The effect of leakage on the quality of gas-packed foodstuffs and the leak detection

The effect of package leakage on the quality of eight different gas-packed food products under different storage conditions and the non-destructive detection of leakage by using colour indicators were studied. Leakage was created in a sealing area of the packages by preparing microholes of 30 - 100 mm in diameter with tungsten thread. Microholes of 100 mm in diameter and under cannot easily be detected visually. With regard to the microbiological quality of food products in leaking packages as compared to that of intact packages, leakage most increased the growth of yeast and mould and less the growth of aerobic bacteria. Also, the growth of coliforms was enhanced by leakage, thereby, reducing hygienic quality. Sensory quality was affected by leakage in different ways depending on the food products tested. Most sensitive to leakage was sliced ham when stored under illumination, whereas, e.g., the sensory quality of marinated products was not clearly affected by leakage. With the exception of sliced ham and pizza, the leakage of a package was difficult to detect visually. However, the colour indicator tested detected leakage well. The colour indicator is most suitable for moist food products which spoil by microbial growth or colour change and when this spoilage is dependent on oxygen.