# Plant Organic Acids as Natural Inhibitors of Foodborne Pathogens
## 4 Discussion  
In vegetables and fruit juices, many organic acids have been found, including acetic acid, ascorbic acid, aspartic acid, benzoic acid, butyric acid, citric acid, formic acid, gluconic acid, glutamic acid, glycolic acid, isoascorbic acid, lactic acid, malic acid, nicotinic acid, oxalic acid, propionic acid, sorbic acid, succinic acid, and tartaric acid [29]. Some organic acids, such as acetic, ascorbic, citric, lactic, and malic acids, are commonly used as traditional food preservatives [30]. They are also widely used as preservatives in the food industry. According to European legislation, five acids are known as E-additives: E200 sorbic acid, E210 benzoic acid, E260 acetic acid, E270 lactic acid, and E280 propionic acid. Several acids are used as acidifiers: E260 acetic acid, E270 lactic acid, E296 malic acid, E230 ascorbic acid, E330 citric acid, E334 tartaric acid, E355 adipic acid, and E363 succinic acid [19]. The antibacterial activity of organic acids has been confirmed in numerous studies. However, most research has focused on acetic acid, citric acid, formic acid, and malic acid. After searching the PubMed and Scopus databases, it appears that the present work is the first to examine the antibacterial activity of as many as 21 organic acids. We demonstrated that most organic acids exhibit bacteriostatic effects at levels ranging from 0.31 to 5 mg/mL. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Organic Acid**} & \multirow{2}{*}{**Predicted**} & \multirow{2}{*}{\begin{tabular}{c} **Mean MIC** \\ **[mg/mL] against** \\ **Bacteria/Fungi** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Density** \\ **[g/mL]** \\ \end{tabular} } & \multirow{2}{*}{\
\begin{tabular}{c} **Mean MIC in 1 kg** \\ **of Food Product [mg/kg]** \\ **against Bacteria/Fungi** \\ \end{tabular} } & \multirow{2}{*}{
\begin{tabular}{c} **Safe Use as a Food** \\ **of Food Product [mg/kg]** \\ **against Bacteria/Fungi** \\ \end{tabular} } \\ \hline Acetic acid & 333 & 1.72/7.5 & 1.05 & 1638/7142 & No/No \\ \hline Aminoacetic acid & 3340 & 70.83/\textgreater{}100 & 1.61 & 43,994/\textgreater{}62,112 & No/No \\ \hline Ascorbic acid & 3367 & 2.66/83.33 & 1.65 & 1612/50,503 & Yes/No \\ \hline Benzoic acid & 290 & 0.63/7.08 & 1.27 & 496/5574 & No/No \\ \hline Caproic acid & 94 & 3.75/7.5 & 0.93 & 4032/8065 & No/No \\ \hline Chlorogenic acid & 5000 & 1.72/5.63 & 1.28 & 1344/4398 & Yes/Yes \\ \hline Citric acid & 80 & 2.97/8.33 & 1.66 & 1789/5018 & No/No \\ \hline Formic acid & 162 & 1.56/7.5 & 1.22 & 1279/6148 & No/No \\ \hline Fumaric acid & 1350 & 2.66/14.17 & 1.64 & 1622/8640 & No/No \\ \hline Glutamic acid & 4500 & 7.50/\textgreater{}100 & 1.46 & 5137/\textgreater{}68,493 & No/No \\ \hline Malic acid & 2497 & 1.33/50 & 1.61 & 826/31,055 & Yes/No \\ \hline Nicotinic acid & 3720 & 1.25/15 & 1.47 & 850/10,204 & Yes/No \\ \hline Oleic acid & 48 & 7.50/50 & 0.895 & 8380/55,866 & No/No \\ \hline Oxalic acid & 660 & 2.27/16.67 & 1.9 & 1195/8774 & No/No \\ \hline Palmitic acid & 990 & 27.5/30 & 0.85 & 32,706/35,294 & No/No \\ \hline Rosmarinic acid & 5000 & 1.88/6.46 & 1.55 & 1213/4168 & Yes/Yes \\ \hline Salicylic acid & 1190 & 0.67/7.08 & 1.44 & 465/4917 & Yes/No \\ \hline Succinic acid & 2260 & 2.27/83.33 & 1.56 & 1455/53,417 & Yes/No \\ \hline Tannic acid & 2260 & 2.27/52.08 & 2.12 & 1071/24,566 & Yes/No \\ \hline Tartaric acid & 2497 & 2.97/75 & 1.79 & 1659/41,899 & Yes/No \\ \hline Valeric acid & 134 & 2.97/5.0 & 0.94 & 3160/5319 & No/No \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Relationship between MIC values and LD50 in mg/kg and the safety of studied organic acids as food preservatives. The inhibitory concentrations against bacteria reported in the literature vary. Some inhibitory levels are similar to those in the present study. [PERSON] et al. [31] showed that vancomycin-resistant _Enterococcus faecium_ is sensitive to acetic acid at a dose of 2 mg/mL, citric acid at doses of 1-4.1 mg/mL, and formic acid at a dose of 1 mg/mL.