Microbial characterization of spoiled food and the screening for the potential antibiotics that inhibit the identified food pathogens

Author Name(s): *Mary Joseph
Author Email: jsusanmary@gmail.com


In the current era of fast and corporate life style one of the major problems faced by the individuals is the health hazards caused by spoiled or improperly maintained food. Currently there is an extensive increase in the usage of packaged and stored foods that would always be a hub for all the diseases caused by various food borne pathogens. In view of these problems the current work aims to characterize the microbial pathogens in selected spoiled food samples followed by their identification. It involves the isolation of bacteria from the selected spoiled food samples, Preparation of their pure cultures followed by their identification based on Biochemical tests as per Bergey’s Manual. Once the bacterial pathogens are identified, the study was extended towards the screening of the antibiotics that are capable of inhibiting the growth of these pathogens. The work concludes by proposing the specific antibiotics that can be used towards the infections or diseases caused due to the consumption of spoiled food contaminated with the specific organism under study. Once the results are validated using the clinical study they can be applicable directly for treating the abnormalities caused by food borne pathogens. The work can be further extended toward the identification of fungal pathogens.


Spoilage is a complex process and it involves physical, chemical, biochemical and biological changes [1]. Microbial contamination of ready-to-eat foods and beverages sold by street vendors has become a global health problem [2]. An analysis of the street vended food stuffs revealed the presence of the bacteria Staphylococcus faecalis, Escherichia coli, Staphylococcus aureus, Bacillus Species, Klebsiella species and Pseudomonas species as the contaminating pathogens [3]. It is a metabolic process that causes Foods to be undesirable or unacceptable for human consumption due to changes in sensory characteristics [4]. Most of the spoilage is due to the microbial contamination of the food either by bacteria or by fungi. Bacteria are the first contaminants in the food when compared to fungi. Microbial pathogens in food cause an estimated 6.5-33 million cases of human illness and up to 9,000 deaths in the United States each year [5]. Foodborne pathogens are responsible for millions of cases of infectious gastrointestinal diseases each year, costing billions of dollars in medical care and lost Productivity [6]. Factors that affect food spoilage are pH, moisture content, water activity, oxidation-reduction potential, physical structure of the food, available nutrients, presence of antimicrobial agents, temperature, relative humidity, carbon dioxide or oxygen and type and numbers of microorganisms in the food. Routes of microbial contamination of food are air, dust, soil, water, plants, animals, animal feed, food handlers, and food utensils, cross contamination, unsafe temperature and pests [7]. The microbes will not only cause the food to be undesirable for consumption but also causes many dreadful diseases when consumed. The diseases caused due to the food born pathogens mostly alter the gastrointestinal tract and throat condition. They often cause diarrhoea, Nausea, Vomiting, dehydration etc. The cases reported with these symptoms and causes are enormously increasing with the advancement in the use of packaged food products. Most of these bacteria can be inhibited from contaminating the food by maintaining high acidity and low water activity level.


From the current work it is identified that the most common organisms inhabiting the spoiled foods are Bacillus alvei, Corynebacterium kutscheri, Bacillus Badius and staphylococcus species.Once the bacterial pathogens were identified the work was further extended to screen the antibiotic sensitivity of these test bacteria against the four selected antibiotics, Tetracycline, Azithromycin, Clotrimazole and Ampicillin. The results from the sensitivity study showed that all the selected antibiotics had a good inhibitory activity against the test pathogens except in case of Corynebacterium kutscheri to the antibiotics Ampicillin and Azithromycin.
From the results furnished above it can be concluded that these selected antibiotics can be used in the treatment of the minor ailments caused due to the food borne pathogens. Further bthe use of these antibiotics within the limited concentration in the preservative foods can be emphasized; however this can be validated only with the support of the clinical data.

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