Microbial Load and Innocuousness of the Extract of Plants Obtained from Banana Rachis Leachate Produced in Cuba Inhibitors in COVID-19: Lessons Learnt from Transplantation

as it is a product of the same plant, it has essential nutrients (N, K, Fe, Mn, Na, Cu) that can be reused for the crop itself [5-7]. These plant extracts applied to banana seedlings under nursery conditions, have proven to be effective in the growth of them, with a significant increase in the variables (height, number of leaves, as well as the total length and fresh and dry weight of the roots) [8,9]. Besides the nutritional value of this extract of plants, its potential as a pest and pathogen controller has been studied. This is attributed to the large number of microorganisms present in them [10,11]. Special interest has aroused the use of leachates to reduce the infective process of the The objective of this research was to determine the microbiological composition and innocuousness of banana leachate, obtained at the Research Institute of Tropical Roots and Tuber Crops (INIVIT) in Santo Domingo, Villa Clara, Cuba. The determination of the microbial load and innocuousness of the leachate analyzed was carried out through established procedures at the Microbiology Laboratory of the Center for Genetic Engineering and Biotechnology (CIGB). The results obtained in the research are the scientific basis for encouraging the use of banana rachis leachate, as a high value-added product. The microbial load determined in this study 4.4 x 106 CFU/mL from bacteria of the genus Bacillus sp. and its innocuousness as it is free of pathogenic microorganisms, such as Escherichia coli and Salmonella sp., were findings of great importance. The research helps to encourage the use of a crop residue, underused in the production process of plantains and bananas in Cuba.

Other existing studies support the rachis use for other purposes, such as: ingredient for the production of flours, paper, ferments, livestock fodder, and even as a seed germination mechanism [16][17][18]. At the Research Institute of Tropical Roots and Tuber Crops (INIVIT), a constant production volume of 200 L of extract of plants was obtained by the rachis decomposition of Musa AAA, subgroup Cavendish, cultivar 'Gran enano', from 700 kg of rachis, for an efficiency of 30 % by the end of 2019 and beginning of 2020 [1].
The authors propose the rachis leachate as a way to take advantage of an invaluable residue in the current economic situation of the Cuban agriculture.The INIVIT devotes efforts through its research-development programs and collaboration with scientific centers, to the study of rachis leachate production processes, its components, nutritional effect and disease managements.
Nowadays, investigations aimed at the chemical characterization of rachis leachates of plantains and bananas, have received more attention than the studies dedicated to the detection of microorganisms or bioload present in them [8,9,13]. This research carried out in collaboration with the Center for Genetic Engineering and Biotechnology (CIGB) aims to determine the microbiological composition and innocuousness of banana leachate, obtained at the INIVIT, to understand the action mechanism as a biological controller, improve the production efficiency and encourage its use in organic and sustainable production systems.

Materials and Methods
The determination of the microbial load and innocuousness

Procedure Performed for Bioload Determination
Ten mL of the sample were taken and added in 90 mL of Peptone Salt Solution. From this first dilution, serial dilutions were made up to 10-5. Later, 1 mL was filtered in duplicate of the dilutions 10-3, 10-4 and 10-5. The membranes were placed in plates, containing Triptone Soy Agar and incubated from 30-350C, for a period of 72 hours.

Procedure Performed for the Determination of Escherichia Coli
Ten mL of the first dilution described above were taken and

Results and Discussion
After the incubation period of each one of the determinations, it was obtained as a relative result to the Bioload, that in the dilution 10-5 grew 4l and 46 Colony Forming Units (CFU), respectively on each replica plate, so the concentration in the analyzed leachate  [19]. The chemical and microbiological characterization of an organic fertilizer, based on the use of residues from the harvest of bananas, showed that the greatest presence of microorganisms found were bacteria, although the genus was not identified [20]. The finding in this research is very important, due to the role of bacteria of the genus Bacillus, associated with the promotion of plant growth and control of pathogens [21][22][23][24][25]. A relevant aspect that distinguishes the bacteria of this genus is the ability to produce endospores, as a resistance mechanism to various types of stress [24,26,27].
The role of bacteria of the genus Bacillus as producers of growth phytoregulators, like cytokinins and gibberellins [28] could help to

Volume 29-Issue 3
interpret the effect of these extracts on the growth of plantain and banana vitroplants, reported by several authors. This reaffirms the importance of studying the composition of banana rachis leachates that determines its effectiveness in the control of diseases and growth promotion to improve its production.On the other hand, the microbial load determined in this study is above 1x106 CFU/ ml, considered as the necessary application dose, for these bacteria to exert their effect [29]. It is inferred that in the leachate obtained The results related to the determination of Escherichia coli and Salmonella sp. are reflected in Table 1.In relation to the leachate innocuousness, the results show the absence of Salmonella sp. and E. coli (Table 1), which is of most importance, since the international health organizations demand, as an indispensable control requirement for the use of these products, that these microorganisms must be at very low populations or absent to consider the product innocuous. The results obtained in terms of innocuousness and bacteria presence of the genus Bacillus, could encourage the use of rachis leachate in agro-ecological production systems and minimize the use of chemical substances that contaminate the environment, in addition to lower production costs, advantages that promote the use of this practice in the Cuban agro-ecosystems.