Although sensory evaluation of fish is mainly discussed here, most aspects of sensory evaluation are very general and can refer to sensory evaluation of other foods.
Environment and conditions in sensory evaluation
It is highly desirable that there are special facilities or rooms where sensory assessment in quality control takes place. In particular, the following points need to be kept in mind regarding sensory evaluation:
- The room must not contain noise and external interference from other activities. Lighting must be good and there must be no odor pollution from elsewhere.
- A separate facility, separate from the sensory assessment room, is desirable for sample preparation. At least some kind of partition needs to be created so that the assessors do not monitor the preparation of samples. There must also be a partition between the participants, but this only requires cards on the table. The room needs to be well located in the business, so that it is close for people to leave.
Preparation and implementation of sensory assessment
The fish fillets are cooked in the oven without any additives (including salt). Microwave ovens come in handy. The normal consumption temperature of food is used and care is taken to ensure that judges receive samples at that temperature. Care should be taken not to show rash.
The amount of samples is at least 2 to 3 bites per judge. Boiled samples are kept hot on hot plates in closed glass bowls. Circumstances must determine whether the judges take samples themselves or have samples dispensed to discs. It might be most cost-effective to boil all the samples first and then dispense them onto plates when the judges come to the assessment to take the shortest time and create the most privacy. It is possible to boil each piece for each judge in a small glass bowl or plastic glass (with plastic film over it) so that he can have each sample dosed in a glass and can smell from the glass and then taste. Check that the plastic can withstand microwave heating. Care must also be taken that containers and labels do not contaminate the samples (eg markers).
The number of samples that can be tasted at one time needs to be limited. Two to four samples is suitable, but it depends on the nature of the samples and the taste. Always serve water with samples and sometimes it is desirable to give something neutral between samples (eg thin crispbread, water biscuits, apples, cucumbers).
There is a certain risk of error detection. Samples are always kept secret because everyone wants to do well and can then draw conclusions on the wrong grounds. It is best to mark a sample with a two- or three-digit number. This way there is less risk of people trying to associate the number with any information. Attempts are made to balance samples and people are told in which order to evaluate the samples. Samples marked eg 43, 23 and 78 shall be presented in such a way that one judge first evaluates sample 43, another first evaluates sample 23 and the third sample 78 and then head to head. It should be borne in mind that appearance can control odor and taste evaluation and lighting is even changed if possible and deemed necessary. Also, the assessment of quality factors may shift because arbitrariness overrides actual perception.
It can affect the perception of whether people are hungry or true. It is best not to eat or smoke for one hour before sensory evaluation. The best time for sensory evaluation of cooked food is from 10 to 11 fh and 14 to 15 eh, but then people are considered the most sensitive and reasonably long at meal time. It is not advisable to use too much perfume and moisturizers as this can interfere with other participants (should not be a problem in food processing). Colds and other illnesses can impair your ability to perceive your senses. Often something tasty is present at the end of sensory evaluation.
Selection of companies' sensory assessment groups
It is advisable to train 4 to 6 judges in the sensory evaluation group, even if not all of them will be evaluated each time. The most important thing when choosing people in a company's sensory evaluation group is certain characteristics of people, such as diligence and conscientiousness, and participants need to be interested. These characteristics have probably already been revealed in other jobs. The person in question generally needs to be present at the workplace when the sensory assessment takes place and be able to attend at those times. Conditions need to be created for people to attend sensory assessments when they are expected to. The next supervisor of the employee in question must have an understanding of what is required of a sensory evaluation judge and be satisfied with it. People also need to be in good health and have a natural sensitivity (sense of taste and smell).
Training people for sensory evaluation
- Learn to recognize the taste and smell characteristics of fresh fish and evaluate based on that
- Knowledge of the nature and limitations of the senses
- Organization of sensory evaluation
The training of the sensory evaluation group shall begin by describing the organization of the sensory evaluation, what is expected, etc. It is desirable to describe the nature and limitations of the senses, such as taking a deep breath and resting between displays during odor assessment. The grade to be used in the freshness assessment must be carefully reviewed and it must be emphasized that people are not expected to judge by the person's personal taste, but to read the descriptions and follow the grade.
In the case of a practical assessment of fish, three to four samples of fish are obtained where the storage time in ice and treatment are known (eg from one fishing trip of the same trawler). The people should be informed of the age of the raw material and have the samples assessed with age in mind, and know whether the people can agree on grading for the sample in question. Then people are allowed to taste different samples and preferably the same sample three times. The samples are then encrypted. Make sure that people get to know fish at all levels, ie. not just a precautionary measure.
Try to evaluate the results of the training sensibly and summarize the mean and standard deviation of each sample. Check whether one judge stands out, is for example always higher or lower than the others in their judgments or is in some way at odds with the others. Also note how people manage to repeat themselves, ie. by repeated evaluation of the same samples. Repeat the training several times and very soon it will be seen if anyone is unfit.
Then start a regular evaluation with the team and continue to monitor the judges' performance in the same way. It should be noted that everyone does a shoot at some point and that is normal. Care should be taken to ensure that people are sufficiently interested and have not become bored or tired of sensory evaluation. Some kind of boost (reward in some form) and performance information may be needed to keep people motivated.
Skynmat - QIM
Sensory evaluation is an important part of Matís' operations and is also mainly used in quality control and product development at Icelandic food companies. For many years, Matís has assisted companies in developing sensory evaluation, provided advice in sensory evaluation and carried out shelf life research in cases where sensory evaluation is a very important factor.
Sensory evaluation has been used in various research projects, both domestic and foreign. Matís' staff has provided theoretical and practical instruction in sensory assessment at the Department of Food Science at the University of Iceland and at the fisheries department of the University of Akureyri's resources department. Matís' staff has also taught sensory assessment at the United Nations Fisheries Academy since 1998. Matís has also held various sensory assessment courses for employees of fish processing companies and other food companies.
Matís has very perfect sensory assessment facilities, with a special sensory evaluation room with separate booths, perfect lighting and ventilation. There are also good facilities for handling food and preparing samples and this is very useful for seminars and teaching.
In recent years, work has been done on the development of new sensory evaluation methods, especially for sensory evaluation of whole fish. The method that fish researchers in Europe agree will be most suitable for fresh fish food is the so-called QIM quality factor method. This method is very suitable for teaching and training and coordination of assessment and it can be mentioned that in 2003 all fish market staff in this country were trained in this method. Matís is a partner in QIM-EUROFISH which works to harmonize sensory assessment methods on fish. Finally, Matís also participates European Sensory Network which is a collaborative platform for universities, institutions and companies in Europe in the field of sensory evaluation.