**3. Materials and methods**

#### **3.1 Panels and panelists**

The study at hand compares results from two sensory olive oil panels, namely the German Olive Oil Panel/DOP and the Swiss Olive Oil Panel/SOP.

Both panels are objective expert panels whose members have many years of experience in the sensory evaluation of olive oil. Specific infrastructure makes it possible to either carry out sensory tests synchronously and "*in situ*" in sensory laboratory (or comparable) situations, equipped with test booth, heaters, etc. On the other hand, both panels have the possibility to test asynchronously at so-called home testing stations. All panelists from both panels are regularly trained and undergo permanent monitoring of their panelist and panel performance. Additionally, both panels take part in regular inter-laboratory comparisons (proficiency tests). This is—in addition to other requirements—an important basis for their consistent, reliable, and successful work. Engaged in research projects as well as services, both panels contribute to the continuous development of quality on the olive oil market.

#### *3.1.1 Swiss olive oil panel (SOP)*

The SOP consists overall of 38 panelists and was founded in 2002. Since 2006 the SOP is accredited in accordance with EN ISO/IEC 17025 [5] and has been recognized by the International Olive Council (IOC) between 2009 and 2021. In the study at hand, the same nine panelists contributed "*in situ*" and synchronously to a test in a sensory laboratory situation as well as "remote" and asynchronously at their home testing stations.

#### *3.1.2 German olive oil panel (DOP)*

The DOP consists overall of 25 panelists and was founded in 1999. Since 2012 the DOP is accredited in accordance with EN ISO/IEC 17025 [5] and has been recognized by the International Olive Council (IOC) between 2012 and 2021. In the study at hand, the same 11 panelists contributed "*in situ*" and synchronously to a test in a sensory laboratory situation and "remote" and asynchronously at their home testing stations.

### **3.2 Test situations**

There are at least two options to conduct sensory tests—on the one hand "*in situ*" the more common version of central location tests (CLT) in standardized testing rooms, for example, sensory laboratories, where panelists work synchronously and on the other hand "remote" the—at least in sensory analysis—less common home tests (HT) at so-called home testing stations, meaning in panelists homes, where panelists work in personal, but nevertheless standardized workspaces. Thinking about the advantages and disadvantages of the named test situations, we find pros and cons for both sides.

### *3.2.1 Sensory laboratories (*in situ*)*

The sensory laboratory of SOP is located on the ZHAW campus in Wädenswil. It consists of 12 separate test booths. Each booth is equipped with a computer (incl. data acquisition software FIZZ by Biosystemes) and a heating device by Ettore Pasquali (mod. 145). Each heating device is recorded in a device list of the QMS and is checked regularly. Detailed information concerning the procedure of testing in the sensory laboratory (and concerning additional equipment, such as test glasses, spittoons, and palate-cleansing agents) is described in the QMS (internal document: Standard Operation Procedure: LMT-SEN-A5-302\_translated EN → Sensory Evaluation at ZHAW (Sensory Laboratory)).

The sensory laboratory of DOP is in Nuremberg, Maxfeldstrasse 50. It consists of 12 separate mobile test booths. Each booth is equipped with a computer (incl. data acquisition software SENSORY by IMEDIA) and a heating device by Ettore Pasquali (mod. 145). Each heating device is recorded in a device list of the QMS and is checked regularly. Detailed information can be found in the QMS (internal document: Standard Operation Procedure SOP 07-02-02).

On the "Pro" side (**Table 1**) there is of course a high level of standardization. Samples are prepared in an absolute neutral way by the panel leader (or a technician), the testing takes place synchronously (at the same time) and electronic equipment is used for data collection and analysis.

On the "Contra" side (**Table 1**) we see low flexibility in terms of scheduling tests, especially because panelists must be available at the same time. If panelists are not collaborators and work on-site, they must travel. This is time- (and cost-) consuming.


#### **Table 1.**

*Pros/cons of a test situation in a sensory laboratory.*

*Sensory Evaluation of EVOO: Do Different Test Locations Have a Relevant Impact on Data… DOI: http://dx.doi.org/10.5772/intechopen.102702*

Moreover, even in a sensory lab, there is potential for additional interruptions (noise, malfunction, or else) with negative effects.

#### *3.2.2 Home testing stations (remote)*

Within the SOP, each panelist has set up a personal testing station in a room in his or her home. Each testing station is equipped with a heating device (Rosenstein & Söhne), a thermometer (Testo Mini penetration thermometer), and blue glasses including cover glasses. Each heating device and the thermometer is recorded in a device list of the QMS and is checked regularly. Detailed information concerning the procedure of testing in a home testing station is described in the QMS (internal document: Standard Operation Procedure: LMT-SEN-A5-303\_translated EN → Sensory Evaluation at Home Testing Stations).

Within the DOP each panelist has set up a personal testing station in a room in his or her home, which meets the test conditions of the IOC in terms of light, temperature, noise, and odors (COI/T.20/DOC. No 6/Rev. 1). The mobile booth is made up of folding elements in such a way that the panelist is isolated from negative ambient conditions. Each test station is equipped with a heating device (Ettore Pasquali, mod. 145), a thermometer (Testo Mini penetration thermometer), and blue glasses, including a cover glass. Each heating device and the thermometer is recorded in a device list of the QMS and is checked regularly. Detailed information can be found in the QMS (internal document: Standard Operation Procedure SOP 07-02-02).

On the "Pro" side (**Table 2**) there is—like for a lab situation—as well a high level of standardization because as well home testing stations provide ISO accreditation. Asynchronous testing increases flexibility for scheduling tests, meaning that testers do not have to be available at the same time, only in a defined period. Less traveling time and costs are positive and of course—like in the lab situation—as well at home testing stations, electronic equipment for data collection and analysis is used.

On the "Contra" side (**Table 2**), we see that a sample dispatch is needed, which must be well organized regarding packaging and preparation of samples. For temperature protection during transport, Styrofoam boxes are used, and the oil is coded


#### **Table 2.**

*Pros/cons of a test situation at a home testing station.*

and bottled to dark 30 ml bottles. Sample preparation, directly before testing, is done by the panelist. He or she must pour out exactly half of the bottle (15 from 30 ml). Asynchronous testing is of course different compared to asynchronous lab testing situation, but since panelists are well trained on using the methodology and it is always (as well in the lab) a single panelist evaluation before compiling data, this does not lead to any problems. Finally, and again like in the lab situation, there is of course potential for additional interruptions (noise, malfunction, or else).
