## 4 Discussion
monocytogenes_ between the 0 and the 6 th day of storage in AC sausages was noted and affected the growth potential result[PERSON] These observations differ from results of [PERSON] [26], who reported a continuous increase in the _L. monocytogenes_ number during the storage of meat products manufactured without nitrite, with sodium nitrite or with nitrite from natural sources. In the present study, the difference between control and AC sausages resulted from the use of nitrites. As was pointed out by [PERSON] et al. [27], the suppression of _L. monocytogenes_ growth increases with ongoing nitrite concentration. In this study, the amount of residual nitrite in both sausages differed, but the number of _L. monocytogenes_ was similar, except for day 6 and 8. As was reported by [PERSON] et al. [27] there is no correlation between residual nitrate and nitrite concentration in meat products and _L. monocytogenes_ counts, which explains the results of this study. Nitrite added to the meat during production can react with many components in the matrix depending on the type of processed meat, the processing conditions, the presence of sodium ascorbate, and other factors (myoglobin, nonheme proteins, lipids concentration), and therefore the amounts of analytically detected nitrite or nitrate contents do not reflect the initially added preservative [22]. As shown in this study, the formulation of control sausages (nitrite and sodium chloride content) as well as the packaging and storage method was successful in obtaining products in which the growth of _L. monocytogenes_ was not supported. This shows the effectiveness of the hurdle technology used in the prevention of _L. monocytogenes_ proliferation. The hurdle technology consists of applying many physicochemical factors affecting the growth of the bacteria, i.e., lowering the pH, reducing water activity, adding salt and nitrite or nitrate, using lactic acid bacteriocins. Only the synergistic interaction of many factors brings the intended effect of the use of nitrites/nitrates; especially in ready-to-eat products. As a result of this strategy, it is possible to inhibit the growth of _L. monocytogenes_ in refrigerated conditions more effectively, increasing food safety [10; 28]. The physico-chemical factors that affected the pathogen growth were water activity, moisture and protein contents [27]. The concentration of protein and water activity in control and AC sausages used in this study was similar. Therefore, it might be concluded that ingredients present in both types of sausages and the way of packaging and storage limited the _L. monocytogenes_ growth. In AC sausages dried acerola, next to spices and spices extract was used. Acerola (_Malpiquia emarginata_) is frequently used in \"clean label\" meat products because it shows a promising antioxidant and antimicrobial efficiency due to its composition rich in phenolic compounds and vitamin C, which also have shown beneficial health effects [29]. Nevertheless, the formulation of AC sausages failed to inhibit the _L. monocytogenes_ growth, which was demonstrated in a growth potential coefficient higher than the threshold value of 0.5. There are numerous studies indicating the potential of the novel methods to suppress the bacterial growth in alternatively cured meat products including high isostatic pressures, activated plasma, pulse-field UV light, and active packaging, as well as the addition of natural ingredients with a potential inhibitory effect on pathogens i.e., essential oils of aromatic and medicinal plants, plant extracts with high polyphenols concentration, acidified whey, honey, and other bee products [16]. These novel methods may offer AC products a better protection from _L. monocytogenes_ growth than those used currently. In the present study alternatively cured and nitrite cured cooked sausages produced in the same meat-processing plant under the same hygienic conditions were used. The results obtained in the study showed significant differences between products in _L.