## 2 Materials and Methods
### Shelf Life Evaluation  
Quality evaluation of the chicken samples was based on microbial growth (TVC, _Pseudomonas_ spp., _Brochotltrix thermosphacta_), pH, colour, and sensory scoring.  
For the evaluation of microbial load, 10 g of chicken flesh (including the skin) was transferred to a sterile stomacher bag with a 90 mL sterilised Ringer solution (Merck, Darmstadt, Germany). Homogenisation was achieved using a Stomacher (BagMixer(r) Interscience, Saint Nom la Breteche, France) for 60 s. Samples (0.1 mL) of 10-fold serial dilutions of meat homogenates were spread on the surface of the appropriate media in Petri dishes for the enumeration of different spoilage bacteria. The microbial load was expressed as the average log CFU/g. TVC was enumerated on a plate count agar (PCA, Merck, Darmstadt, Germany) after incubation at 25 \({}^{\circ}\)C for 72 h, whereas _Pseudomonas_ spp. were enumerated on a Cetrimide agar (CFC, Merck, Darmstadt, Germany) after incubation at 25 \({}^{\circ}\)C for 48 h. _Brochotltrix thermosphacta_ was enumerated on an STAA agar (CM 881, Oxoid, Cambridge, UK) supplemented with SR 151 (Oxoid) and incubation at 25 \({}^{\circ}\)C for 48 h. Two replicates of at least three appropriate dilutions were enumerated for each sampling point and growth medium.  
Quantification of the colour of the tested samples was made using a CR-Minolta Chromatater(r) (Minolta CR-200, Osaka, Japan) with an 8 mm measuring diameter, using the CIE L*, a*, b* colour scale (CIE 1978). The instrument was standardised under the \"C\" illuminant condition according to the CIE using a standard white reference tile (calibration plate CR-200, L = 97.50, a = \(-\)0.31, b = \(-\)3.83). The overall colour change, \(\Delta\)E, was calculated by \(\Delta\)E = [(L - L\({}_{0}\))\({}^{2}\) + (a - a\({}_{0}\))\({}^{2}\) + (b - b\({}_{0}\))\({}^{2}\)]\({}^{1/2}\). Colour measurement of chicken meat was carried out at three points of five specimens.  
The pH value of the tested samples was measured in the diluted meat in Ringer's solution at a ratio of 1:10 during the shelf life experiment (pH-meter AMEL 338, Italy) (\(n\) = 3). pH measurement was implemented in the homogenized meat sample into the Ringer solution after the sampling for microbiological analysis.  
The sensory parameters of raw chicken samples were evaluated by a sensory panel of 6. The sensory panel participated in a preliminary training session, where the overall process and point scale were introduced by introducing the reference samples corresponding to different quality levels of the tested food product. Sensory evaluation was implemented on uncooked chicken thighs, considering the odour/off-odour and the visual appearance/colour. The samples were displayed to the evaluators on 3-digit coded white paper plates. The appearance and odour of chicken samples were rated using a 1-9 hedonic scale (9 = like extremely and 1 = dislike extremely). Panellists were also asked to evaluate the overall impression and acceptability. A sensory score of 5 was taken as the average scoring for minimum acceptability, indicating the end of shelf life. Scores given for the sensory attributes were mathematically modelled by apparent zero-order equations:  
\[s=s_{0}-k\cdot t,\]  
where s and s\({}_{0}\) are the sensory scores at time t and zero, respectively, and k is the apparent rate of quality deterioration based on sensory scoring (d\({}^{-1}\)).  
The overall experimental design is demonstrated in Table 1.