Isolation and Identification of Fungi from Spoiled food samples and testing their Antibiotic efficacy

Author Name: *Jaspreet Kaur Multhani
Author Email: multani.jaspreet@gmail.com

Abstract

Spoilage is the process in which food deteriorates to the point where in it is not edible to humans. Micro-organisms are mainly responsible for food spoilage which includes bacteria and fungi. A study was carried out on the fruits that were spoiled due to the fungal infection. Rhizopus, Trichoderma, Penicillium and Aspergillus were isolated from these foods and were cultured. As fungal species are well known for their antibacterial nature the focus of the work was to use these fungi for the production of antibiotics that are of huge industrial importance. Pure cultures of various bacterial pathogens like Pseudomonas, Staphylococcus aureus, Streptococcus agalactiae and Edwardella were obtained and were tested for their sensitivity towards the identified fungus using kirby bauer method. The sensitivity test results showed that several fungi isolated from the spoiled food had the potential to produce the antibiotics that could inhibit the growth of the human bacterial pathogens. These results can be employed for the industrial scale production of antibiotics from fungus and the use of spoiled food substances as the source for the isolation of useful Fungus. The secondary metabolite extract of Trichoderma showed good zones of inhibition against the test bacterial samples with the range of 24mm, 28mm and 9mm against Staphlococcus aureus, Streptococcus agalactiae and Edwardella respectively. Rhizopus could not exhibit the antibacterial activity against the test bacteria. The metabolites of Penicillium showed the zones ranging from 17mm and 7mm against Streptococcus and agalactiae respectively. Aspergillus metabolites exhibited the inhibition zones ranging 14mm and 18mm against Pseudomonas and Edwardella respectively. From the results it can be concluded that the spoiled food can be used as a source for the isolation of the fungal species capable of producing potential antibiotics.

Keywords

Antibacterial, Rhizopus, Trichoderma, Staphlococcus aureus, Streptococcus agalactiae, Edwardella, Pseudomonas, Sensitivity Test

Introduction

Food microbiology is the study of the microorganisms that inhabit, create, or contaminate food. In food microbiology one of the major importance is the study of microorganisms causing food spoilage [1]. Food borne pathogens are the leading causes of illness and death in undeveloped countries, killing approximately 1.8 million people annually [2]. In developed countries, food borne pathogens are responsible for millions of cases of infectious gastrointestinal diseases each year, costing billions of dollars in medical care and lost productivity [3]. New food borne pathogens and food borne diseases are likely to emerge, driven by factors such as pathogen evolution, changes in agricultural and food manufacturing practices, and changes to the human host status. There are growing concerns that terrorists could use pathogens to contaminate food and water supplies in attempts to incapacitate thousands of people and disrupt economic growth [4]. Food contamination and spoilage is most commonly seen, which can give rise to many health hazards. Thus, to overcome these problems the present study was undertaken. The main principle behind the focus of the study is to analyze various fungus infected fruits and to check the antimicrobial activity by extracting fungal secondary metabolites. The study is to find out whether the fungal metabolites have the capability to inhibit bacterial pathogens. Human pathogens that cause food born infections or food poisoning can be prevented by the use of these antibiotics or their modified forms either as food preservatives or as a normal antibiotic to cure food borne bacteria infections.

Conclusion

From the present study it was concluded that the different fungi isolated from the infected fruits have the capability to inhibit the growth of the pathogenic bacteria as identified by the antibacterial activity check using Kirby bauer method. Each fungal extract showed a specific range of inhibition against pathogenic bacteria. These results indicate that the secondary metabolites of fungus have an antibacterial activity that can inhibit the pathogenic strains of bacteria that are usually responsible for various diseases. Based on the results it can be inferred that the fungi isolated from the spoiled food would possess the inherent potential to inhibit the growth of the bacteria involved in various pathogenic processes. Thus the fungi can be used in the preparation of extracts that can be modified (so as to make it non non toxic for human consumption) to be used as food preservatives. The fungi can also be used for the preparation of antibiotics that can act against the food borne bacterial infections.

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