S Afrin
Department of Animal Science, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh
MM Hossain
Department of Animal Science, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh
M Khan
Department of Animal Science, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh
MD Hossain
Department of Animal Science, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh
Beef, Microbial assessment, Contamination, Storage quality, Local market
Animal Science laboratory, Department of Animal Science, Bangladesh Agricultural University (BAU), Mymensingh
Animal Health and Management
Experimental site and period- The experiment was conducted in the Animal Science laboratory under the department of Animal Science, Bangladesh Agricultural University (BAU), Mymensingh, Bangladesh. The experiment was conducted from July to December, 2014. Sample collection The samples of beef were collected from the Bangladesh Agricultural University sheshmore market, K.R market , Kewatkhali market and Mymensingh sadar market. A quantity of 1000 ±30 g of beef samples were collected from each market. The samples were collected from thigh region of bull without the fat, ligaments, bone and tendons. Meat sample were collected in sterilized bags, level the bags and stored in -20°C for the pending analysis. Experimental design There were three treatments in this study. These were T0= 0 hr, T1= 2 hrs, T2= 5 hrs that is the bacterial counts were taken at 0, 2, and 5 hours after the collection of the sample from each location. For microbial assessment total viable count (TVC) , total coliform count (TCC), and total yeast-mould count (TYMC) were undertaken. Media and reagents- For the bacteriological analysis the three used media were plate count agar (PCA), MacConkey agar (MA) and potato dextrose agar (PDA).To prepare the PCA and MA 13.13g PCA and 33.49g MA agar were dissolved in 750 ml and 650 ml of cold distilled water respectively in two separate conical flasks and heated to boiling for dissolving the ingredients completely. The media was sterilized at 121°C for 15 minutes in an autoclave. The final reaction was adjusted to pH 7.0±0.1. The agar was then ready for pouring. In case of PDA, 25.35 g of previously peeled and sliced potato were taken in 650 ml of distilled water in a conical flask and boiling for dissolving the ingredients completely. After boiling, sieving had done through clean cheesecloth. 5.76 g peptone agar was dissolved in 576 ml distilled water and heated up to boiling to dissolve the ingredients pouring, the media was kept in boiling water bath at 45 °C. Experimental equipments- Different types of glassware and equipments were used during the period of the experiment. These were: test tubes, petrideshes, conical flask, pipette (1 ml, 5ml, 10ml and 25ml capacities), glass rod spreader, test tube stand, mortar and pestle, whirly mixture machine, blender machine, water bath, incubator, refrigerator, sterilizing instruments, hot air oven, ice boxes, electronic balance. Preparation of sample for microbial studies- Each of the beef samples were thoroughly and uniformly macerated in a mechanical blender using a sterile diluents ( 0.1% peptone water) as per recommendation of International Organization for Standardization (ISO ,1995). A quantity of 30g of the minced meat sample were taken aseptically transferred into a sterile container containing 90 ml of 0.1% peptone water. Homogenized suspensions were made in a sterile blender. Thus 1:10 dilution of the samples was obtained. Later on using whirly mixture machine different serial dilutions ranging from 10-2 and 10-6 will be prepared according to the instruction of the standard method (ISO, 1995). Enumeration of Total Viable Count (TVC)- For the determination of TVC, 0.1 ml of each ten-fold dilution was transferred and spread on triplicate PCA using a sterile pipette for each dilution. The diluted samples were spread as quickly as possible on the surface of the plate with a sterile glass spreader. One sterile spreader was used for each plate. The plates were then kept in an incubator at 35°C for 2448 hours. Following incubation, plates exhibiting 30-300 colonies were counted. Colonies were counted with the aid of a colony counter. The average number of colonies in a particular dilution were multiplied by the dilution factor to obtain the Total Viable Count. The TVC was calculated according to ISO (1995). Enumeration of Total Coliform Count (TCC)- For the determination of TCC, 0.1 ml of each ten-fold dilution was transferred and spread on triplicate MA agar using a sterile pipette for each dilution . The diluted samples were spread as quickly as possible on the surface of the plate with a sterile glass spreader. The plates were kept in an incubator at 35°C for 2448 hours. Following incubation, plates exhibiting 30-300 colonies were counted with the aid of a colony counter. The average numbers of colonies in a particular dilution were multiplied by the dilution factor to obtain the TCC. The TCC were calculated according to ISO (1995). Enumeration of Total Yeast and Mould Count (TYMC) For the determination of TYMC, 0.1 ml of each ten-fold dilution was transferred and spread on triplicate PDA agar using a sterile pipette for each dilution. The diluted samples were spread as quickly as possible on the surface of the plate with a sterile glass spreader. The plates were kept in an incubator at 25°C for 48-72 hours. Following incubation, plates exhibiting 30-300 colonies were counted by colony counter. The average numbers of colonies in a particular dilution were multiplied by the dilution factor to obtain the TYMC. The TYMC were calculated according to ISO (1995). All the results of microbial count were expressed as the number of organisms or colony forming units per gram (cfu/g) of meat sample. Then results were calculated into log value. Statistical analysis All the average, means and standard deviations were calculated through Microsoft Excel 2010 Data analysis tool pack. SPSS 17.0 is used to determine the correlation among different microbial counts. One way ANOVA from Microsoft Excel 2010 Data analysis tool pack was used to calculate P value. Means were considered significantly different for P<0.05. Data are shown as mean ± SD.
Bang. J. Anim. Sci. 2017. 46 (4):244-248
Journal