Articles
Ralstonia pseudosolanacearum control: monitoring and containment measures in northern Italy tomato processing industry to prevent its spread
Article number
1445_30
Pages
213 – 218
Language
English
Abstract
Ralstonia pseudosolanacearum is the causal agent of a vascular wilt disease in more than 200 crop species, including tomato.
The bacterium can survive in tomato plant debris and many weeds; and can disperse in infested soil and irrigation water, which constitutes a possible source of inoculum.
The bacterium usually infects tomato plants through the roots.
Root-knot nematode, soil insects and cultivation practices can cause injuries to plant roots and allow penetration by bacteria. R. pseudosolanacearum-caused wilt in tomato can cause a 35-90% yield loss under high temperatures and high moisture conditions (Gupta et al., 2018). The purpose of this study was to simulate, for three consecutive years (from 2021 to 2023), what happens industrially during tomato processing, using processing tomatoes contaminated with Ralstonia, in order to assess the possible risk of transmission at the washing and wastewater treatment plant stages, and then to study the application of a sanitation protocol to inactivate the bacteria.
Ripe processing tomatoes: a) fully infested by R. pseudosolanacearum; b) infested and diluted with a specific quantity (5 times of non-infested tomatoes – used in order to mimic what usually occurs in a common receiving station of industrial tomato processing plant) were used.
These tomatoes (taken from the same infected field), were washed with precise volumes of washing-water applying a protocol of operations at the SSICA pilot plant able to mimic the industrial process.
All the wastewaters obtained from the pilot plant were treated with sodium hypochlorite (NaClO), using an experimental design made with the application of different concentrations/time combination, in order to evaluate the residual presence of the pathogen in the water samples, in tomatoes and in the MOT fractions (materials other than tomato). The results obtained after three years of experiments, indicated no presence of R. pseudosolanacearum in all the tomato and water samples after the application of the washing protocol treatment regardless the dosage or treatment time with NaClO, and the same for the tomatoes.
On the contrary, MOT showed presence of the bacterium in the basal part of the plants in the samples collected closest to the locus of the infection but never in tomato fruits.
This work represents the last step in a three years’ study commissioned from the Emilia Romagna Region that complete the statistical significance of the trials and confirms the results of the previous years of experimentation, opening to the possibility to harvest and process tomatoes coming from Ralstonia infested fields after the application of a correct protocol of operations to guarantee ambient, farms and industries as well as the consumers’ health.
The bacterium can survive in tomato plant debris and many weeds; and can disperse in infested soil and irrigation water, which constitutes a possible source of inoculum.
The bacterium usually infects tomato plants through the roots.
Root-knot nematode, soil insects and cultivation practices can cause injuries to plant roots and allow penetration by bacteria. R. pseudosolanacearum-caused wilt in tomato can cause a 35-90% yield loss under high temperatures and high moisture conditions (Gupta et al., 2018). The purpose of this study was to simulate, for three consecutive years (from 2021 to 2023), what happens industrially during tomato processing, using processing tomatoes contaminated with Ralstonia, in order to assess the possible risk of transmission at the washing and wastewater treatment plant stages, and then to study the application of a sanitation protocol to inactivate the bacteria.
Ripe processing tomatoes: a) fully infested by R. pseudosolanacearum; b) infested and diluted with a specific quantity (5 times of non-infested tomatoes – used in order to mimic what usually occurs in a common receiving station of industrial tomato processing plant) were used.
These tomatoes (taken from the same infected field), were washed with precise volumes of washing-water applying a protocol of operations at the SSICA pilot plant able to mimic the industrial process.
All the wastewaters obtained from the pilot plant were treated with sodium hypochlorite (NaClO), using an experimental design made with the application of different concentrations/time combination, in order to evaluate the residual presence of the pathogen in the water samples, in tomatoes and in the MOT fractions (materials other than tomato). The results obtained after three years of experiments, indicated no presence of R. pseudosolanacearum in all the tomato and water samples after the application of the washing protocol treatment regardless the dosage or treatment time with NaClO, and the same for the tomatoes.
On the contrary, MOT showed presence of the bacterium in the basal part of the plants in the samples collected closest to the locus of the infection but never in tomato fruits.
This work represents the last step in a three years’ study commissioned from the Emilia Romagna Region that complete the statistical significance of the trials and confirms the results of the previous years of experimentation, opening to the possibility to harvest and process tomatoes coming from Ralstonia infested fields after the application of a correct protocol of operations to guarantee ambient, farms and industries as well as the consumers’ health.
Authors
L. Sandei, R. Vitelli, A. Moreno Barreto , V. Fiazza, D. Brindani, A. Bozzardi, D. Imperiale, G. Chiusa, C. Delvago, R. Colla
Keywords
processing tomato, Ralstonia pseudosolanacearum, bacterial wilt, spoilage pathogen, tomato crop residues, disinfection protocol treatment
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