Effect of modified atmosphere packaging on the shelf life of sliced wheat flour bread

The application of modified atmospheres packaging (MAP) of sliced bread with different aw, moisture content and pH values, with or without preservative added (calcium propionate) and at different storage temperatures, has been studied with the aim of establishing the effect of MAP on the shelf-life of the selected product. Four atmospheres were tested per batch: 100% N2, 20% CO2/80% N2, 50% CO2/50% N2 and a standard air control. In samples without added preservative in CO2:N2 (50:50), the increases in shelf life were 117% and 158% at 22-25 degrees C and 15-20 degrees C, respectively. In samples with added preservative in 100% N2, shelf life was increased by 116%. Samples with added preservative in 20% CO2:80% N2 increased shelf life by 150% and 131% at 22-25 degrees C and 15-20 degrees C, respectively. By increasing the CO2 concentration to 50%, the increases in shelf life of the samples with added preservative were 167% and 195% at 22-25 degrees C and 15-20 degrees C, respectively.