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

Isolation of Food-borne Microorganisms from Atlantic Mackerel and Disinfection of the Raw Fish by Radiation, Low Temperature and Combination Treatments

Manik Hossain
Department of Botany, Jahangirnagar University, Savar, Dhaka 1342, Bangladesh.

M Kamruzzam Munshi
Microbiology & Industrial Irradiation Division, Institute of Food & Radiation Biology, Atomic Energy Research Establishment, Ganakbari, Savar, Dhaka 1000, Bangladesh.

Rasheda Yasmin Shilpi
Department of Botany, Jahangirnagar University, Savar, Dhaka 1342, Bangladesh.

Harun-Or-Rashid
Microbiology & Industrial Irradiation Division, Institute of Food & Radiation Biology, Atomic Energy Research Establishment, Ganakbari, Savar, Dhaka 1000, Bangladesh.

Abstract/ Executive Summary:

An investigation was undertaken for the isolation and identification of fish-borne microorganisms from mackerel fish (Scomberomorus guttatus) collected from Savar Bazar. Radiation, low temperature (-20°C) and combination treatments were then applied for the decontamination of associated organisms. The ranges of total viable bacterial count, total coliform count, total faecal coliform count and total staphylococcal count varied from 6.5 x 10⁴ to 1.0⁴ x 10⁵, 2 x 10² to 4.0 x 10^2,0 to 1 x 10²and 4.4 x 10⁴ to 3.8 x 10⁴cfu/g respectively, while the total fungal count was nil. Sixty-four bacterial isolates were identified including Staphylococcus (19%), Micrococcus (11%), Enterobacter (8%), Klebsiella (17%), Bacillus (19%), Escherichia (17%) and Pseudomonas (9%). To disinfect the microorganisms, the samples were irradiated at different doses (0-10.0 kGy) of gamma irradiation. Total coliform and total faecal coliform bacteria were inactivated below the detectable level at 2.5 kGy of irradiation. The number of total viable bacteria decreased by three logs when irradiated at 5.0 kGy and the number of Staphylococcus bacteria were eliminated completely after the irradiation dose of 5.0 kGy. During frozen storage, the total viable bacterial counts were gradually declined in all the samples. After six months of storage the bacterial counts were decreased about one log in all of the samples. It has been observed that combination treatments (irradiation and freezing) are more effective than the single treatment for eliminating the fish-borne bacteria.

Keywords: Mackerel fish, Microbial contamination, Irradiation, Low temperature

Location: laboratory of Microbiology and Industrial Irradiation Division (MIID), Institute of Food and Radiation Biology (IFRB), Atomic Energy Research Establishment (AERE), Savar, Dhaka.

Start Date:

End Date:

Program Area: Pest Management

Commodity: Carp fish

Objectives:

An investigation was undertaken for the isolation and identification of fish-borne microorganisms from mackerel fish (Scomberomorus guttatus) collected from Savar Bazar.

Methodology:

Atlantic mackerel (Scomberomorus guttatus) was used for the studying of the microbial spoilage of the fish. Combinations of different parts of the fish such as muscle, skin, fin etc. were used as materials for the study. The fish samples were collected from Savar market. The samples were thawed by keeping at room temperature and then they were cut into different pieces and kept into the pre-sterilized polythene bags. The investigation was carried in the laboratory of Microbiology and Industrial Irradiation Division (MIID), Institute of Food and Radiation Biology (IFRB), Atomic Energy Research Establishment (AERE), Savar, Dhaka.Total viable bacterial count (TVBC) was done by the standard plate count method following the method described by Sharp and Lyles11. Nutrient agar (pH 7.0-7.4) was used to determine TVBC as well as for isolation purposes. Plates were incubated at 37ºC for 24 h and the count was expressed as colony forming unit per gram (cfu/g). Total viable coliform count (TCC) was done in the same way using MacConkey agar medium at 37ºC. mFC agar medium and staphylococcal agar media were used for total faecal coliform count and total staphylococcal count respectively. With a view to identify some selected isolates various morphological characteristics, biochemical and carbohydrate fermentation tests were performed. All the bacterial isolates were identified according to the Bergey’s Manual of Determinative Bacteriology12 and Manual for the Identification of Medical Bacteria13. Potato dextrose agar was used for total fungal count. The plates were incubated at 28º C and counts were recorded after 5 days of incubation. The fungal isolates were identified following theprocedures described by Gilman14, Raper and Fennel15 and Koneman et al.16.The fish samples were subjected to different radiation doses such as 0 (control), 2.5, 5 7.5 and 10 kGy of ionizing radiation at a dose rate of 1.25 Mrad/h from a 50,000 curie Co60 source (Gamma beam, 650, AECL, Canada) situated at the Institute of Food and Radiation Biology of AERE.All of the untreated control and irradiated samples were stored in low temperature (-20°C) in a deep freezer. The samples were then examined for microbiological qualities. Three replicas were studied for each of the sample. The bacteriological analyses were carried out before keeping the samples in the deep freeze and during storage once in a month up to six months.

Source of Information: Bangladesh J Microbiol, Volume 25, Number 2, December 2008, pp 105-109

Article Link (Online Journal):

Funding Source:

Total Budget (Tk.) :

Achievement/Findings:

The ranges of total viable bacterial count, total coliform count, total faecal coliform count and total staphylococcal count varied from 6.5 x 10⁴ to 1.0⁴ x 10⁵, 2 x 10² to 4.0 x 10^2,0 to 1 x 10²and 4.4 x 10⁴ to 3.8 x 10⁴cfu/g respectively, while the total fungal count was nil. Sixty-four bacterial isolates were identified including Staphylococcus (19%), Micrococcus (11%), Enterobacter (8%), Klebsiella (17%), Bacillus (19%), Escherichia (17%) and Pseudomonas (9%). To disinfect the microorganisms, the samples were irradiated at different doses (0-10.0 kGy) of gamma irradiation. Total coliform and total faecal coliform bacteria were inactivated below the detectable level at 2.5 kGy of irradiation. The number of total viable bacteria decreased by three logs when irradiated at 5.0 kGy and the number of Staphylococcus bacteria were eliminated completely after the irradiation dose of 5.0 kGy. During frozen storage, the total viable bacterial counts were gradually declined in all the samples. After six months of storage the bacterial counts were decreased about one log in all of the samples. It has been observed that combination treatments (irradiation and freezing) are more effective than the single treatment for eliminating the fish-borne bacteria.

Knowledge Management: Journal