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Optimization of methods to grow spinach hydroponically in the presence of antagonists and their activity against Escherichia coli

Dhulappanavar, Gayatri Rajashekhar LU (2017) KLGM01 20152
Food Technology and Nutrition (M.Sc.)
Abstract
Fruits and leafy vegetables are the major target of pathogenic E.coli outbreaks. Usually soil and other contaminants present in the land provides easy pathway for pathogenic bacteria to enter the plant body. Later upon consumption of such infected food lead to various health problems. To overcome such outbreaks, during our study one of the leafy vegetable spinach was used as a medium to understand the cause and use of antagonists to prevent the cause of such outbreaks at lab scale. In our present study, our main aim is to check the antagonistic effect of six Pseudomonas isolates against pathogenic E.coli. In order to make sure that other bacteria or contaminants does not affect our studies, hydroponic system was chosen to grow spinach... (More)
Fruits and leafy vegetables are the major target of pathogenic E.coli outbreaks. Usually soil and other contaminants present in the land provides easy pathway for pathogenic bacteria to enter the plant body. Later upon consumption of such infected food lead to various health problems. To overcome such outbreaks, during our study one of the leafy vegetable spinach was used as a medium to understand the cause and use of antagonists to prevent the cause of such outbreaks at lab scale. In our present study, our main aim is to check the antagonistic effect of six Pseudomonas isolates against pathogenic E.coli. In order to make sure that other bacteria or contaminants does not affect our studies, hydroponic system was chosen to grow spinach plants. The entire study was divided into five different experiments. The aim of: experiment 1 was to optimise the conditions for hydroponic spinach plants at lab scale; experiment 2 to check the effect of antagonists on seed sprouting; experiment 3 to check the presence of antagonists on plants after seed incubation; experiment 4 to check the effect of antagonists against E.coli on plants after seed incubation; experiment 5 to check the effect of antagonists against E.coli after leaf dipping. The non-selective media (TSA) plate count results showed that the antagonist d of Pseudomonas origin significantly lowered total colony count from 9.05 to 7.86 log cfu/g (p<0.01) when compared to negative control without antagonist. The selective media (ECBA) plate count results showed that antagonist a and f lowered E.coli colony count from 3.74 to 2.78 and 2.78 cfu/g respectively (p<0.01) when compared to negative control without antagonist. (Less)
Popular Abstract
‘Good food each day keeps illness away’. Having said this, these days it is quite challenging to prevent foods like fruits, leafy vegetables, canned or ready to eat foods getting contaminated by bad bacteria that cause disease. These bacteria could enter our food either at the early stage of production, or on the way to our plates. In order to prevent such harmful events, this project was carried out.

The main idea of this project was to prevent contamination and establishment of Escherichia coli (E. coli) on spinach plants that were grown using hydroponics. A hydroponic system is a closed system where liquid medium is used instead of soil to grow plants. This liquid media contains everything that the plants need to grow, and,... (More)
‘Good food each day keeps illness away’. Having said this, these days it is quite challenging to prevent foods like fruits, leafy vegetables, canned or ready to eat foods getting contaminated by bad bacteria that cause disease. These bacteria could enter our food either at the early stage of production, or on the way to our plates. In order to prevent such harmful events, this project was carried out.

The main idea of this project was to prevent contamination and establishment of Escherichia coli (E. coli) on spinach plants that were grown using hydroponics. A hydroponic system is a closed system where liquid medium is used instead of soil to grow plants. This liquid media contains everything that the plants need to grow, and, conditions like temperature, humidity, air circulation and sterility can be controlled easily. During the study, the plants were added 6 different Pseudomonas isolates and E.coli to check the antagonistic activity of those isolates against E.coli. Throughout the project five separate experiments were carried out, among which first two experiments were focussed on optimisation of: i) the liquid medium required to grow spinach plants in hydroponic system, ii) the period of time required for spinach seeds to sprout and even the time required for sprouted seeds to grow into plants inside hydroponic chamber. Further, the optimised aspects were used to carry out the third experiment. Additionally, microbiological techniques and molecular tools were used to confirm the survival of Pseudomonas isolates inside spinach plants, which were grown hydroponically for a period of 1 week. Furthermore, experiment 4 and 5 were performed to check the effect of Pseudomonas isolates against E.coli.

The results showed that 2 out of 6 isolates of Pseudomonas bacteria had the ability to prevent the growth of E.coli on spinach plants. In the future, if these bacteria prove to have no negative effects on humans and if it safe to use them on produce grown agriculturally, they will be used to carry out further experiments on a larger scale in the field. These bacteria could be of great importance to make food produced through farming safe for consumption. (Less)
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author
Dhulappanavar, Gayatri Rajashekhar LU
supervisor
organization
course
KLGM01 20152
year
type
H2 - Master's Degree (Two Years)
subject
keywords
Hydroponic system, Food Technology, Food Hygiene, Spinach, Pseudomonas isolates, E.coli, livsmedelsteknologi
language
English
id
8903771
date added to LUP
2017-03-31 09:24:10
date last changed
2017-03-31 09:24:10
@misc{8903771,
  abstract     = {Fruits and leafy vegetables are the major target of pathogenic E.coli outbreaks. Usually soil and other contaminants present in the land provides easy pathway for pathogenic bacteria to enter the plant body. Later upon consumption of such infected food lead to various health problems. To overcome such outbreaks, during our study one of the leafy vegetable spinach was used as a medium to understand the cause and use of antagonists to prevent the cause of such outbreaks at lab scale. In our present study, our main aim is to check the antagonistic effect of six Pseudomonas isolates against pathogenic E.coli. In order to make sure that other bacteria or contaminants does not affect our studies, hydroponic system was chosen to grow spinach plants. The entire study was divided into five different experiments. The aim of: experiment 1 was to optimise the conditions for hydroponic spinach plants at lab scale; experiment 2 to check the effect of antagonists on seed sprouting; experiment 3 to check the presence of antagonists on plants after seed incubation; experiment 4 to check the effect of antagonists against E.coli on plants after seed incubation; experiment 5 to check the effect of antagonists against E.coli after leaf dipping. The non-selective media (TSA) plate count results showed that the antagonist d of Pseudomonas origin significantly lowered total colony count from 9.05 to 7.86 log cfu/g (p<0.01) when compared to negative control without antagonist. The selective media (ECBA) plate count results showed that antagonist a and f lowered E.coli colony count from 3.74 to 2.78 and 2.78 cfu/g respectively (p<0.01) when compared to negative control without antagonist.},
  author       = {Dhulappanavar, Gayatri Rajashekhar},
  keyword      = {Hydroponic system,Food Technology,Food Hygiene,Spinach,Pseudomonas isolates,E.coli,livsmedelsteknologi},
  language     = {eng},
  note         = {Student Paper},
  title        = {Optimization of methods to grow spinach hydroponically in the presence of antagonists and their activity against Escherichia coli},
  year         = {2017},
}