# Changes in Quality Features of Pork Burgers Prepared with Chokeberry Pomace During Storage
## 3 Results and Discussion
### Microbiological Quality of Pork Burgers During Storage
The available literature provides no information on the direct application of unprocessed chokeberry pomace in meat products. However, research has focused on using dried fruit or vegetable pomace and extracts derived from pomace [14; 15; 17; 45]. Black chokeberry fruits and their by-products, such as pomace, are rich in polyphen compounds, with anthocyanins being the dominant group [20; 24]. These compounds are known for their antioxidant and antimicrobial properties [22]. According to [PERSON] et al. [12], the antimicrobial effect of pomace is believed to result from both the presence of many bioactive compounds and the low pH value. Minced meat products, such as burgers stored at refrigerated temperatures, provide an ideal environment for microbial growth, leading to quality deterioration and reduced shelf life. While no legal limit exists for the maximum number of aerobic mesophilic bacteria in meat products, it is generally accepted that they become unfit for consumption when bacterial counts reach 7-8 log cfu/g [52]. Additionally, LAB, _Pseudomonas_, _Enterobacteriaceae_, and _B. thermosphacta_ can proliferate under refrigerated conditions [51; 53; 54]. [PERSON] et al. [14] investigated the antibacterial properties of water extracts from various fruit pomaces, including black chokeberry, blackberry, red currant, and blueberry (60 g/800 g of meat batter), as potential ingredients in minced beef patties stored under refrigeration for 9 days. On the first day after production, the total number of aerobic mesophilic bacteria was significantly (\(p<0.05\)) lower in products containing extracts from chokeberry, blackberry, and blueberry pomace compared to the control. This trend persisted until day 6 of storage. The observed reduction in the antibacterial activity of berry pomace extracts was attributed to the gradual degradation of bioactive compounds, including polyphenols. A similar decline in antibacterial activity was observed for psychotrophic bacteria, LAB, and _Staphylococcus_ bacteria. Unlike in the present study, [PERSON] et al. [14] found that none of the berry pomace extracts significantly inhibited LAB growth during beef patty storage. However, the authors concluded that water extract from black chokeberry pomace was the most promising natural preservative among the tested berry pomace extracts. [PERSON] et al. [45] evaluated the effects of different concentrations of water and ethanol extracts from defatted chokeberry pomace on the growth of selected pathogenic and spoilage bacteria. Based on results obtained from pork slurries, ethanol extract from chokeberry pomace was selected for further testing in pork meat products. One of these products was minced meat burgers, which, according to the authors, provide a particularly favorable environment for microbial growth due to significant cell damage, high free water content, and suitable pH. Spoilage of such refrigerated meat products is largely attributed to the growth of _B. thermosphacta_, LAB, _Pseudomonas_ spp., and _Enterobacteriaceae_. While heat treatment can stabilize the microbiological quality of burgers, it may also weaken the antimicrobial properties of plant extracts due to the degradation of temperature-sensitive bioactive compounds. It was found that adding 2% ethanol extract from chokeberry pomace inhibited the growth of _B. thermosphacta_ in pork burgers during 16 days of refrigerated storage. In samples without extract, _B. thermosphacta_ counts increased to 7 log cfu/g, while in samples containing the extract, bacterial counts remained significantly lower at 3.87 log cfu/g. Additionally, chokeberry pomace extract effectively inhibited the growth of aerobic mesophilic bacteria, _Pseudomonas putida_, and LAB during storage. On day 16, the number of these microorganisms in burgers with the extract was significantly lower than in the control product. [PERSON] et al.