## 3 Results and Discussion
### Assessment of Sublethal Injury
(2018) and [PERSON] et al. [PERSON] et al. (2018) is an example of this situation. In the aforementioned studies, free GE resulted in growth reductions ranging from 1.5 to 3.0 log. According to the findings of the current study, this growth reduction would probably not involve a significant amount of SI. In GSE-MIC, SI of _L. monocytogenes_ was higher than in the control and in GE-MIC. As evidenced by the SI peak in Figure 2, SI in GSE-MIC was especially relevant during the exponential growth phase of the cells. This phenomenon could result in food safety risks when low GSE concentrations are used during extended food storage at a low temperature (i.e., causing the cells to be in their exponential growth phase for a rather long period), as there might be a significant number of sublethally injured cells present which could not be enumerated on selective media. For example, [PERSON] et al. [PERSON] et al. (2018) reported that the growth of _L. monocytogenes_ was reduced by approximately 1.5 log when GSE-impregnated chitosan films were applied to mortadella-type sausages which were stored at 4 \({}^{\circ}\)C for 21 days. As another example, [PERSON] et al. [PERSON] et al. (2018) reported _L. monocytogenes_ growth reductions ranging from 1 to 2 log in hotdog model systems in which preservatives were replaced by green tea extract and GSE. Since the growth-inhibiting effect in the two aforementioned studies was only quantified by means of viable plate counts on a selective medium, the presence of sublethally injured cells was not taken into account, possibly resulting in an overestimation of these growth-inhibiting effects. TICC in pure GSE and pure GE was significantly higher than in the control, GSE-MIC and GE-MIC. This observation indicates that higher concentrations of the bioactive compounds also resulted in an increased SI. This phenomenon can introduce a possible overestimation of the antilsterial potential of both extracts in food applications at higher extract concentrations. Even though these high concentrations of natural extracts have limited applications in food industry due to the drastic effect on taste and odor of food products, a general trend in which an antimicrobial treatment that causes a more evident and acute inactivation also causes a higher SI is illustrated. In addition, the inactivation of _L. monocytogenes_ caused by the pure extracts in the current study could be comparable to _L. monocytogenes_ inactivation caused by novel applications involving lower extract concentrations. For pure GSE, the largest amount of SI was observed, implying a risk of overestimating the efficacy of novel antilsterial applications involving GSE. This risk is rather small when high GSE concentrations are used, as evidenced by the log reduction of approximately 5 log after 1 h treatment time which was observed in Figure 1C, implying that the surviving population of (injured) cells would be limited. Nevertheless, the high degree of SI could be more relevant when using lower extract concentrations which result in a less severe bactericidal (i.e., inactivation) effect. In this regard, [PERSON] et al. [PERSON] et al. (2018) investigated the potential of GSE-based aqueous media as a produce wash, reporting log reductions ranging from 2.0 to 3.6. In the study of [PERSON] and [PERSON] [PERSON] and [PERSON] (2018), Chitosan-gelatin films incorporated with GSE and _Ziziphora climopodoides_ essential oil applied to minced trout fillet resulted in _L. monocytogenes_ log reductions of approximately 1 log. Similar log reductions were reported by [PERSON] et al. [PERSON] et al. (2018) for the use of GSE and Zataria multiflora Boiss essential oil in raw buffalo patty. [PERSON] et al. [PERSON] et al. (2018) reported _L. monocytogenes_ log reductions of up to 4 log when whey protein isolate coating \begin{table}
\begin{tabular}{c c} \hline
**Treatment Condition** & **TICC [–]** \\ \hline Control & 7.8 \\ GSE-MIC & 15.1 \\ GE-MIC & 5.4 \\ Pure GSE & 98.3 \\ Pure GE & 59.3 \\ \hline \end{tabular}
\end{table}