Increased shelf life of a bioherbicide through combining modified atmosphere packaging and low temperatures

The effects of air temperatures (4, 14 and 24 degrees C) and modified atmosphere packaging (MAP) (0% CO(2)/100% N(2); 20% CO(2)/ 80% N(2) or 40% CO(2)/60% N(2)) on vigour of a Sclerotinia minor barley formulation during 6 months storage were evaluated. The study was performed using a multilevel factorial experimental design and response surface methodology (RSM) and aimed to determine the optimum combination of the above factors that resulted in retention of S. minor vigour during storage. Temperature and storage duration are the main factors that affect S. minor vigour. CO(2) concentration had no effect on S. minor vigour during storage. However, oxygen displacement from storage containers by CO2 and N2 resulted in significant decrease of vigour reduction of S. minor as compared to ambient air control. An acceptable level of S. minor vigour reduction (ALVR) during storage was developed and determined to be ALVR = 31.79 +/- 14.8% (mean +/- 995% CI). Contour plot analysis indicated that the S. minor barley formulation at 0.4 water activity could be stored for 6, 12 or 26 weeks without exceeding the upper ALVR threshold (ca. 46%) at air temperatures not higher than 20, 17 or 11 degrees C, respectively.