Comparison of the effect of storage environment on tuber contamination with Erwinia carotovora

One tonne boxes of seed potatoes cv. Désirée contaminated with Erwinia carotovora were held in four different types of farm stores. In general, contamination fell rapidly immediately after harvest and rose later in the storage season. The extent of these changes varied considerably with store type. The greatest reduction was from a log count of 5.5 to 2.1 after one month storage, followed by a rise to 5.1 prior to planting. No relationship was found between store temperature, relative humidity and change in contamination. There was some evidence that reduction in contamination was related to duration of ventilation, and rise in contamination to onset of sprouting. A sample held at a constant 4°C showed little reduction in contamination, and no rise occurred later in the storage season.