Effects of postharvest onion curing parameters on bulb rot caused by Pantoea agglomerans, Pantoea ananatis and Pantoea allii in storage

Abstract

Crop loss of onion bulbs during storage carries an exceptionally high economic impact because a large portion of the production expenses has been expended before storage. Because of this, it is important to define practices that can reduce onion bulb losses caused by storage rots. This study investigates the impact of various curing parameters on disease development resulting from infection by Pantoea agglomerans, P. ananatis and P. allii on onion bulb cultivars Vaquero and Redwing, during storage. Overall, both the incidence and mean rot severity were similar amongst the bulbs under comparable conditions regardless of the species of Pantoea inoculated, although a significant difference was detected between the two onion bulb cultivars. In addition, a significant reduction of storage rot was observed when curing temperatures were ≤35°C. At temperatures >35°C, a shorter curing duration (2 days vs 14 days) decreased the severity of bulb rot due to Pantoea. This increased understanding of the inter‐relationships between the parameters used for curing, and the incidence and severity of bulb rot caused by Pantoea helps provide guidance towards using the curing process as a means to reduce the level of damage resulting from post‐harvest storage rot.

Online measurement of temperature and relative humidity as marker tools for quality changes in onion bulbs during storage

“…Some of the bulbs from batch 1, which had the largest fraction of onions above 60 mm (S1 Table), the highest bulb weight (Table 1), and a high RH inside the box at beginning, developed partially translucent scales during drying. This indicated that the temperature was too high, and some of the cells collapsed and liquid moved from the interior into the intercellular spaces [16].…”

“…Harrow and Harris [9] noted that the maximum drying temperature for onions is 35 °C for 6 days. However, Schroeder, Humann [17] reported that the maximum drying temperature was 38 °C for 2 days, as higher temperatures for prolonged times would increase softening and enhance bacterial growth in cold storage due to the leaking of nutrients from the cells into the intercellular spaces, causing translucency [16]. During the cool down, the RH inside the boxes reached 25–32% (Fig 2B), and the levels were thus well below 60% RH, which is the recommended minimum level for preventing skin cracking during periods with high temperatures in drying [9, 13].…”

Silver Nanoparticles Offer Effective Control of Pathogenic Bacteria in a Wide Range of Food Products

“…Some of the most important are Enterobacter cloacae, Erwinia herbicola, Lelliottia amnigena, Pantoea ananatis, Pantoea agglomerans, Pantoea allii, Enterobacter aerogenes, Pseudomonas fluorescens and Streptomyces sp. [1][2][3][4][5][6]. A wide range of fungal species is similarly involved [2,[7][8][9].…”

Genomic Characterization, Formulation and Efficacy in Planta of a Siphoviridae and Podoviridae Protection Cocktail against the Bacterial Plant Pathogens Pectobacterium spp.

“…The most intensive production of onions occurs in Asia with 62.2%, Africa at 12.5% and Europe at 10.6%, with the global gross production value evaluated at up to US $42.1 million [3]. Appropriate control measures for onions against bacterial rot disease are difficult to achieve, given that at least 26 different fungi and bacteria are associated with this rot [4]. Onion rot may ultimately cause significant post-harvest losses, with disease beginning in the field and developing further during transit and storage [5].…”