensory analysts are evaluated for their ability to make correct regulatory decisions in five categories of seafood products. These include:

  • Fresh/frozen Shrimp
  • Fresh/frozen raw Finfish (other than scombrotoxic-forming species)
  • Fresh/frozen raw scombrotoxic-forming species
  • Canned Tuna
  • Processed Seafood (other than canned tuna)
  1. Shrimp

    Raw shrimp is considered to be one of the easiest products for new analysts to learn to differentiate decomposition odors from the natural odors associated with the product. Other raw invertebrates are not difficult if the analyst is exposed to these products that may have unique odors. This is not to be confused with processed products, such as canned or cooked and peeled shrimp, that are considered much more difficult to assess because some of the odors have been driven off by processes such as cooking. Processed seafood may also have various additives that could confuse the inexperienced analyst.

  2. Finfish

    The second product category is fresh/frozen raw finfish. Product forms of the fish vary from whole (in-the-round), headed and gutted, steaks, fillets to chunks. Again, this category may be fairly easy for a training sensory analyst to learn to decipher odors and make good regulatory assessments as to the decomposed state of the fish.

  3. Scombrotoxic Species

    The third category includes finfish species such as tuna, mahi mahi, mackerel, escolar, etc. These fish are differentiated from other finfish because of unique spoilage patterns that may occur, especially with high temperature abuse, that may not produce much odor or have the typical “spoilage” odors that one may associate with time/temperature abuse. These odors are much more difficult to recognize and may call for many years of experience examining fish to become proficient at making good decisions.

  4. Canned Tuna

    The fourth category is canned tuna. Again, proficiency in this category tends to be more difficult due to the packing of various species, each having a unique odor, as well as the addition of various ingredients and additives. Processors use a wide variety of vegetable broths of different concentrations and various sources of hydrolyzed proteins that impart odors that could be confused with decomposition odors. Further, scorching from the retorting operation could also be confused with decomposition odors.

  5. Other Processed Seafood

    The last category is all other types of processed seafood that includes products such as cooked or canned seafood, smoked fish, pickled fish, dried fish, fish sauces and pastes, fish treated with chemicals or additives other than sulfites or phosphates, etc. Because of the lack of daily or weekly exposure to these products, many analysts do not gain enough experience to be able to recognize spoilage odors in these products. Inexperienced analysts could incorrectly associate spoilage with the odors and flavors of some of the ingredients added to such products.

B. Exercises

If possible, examples of all five product categories should be used to provide the trainee with a wide range of products to be able to assess their quality using the sessions provided below. The instructor should have significant experience in all five categories as a journeyman sensory analyst. Authentic sample packs should be prepared by the National Experts and sent out to provide consistency in the standard to be applied within the product examples to be covered during the training sessions. This will allow for minimum variability within the sample packs.

  1. Demonstration Session

    This exercise is designed to provide a complete range of product samples from each of the categories listed above from very fresh to very decomposed and to show the cut-off point between acceptable and unacceptable product.


    The analyst will examine a set of samples arranged in order from the least to the most spoiled. Sample quality will be rated on a 10-centimeter unstructured line scale (see 8.6 Appendix: Sensory Scale). For all samples examined, the trainee will indicate his/her opinion by placing a vertical mark on the 10-centimeter line. If the sample is the very highest quality possible (extremely fresh), the vertical line is placed at the very left end of the 10-centimeter line. If the quality is the lowest possible (extremely decomposed), the vertical line is placed at the very right end of the line. Positions from the extreme left end of the line to the mid-point indicate the sample passes for decomposition whereas those to the right of the mid-point indicate the sample fails for decomposition. As the position of the mark moves from the left to the right of the line, the quality of the sample declines. The vertical line dividing the line scale in half demarcates pass from fail and is not used.


    The discussion of each set of samples will take place immediately with the instructor to examine the analyst’s results and establish which degree of spoilage defined the accept/reject level for each type of product examined. The analyst also is to be familiar with the sensory terms listed above to be able to describe their findings and the reason for their decisions.

  2. Blind Discussion Session

    This session consists of having the analyst, along with the instructor, examine a random set of samples that represent the same product examined during the demonstration session. The purpose of this exercise is to determine if the analyst can apply the criteria that was used to determine accept/reject levels and to reinforce the decisions made on the demonstration samples.

  3. Practice Test Session

    The purpose of this session is to collect data on the assessments made by the analyst using blind coded samples and to allow the trainee to practice what they have learned during the demonstration and blind discussion sessions. Results are discussed and the analyst will be allowed to go back and look at the samples.

  4. Final Test Session

    The purpose of this session is to assess the analyst’s retention of the sensory training for each product type examined. The analyst is to assess the blind coded samples without the presentation of the standard reference samples beforehand.

C. Questions

  1. What section of the FD&C Act talks about adulteration of seafood products by decomposition?
  2. What are the four basic tastes?
  3. What are the five seafood product categories that the sensory analyst is provided training to make classifications on the quality in seafood products?
  4. Explain how the 10 centimeter unstructured line scale is used.

Page Last Updated: 03/18/2016
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