## 4 Use of Modified Atmosphere Packaging (MAP)
While some additional investment in processing machinery is necessary, failing to control the proper balance can have negative consequences (Table 5). The temperature of storage, transport (shipment) and turnover of MAP-packed commodities is very important to maintain their quality. [PERSON] et al. [84] showed that the shelf life of fresh-cut green bell pepper MAP packed is limited to 14 and 21 days when stored at 10 \({}^{\circ}\)C and 5 \({}^{\circ}\)C, respectively. [PERSON] et al. [85] pointed out that developing a functional and practical MAP system for any perishable commodity requires knowledge about the influence of the temperature on film permeability characteristics, the respiratory processes and the lower O2 limit. [PERSON] et al. [82] summarised the optimum temperature range for MAP for deciduous, subtropical and tropical tree fruit and vegetables. They pointed out that, depending on the species, the optimum range could be varied from 0 \({}^{\circ}\)C to even 25 \({}^{\circ}\)C. \begin{table}
\begin{tabular}{c p{227.6 pt}} \hline \hline
**Medium** & \multicolumn{1}{c}{**Function**} \\ \hline Oxygen O2 & Oxygen is low solubility in water odourless and colourless gas. It enhances oxidation and darkening process in foods (including fruit and vegetables). Because is required for the growth of many pathogenic strains of bacteria and fungi, therefore a reduction of its concentration in packages prolongs the shelf life of food. \\ \hline Nitrogen N2 & Nitrogen is non-reactive, non-flammable, inert, colourless, and odourless gas. Its density is lower than air and is characterised by low water solubility. It serves as a neutral filling for modified atmosphere packaging with a regulated oxygen-to-carbon dioxide ratio. May contribute to slowing oxidation and growth of aerobic bacteria without suspending the growth of anaerobic strains. \\ \hline Carbon dioxide CO2 & Carbon dioxide is colourless and odourless (in low concentration) gas. It is lipid soluble and dissolves readily in water giving carbonic acid, which causes the increase of acidity of the solution lowers the pH and has a positive effect on the microbiological stability of packed food. Carbon dioxide is characterised by bacteriostatic and fungistatic properties. It is generally effective in fresh fruit and vegetables where the normal spoilage organisms consist of aerobic, Gram-negative psychotropic bacteria. In the low storage temperature, a higher antimicrobial effect is observed. Using a high concentration of carbon dioxide in MAP, the susceptibility of fruit and vegetables to CO2 injuries should be taken into consideration. \\ \hline Carbon monoxide CO & Carbon monoxide is a colourless, tasteless and odourless gas with low water solubility, quite soluble in some organic solvents. It little slows down the growth of some microorganisms, but it is not widely used in the food industry due to its properties (highly reactive and very inflammable). Carbon monoxide can prevent browning processes for example for packed lettuce. \\ \hline Noble gases & Helium (He), Argon (Ar), Xenon (Xe) and Neon (Ne) non-very reactive gases used to fill many packages of processed foods. \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Effect of gases used in MAP technology on the shelf life of fresh products [1].