Journal of Pure and Applied MicrobiologyVol. 8 No. 6

Estimation of Microbial Load in High Temperature Thawed Buffalo Meat using Fluorescein Diacetate (FDA) Hydrolysis Assay

M.R. Vishnuraj1, G. Kandeepan1*, Vivek Shukla1, S.K. Mendiratta1, Arun T.R.2 and R.K. Agarwal2

1Division of Livestock Products Technology, Indian Veterinary Research Institute, Izatnagar, Bareilly - 243122, India. 2Division of Bacteriology and Mycology, Indian Veterinary Research Institute, Izatnagar, Bareilly - 243122, India

Received on 29 August 2014 and accepted on 25 November 2014



The aim of the study was to estimate the various microbial loads in different high temperature thawed frozen buffalo meat samples using fluorescein diacetate (FDA, 3', 6'-diacetyl-fluorescein) hydrolysis assay. Frozen buffalo meat (-18?1?C) samples was thawed at 25?1?C and 37?1?C for different durations in a temperature controlled incubator. All the samples were analyzed for various microbiological parameters using conventional plate count method and compared with FDA hydrolysis. Thawed samples were further stored at refrigeration temperature (4?1?C) and analyzed on alternate days. Significant (P<0.05) increase in FDA hydrolysis values were noticed after temperature abuse, where control sample showed an absorbance of 0.24?0.02 and most severely thawed sample showed a value of 0.48?0.02. Standard plate count (SPC), pseudomonas count, psychrophilic count and yeast-mold count increased significantly (P<0.05) after high temperature thawing. FDA hydrolysis showed significant (P<0.05) positive correlation with all the microbial parameters and highest degree of association was noticed between FDA and SPC (r = 0.97). Regression formula (Y = 0.08X-0.055, Y represents FDA, X represents SPC) was generated using FDA hydrolysis values and SPC value as dependent and independent variables respectively and found that predicted absorbance value of 0.5?0.05 was coinciding with upper limit of microbiological acceptance value (SPC) of log10 7 cfu/g for frozen fresh meat.

Keywords : FDA hydrolysis, buffalo meat, thawing, microbial load, correlation, refrigeration storage.