# In Situ Interaction of Enterocin A/P with _Staphylococcus aureus_ SA5 in Goat Milk Lump Cheese
## 4 Discussion  
Healthy and safe dairy products are one of major objectives for producers and consumers who are increasingly demanding healthier and safer dairy products [17]. As formerly mentioned, staphylococci are found in frequent contaminants of raw milk and products made from it [9; 11]. Some strains of _S. aureus_ can produce hemolysis or enterotoxins, which can influence the technological process but also the health of consumers [10]. A promising approach of how to prevent unrequested parameters is represent by bacteriocins. For example, in our previous studies using enterocins it was reported that Enterocin CCM4231 showed anti-staphylococcal effects in yogurt and also in Sunar (milk nourishment for suckling babies) [18]. The reduction of _S. aureus_ Oxford 209P in Sunar and _S. aureus_ SA1 in yogurt was found with a difference of up to 3.0 log cycles. However, direct inhibitory activity of Enterocin 4231 was detected only immediately after its addition (400 AU/mL) in yogurt and after three and a half hours (200 AU/mL). Another problem of staphylococci is their increasing antibiotic resistance. When staphylococci cause mastitis in dairy and are also antibiotic resistant, milk can be influenced negatively. It is known that staphylococci form 24% of all mastitis cases in dairy [19]. Toxinogenic _S. aureus_ has regularly appeared in milk in low numbers and its growth during uncontrolled fermentation of milk and/or young cheese may be intensive [20]. [PERSON] et al. [21] reported that milk and cheeses were implicated in 1-5% of the total bacterial outbreaks in food-borne diseases with the most frequently identified _S. aureus_ as a causative agent. Therefore, utilizing the antimicrobial effect of bacteriocins and enterocins has an advantage not only for the maintenance of suitable technological conditions during product processing but also for protecting the health of consumers. [PERSON] [22] reported enterocins as perspective bacteriocins \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Sampling** & **CV** & **EV** & **RV** \\ \hline
24 h/pH & 6.69 & 6.69 & 6.69 \\
72 h/pH & 4.66 & 4.38 & 4.39 \\
96 h/pH & 4.43 & 3.93 & 4.19 \\ \hline
24 h/LA & 0.21 & 0.21 & 0.21 \\
72 h/LA & 4.66 & 4.38 & 4.39 \\
96 h/LA & 3.58 & 3.71 & 2.58 \\ \hline
24 h/\({}^{\circ}\)SH & 56 & 56 & 44 \\
72 h/\({}^{\circ}\)SH & 94 & 93 & 98 \\
96 h/\({}^{\circ}\)SH & 115 & 90 & 110 \\ \hline \hline \end{tabular}  
* CV—control vat milk/cheese (with _S. aureus_ SA5 strain); EV—experimental vat milk/cheese (with _S. aureus_ SA5 and Enterocin A/P, 12,800 AU/mL); RV—reference vat milk/cheese (no additives); LA-lactic acid in g/100 g; \({}^{\circ}\)SH-acidity (Sokelth-Henkel method).  
\end{table} 
Table 2: The values of pH, lactic acid (g/100 g), and acidity (\({}^{\circ}\)SH) during cheese processing. to be used in the food industry. However, it is also necessary to add that the optimal use of bacteriocins within a multi-barrier system to inhibit spoilage microbiota requires a detailed knowledge of their nature and of those factors that may limit their effectiveness. Those factors may include the food structure and composition as well as the interaction of bacteriocin with the other microbiota [21]. Active acidity (pH) and titrable acidity (\"SH) and LA are parameters that can influence the ripening process during goat milk lump cheese processing [23]. During our experiment, the changes in acidity (\"SH) were noted in the period from 24 h up to 72 h. The lowest value was in the RV (44 \"SH), while in the EV and CV it was the same (56 \"SH). However, almost the same values were measured at 72 h and then also at 96 h in the CV and RV. In the EV cheese (with SA5 and Ent M), a lower \"SH was measured than in the RV and CV (there were the same values measured). This acidity was comparable with that measured in cow lump cheese treated with Enterocin CCM4231 at day 7 (129 \"SH) [23]. It seems that the pH was not negatively influenced in our cheeses; however, it was lower in the EV than in the RV and CV.