## 3 Results and Discussion
### Effects of Antimicrobials on Shelf Life
\begin{table}
\begin{tabular}{c c} \hline \hline
**Sample** & **Shelf Life** \\  & **[Day]** \\ \hline CTRL\_1 & 0.762 \(\pm\) 0.164 \({}^{\mathrm{e}}\) \\ CTRL\_2 & 1.730 \(\pm\) 0.171 \({}^{\mathrm{d,e}}\) \\ SAMP\_1 & 2.905 \(\pm\) 0.406 \({}^{\mathrm{c,d}}\) \\ SAMP\_2 & 6.584 \(\pm\) 0.225 \({}^{\mathrm{b}}\) \\ SAMP\_3 & 3.927 \(\pm\) 0.698 \({}^{\mathrm{c}}\) \\ SAMP\_4 & 9.978 \(\pm\) 0.541 \({}^{\mathrm{a}}\) \\ \hline \hline \end{tabular} Data are presented as mean \(\pm\) SD. Data in each column with different superscript letters are statistically different (\(p<0.05\)). CTRL_1 = meat sample without any treatment; CTRL_2 = meat sample treated with lactic acid; Samp_1 = meat sample treated with grape pomace powder; Samp_2 = meat sample treated with grape pomace powder and nucleic acid; Samp_3 = meat sample treated with grape pomace powder and pomergnanate extract; Samp_4 = meat sample treated with grape pomace powder, lactic acid and pomergnanate extract.  
\end{table} 
Table 6: Data of shelf life (day) calculated from the fitting procedure. value of 35.17 was obtained. The value of \(\Delta\%\_4>1\) means that also PE can exert positive effects on nuggets shelf life and it does not surprise if we consider the recognized activity of pomegranate extract on meat [44, 45]. The effect of PE on the shelf life of chicken nuggets can be also assessed by using the Samp_LA_GPP and SAMP_LA_GPP_PE samples, thus calculating a new normalized percentage difference (\(\Delta\%\_5\)). The obtained value is 51.56, which is slighter greater than \(\Delta\%\_4\). The reason for this results is that \(\Delta\%\_4\) measures the effect of PE in presence of GPP, whereas \(\Delta\%\_5\) measures the effect of PE in presence of GPP and LA [46]. The observed difference can be ascribed to the presence of LA which acted synergistically with GPP and PE to slow down the microbial quality decay of the investigated food [37]. By comparing the shelf life of the SAMP_LA_GPP_PE and CTRL samples, it is possible to measure the synergy of the three studied antimicrobial agents acting together. In this case the calculated normalized percentage difference (\(\Delta\%\_6\)) is equal to 1209.50, which is quite high. An attempt was made to evaluate whether there is a synergistic effect between the antimicrobials studied. To this aim, to calculate the normalized percentage increase it was necessary to add the shelf life increase individually obtained by using LA, PE, and GPP, and compare it with shelf life of CTRL. In particular, the CTRL and CTRL_LA samples were used to calculate the sole effect of LA, the CTRL and Samp_GPP samples to calculate the sole effect of GPP, and the Samp_LA_GPP and Samp_LA_GPP_PE samples to calculate the sole effect of PE. The above effects were added together and used to calculate the normalized percentage increase (\(\Delta\%\_7\)), the value obtained is 853.77. It is worth noting that \(\Delta\%\_7\) does not consider any synergistic effect that the antimicrobials investigated could exercise, it simply adds the effects that individual antimicrobials can have on shelf life. As reported beforehand, \(\Delta\%\_7\) is way lower than \(\Delta\%\_6\). This is not surprising, as in the literature it was reported that antimicrobials can act synergically in slowing down the microbial growth [3, 47]. Therefore, the \(\Delta\%\) values are useful to make comparisons and underline differences among samples. Further research could be carried out to better understand the mechanisms of action and the interactions between polyphenols and organic acid that justify the recorded effects in poultry meat.