Agricultural Research Management Information System

Home
Research Summary
Search
About Us
- ARMIS
- Brochure
Contact Us
Report
User Request
Data Input
Help
- Operation Manual
  - PDF
  - Video
- Program Area & Commodity
We have reached 37600 number of research entries at this moment.

- Logout

Research Detail

Home
Research
Detail

Complete Microbiological Analysis of Citrus Fruits and the Effect of Heat on Microbial Load & Antimicrobial Activity

Sheikh Al Mamun
Department of Microbiology, Stamford University Bangladesh, 51 Siddeswari Road, Dhaka 1217, Bangladesh

Farahnaaz Feroz*
Department of Microbiology, Stamford University Bangladesh, 51 Siddeswari Road, Dhaka 1217, Bangladesh

Abstract/ Executive Summary:

Citrus fruits are very popular both for raw consumption as well as juices, jam and jelly. Besides the nutritional properties, citrus fruits exhibit some antimicrobial properties by containing polymethoxylated flavones, flavonoids, steroids, saponins, alkaloids, reducing sugars, terpenoids etc. But sometimes such fruits can be contaminated with bacteria which find their ways in the consumers causing different disease conditions. The current study revealed the microbial load of Lemon, Lotkone, Orange, Malta and Amoloki and the study showed complete absence of Klebsiella spp. and Escherichia coli. The highest total viable bacterial and fungal count was 4.2×104 cfu/g and 2.0×105 cfu/g respectively. Pseudomonas spp. was the highest predominating bacteria with lower degree of contamination by Listeria spp. and Staphylococcus spp. Applying heat at 60^oC for 30 minutes, 1 hour and 2 hours proved the reduction of bacteria over time. Antibacterial activity after heat treatment for all cases (after 30 minutes, 1 hour and 2 hours). Antibacterial activity was lowest after 2 hours of heat treatment for amoloki and there was no such activity at all for Amra after 2 hours. Other citrus fruits surprisingly showed no antibacterial activity after heat treatment.

Keywords: Citrus fruits, Microbial load, Antibacterial activity, Heat treatment

Location: Microbiological Laboratory at Stamford University, Bangladesh, Dhaka

Start Date:

End Date:

Program Area: Resource Development and Management

Commodity: Microbiological aspect, Citrus

Objectives:

Current study attempted to identify the microbiological loads of citrus fruits, collected from Dhaka City, Bangladesh and to elucidate the effect of heat on the microorganisms, in an attempt to set up heat as an operative, low cost and easy to use method of sterilization. The current study also describe the antimicrobial activity of the citrus fruits and whether heat will affect its actions

Methodology:

Samples. Six different raw citrus fruits (Lemon, Amoloki, Amra, Orange, Lotkone and Malta) were collected from public roadside markets early in the morning. All samples were instantly shifted to the Microbiological Laboratory at Stamford University, Bangladesh, Dhaka and subjected to microbiological investigation.

Total bacterial and fungal analysis. Total bacterial and fungal analysis was carried out as mentioned in Feroz et al. (18). Ten grams of the sample was homogenized for 1 min in sterilized 90 ml of physiological saline using a stomacher (Model No. 061-21001; Atect Co. Ltd, Japan). From this homogenate, serial dilutions were arrayed and surface plated (0.1 ml, in duplicate) on Nutrient Agar (NA) and Sabaroud Dextrose Agar (SDA). NA plates were incubated at 37^oC for 48 hours, while the SDA plates were incubated at 25^oC for 5 days. After incubation, the bacterial counts and fungal counts per gram were considered from NA plates and SDA plates, gradually.

Identification of coliform bacteria. From the dilution 10-2 & 10-3 , the 0.1ml sample was spread onto MacConkey agar for the detection of total coliform. The plates were incubated at 37^oC for 24 hours. Identification of Pseudomonas spp. and Staphylococcus spp. and Listeria spp. Staphylococcus spp., Pseudomonas spp. and Listeria spp. were identified from the Mannitol Salt Agar (MSA), Pseudomonas agar and Listeria identification media respectively after spreading 0.1 ml of the diluted samples on these media. Results were observed after 24 hours incubation at 37^oC.

Determining Antimicrobial Activity. Determination of anti-bacterial activity was performed by using the agar well diffusion method as previously described. Culture suspensions of 9 laboratory bacterial strains (Bacillus spp., Pseudomonas spp., Vibrio spp., Escherichia coli, Klebsiella spp., Staphylococcus spp., Listeria spp., Salmonella spp., and Aeromonas spp.) were prepared in normal saline equivalent with the turbidity of the McFarland standard. Each of the test bacterial lawn was made by separately spreading evenly over the separate Muller-Hinton agar (MHA). Wells with volumes of 8 mm³ were made through the MHA. Each of the crashed fruit blends (100 µl) was added to the wells along with the disc of gentamicin 10 µg as the positive control and an aliquot of 100µ l normal saline was used as the negative control. After drying the plates were then incubated at 37°C for 12-18 hours.

Source of Information: Stamford Journal of Microbiology, 2017. Vol. 7, Issue 1, p. 28-32 ISSN: 2074-5346 (Print); 2408-8846 (Online)

Article Link (Online Journal): DOI: https://doi.org/10.3329/sjm.v7i1.40068

Funding Source:

Budget:

Total Budget (Tk.) :

Achievement/Findings:

Overall, the findings of this study clearly indicate a complete bacteriological profile of local market citrus fruits, which is of public health significance. Further studies with some advanced molecular settings for the better detection of the pathogens as well as some good solvent extraction methods need to be established to use citrus fruits as a potential therapeutic agent which may reduce the use of conventional drugs for the remedy of various diseases.

Knowledge Management: Journal