African Journal of
Food Science

  • Abbreviation: Afr. J. Food Sci.
  • Language: English
  • ISSN: 1996-0794
  • DOI: 10.5897/AJFS
  • Start Year: 2007
  • Published Articles: 823

Full Length Research Paper

Effect of irradiation on inoculated Salmonella parathyphi B and the colour of freeze-dried egg yolk

I. W. Ofosu1, F. B. Apea Bah2, A.  Adu-Gyamfi2*, G. M. Ankar-Brewoo1, I. Oduro1, W. O. Ellis1, M. Boakye-Wallace3 and A. Owusu-Marfo3
1Department of Food Science and Technology, College of Science, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana, 2Biotechnology and Nuclear Agriculture Research Institute, Ghana Atomic Energy Commission, Accra, Ghana. 3Department of Biochemistry and Biotechnology, College of Science, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
Email: [email protected]

  • Article Number - A9B03DF26005
  • Vol.4(9), pp. 603 - 607, September 2010
  •  Accepted: 20 July 2010
  •  Published: 30 September 2010


The effect of irradiation on the colour intensity of freeze-dried egg yolk samples (FDEY), from poultry birds given feed containing different concentrations of annatto extract was investigated. Concentrations of 1, 4, 7 and 10 % of annatto extracts were used in the poultry feed formulation and these were compared with feed containing no additive as well as one containing a commercial feed colourant, ‘carophyll yellow’. The FDEY samples coded R1, R2, R3, R4, C and CArespectively were inoculated with Salmonella parathyphi B and irradiated at doses of 0, 3 and 5 kGy with γ radiation from a 60Co source. Microbial counts and colour intensity were determined after irradiation. Results of the microbiological analysis showed that both 3 and 5 kGy doses were adequate in practically eliminatingSalmonella parathyphi B from the samples. However, it was observed from the colour analysis that irradiation at both 3 and 5 kGy doses caused significant (p < 0.0001) deterioration of the colour of the freeze-dried egg yolk samples.

Key words: Irradiation, Salmonella parathyphi B, colour intensity, freeze-dried egg yolk.

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