## 4 Discussion
0.79 after 3 months of storage (Figure 2). Even though aw was in the range considered safe, the growth of some pathogens (Table 2) suggests that further action is needed to protect the product fully for example the addition of ingredients that have strong antimicrobial activity. Another possibility is the application selected thermal processes. Biogenic amines (BAs) are naturally occurring ingredients in food products and influence the sensory properties of foodstuffs. In low concentrations, they do not pose a threat to health, and their increased content may be the result of the activity of endogenous enzymes contained in raw materials used for food production or microbial decarboxylation of amino acids taking place [36]. The toxic effects of BAs depend on individual sensitivity, lifestyle and diet, including consumption of ethanol, as well as on the kind of biogenic amine and its concentration in food. BAs such as histamine, tyramine, cadaverine, putrescine and spermidine or spermine are involved in several pathogenic syndromes, representing a risk for consumer health [36; 37; 38]. The study bars with increased protein content we analysed to assess the potential presence of biogenic amines as a significant threat to human health. The content of biogenic amines in the study bars did not indicate high levels of these compounds. In food, the presence of biogenic amines such as histamine and tyramine is a public health concern, since these are the most notorious foodborne toxins [38]. The toxic concentration of tyramine, a biogenic amine also found in fruit, especially prunes, is 100-800 mg/kg. The values in the study bars did not exceed this range. In the case of histamine, the maximum concentration of this compound in food products should not exceed 200 mg/kg of the product [39]. In the investigated bars, this amount did not exceed 1 mg/kg of the product. It should be noted that very low amounts of histamine and tyramine, considered to be one of the most toxic biogenic amines, were found in the tested products. Despite the toxic influence of biogenic amines on food quality and human health, there is no specific regulation regarding BA content in food, except for the European Food Safety Authority, which developed a qualitative risk assessment concerning biogenic amine presence in fermented foods and concentrations that can induce adverse effects in consumers [40]. In out study of non-fermented, organic high-protein bars, no high concentration of biogenic amines was found that would pose a risk of food poisoning. Fat oxidation is one of the significant problems in the production and storage of food products, as oxidative rancidity causes quality deterioration, loss of nutritional value, and the formation of toxic compounds. Factors that accelerate these changes include oxygen, light, and high temperatures. Based on the results of the research, it was found that the applied storage conditions of the bars under refrigerated conditions (4 \({}^{\circ}\)C) had an inhibitory effect on lipid oxidative changes, as evidenced by the results of the TBARS index (Table 5). The TBARS values of bars stored at 4 \({}^{\circ}\)C were lower than the rancidity period (1-2 mg MDA/kg sample) for food products and proved their good physicochemical quality [41]. The use of prune and oat flakes in B2 bars had a significant (_p_ < 0.05) effect on the inhibition of oxidative changes in fat. The protective effect of prunes and oat flakes was particularly evident in bars stored at 22 \({}^{\circ}\)C. The antioxidant properties of prunes and oat flakes were also confirmed in their research by [PERSON] et al. [42], and [PERSON] et al. [43]. According to the values of TBARS, it can be concluded that the use of prunes and oat flakes (B2 bar composition) in the production of organic bars and refrigerated storage reduces the degree of fat oxidation.