Dahi is yoghurt like fermented dairy products available in Bangladesh made by traditional ways from raw milk. The aim of the present study was to check and compare the present quality status of the market dahi in reference to laboratory made dahi. For this, dahi was prepared in the laboratory (A) and collected from Kishoregonj district (B), Gazipur district (C), Bogra district (D) and Dhaka district (E and F). Consumer acceptance quality was judged on 100 point by a judge panel and chemical and microbiological quality test were done by established methods. ‘A’ type dahi was superior followed by E, D, F, B and C considering the consumer acceptance quality parameter. From chemical test, it appears that, B possess the lowest pH (3.75 ± 0.05) and highest was in C (4.46 ± 0.15). Total solids content of F type dahi (318.40 ± 4.44 g/kg) was highest and fat (52.00 ± 2.00 g/kg), protein (44.33 ± 2.00 g/kg) and ash (10.76 ± 0.31 g/kg) content were also higher in F type dahi. E and A type dahi were also with considerable figure in chemical quality parameter. Dahi B was inferior in respect of microbiological quality- total viable count (TVC) (× 105 cfu/ml) content was 94.00 ± 4.58, yeast (cfu/ml) content was 183.33 ± 15.28 and mold (cfu/ml) content was 53.33 ± 15.28. The TVC (× 105 cfu/ml), yeast (cfu/ml) and mold (cfu/ml) content of A type dahi were 39.67 ± 4.51, 50.00 ± 10.00 and 20.00 ± 10.00, respectively. Considering all the three major quality aspects dahi A was superior than others followed by F, D, E, C and B.

This study was conducted to develop a model for describing the effect of storage temperature (4, 10, 15, 20, 25, 30 and 35℃) on the growth of Escherichia coli O157 : H7 in ready-to-eat (RTE) lettuce treated with or without (control) alkaline electrolyzed water (AIEW). The growth curves were well fitted with the Gompertz equation, which was used to determine the specific growth rate (SGR) and lag time (LT) of E. coli O157 : H7 (R2 = 0.994). Results showed that the obtained SGR and LT were dependent on the storage temperature. The growth rate increased with increasing temperature from 4 to 35℃. The square root models were used to evaluate the effect of storage temperature on the growth of E. coli O157 : H7 in lettuce samples treated without or with AIEW. The coefficient of determination (R2), adjusted determination coefficient (R2 Adj), and mean square error (MSE) were employed to validate the established models. It showed that R2 and R2 Adj were close to 1 (> 0.93), and MSE calculated from models of untreated and treated lettuce were 0.031 and 0.025, respectively. The results demonstrated that the overall predictions of the growth of E. coli O157 : H7 agreed with the observed data.

The study was conducted to evaluate the effect of drying, curing and freezing on the quality of beef. Three types of dried (without salt = T1, with salt = T2 and salt + spices = T3); three types of cured (salt curing = T4, sugar curing = T5 and brine curing = T6) and three types of frozen beef (0℃ = T7, -10℃ = T8 and -20℃ = T9) were analyzed at different time intervals up to the period of 180 d. Parameters studied were protein, fat, ash, color and cooking loss of beef. All the chemical constituents (protein, fat and ash) were decreased gradually up to 120 d. The decreasing trend was observed rapid after 120 d up to 180 d of preservation. Highest protein loss was found in T7 (11.1%) and the lowest protein loss was found in T6 (3.85%) in 180 d preservation and significant (p < 0.01) differences were observed among the different preservation methods. Highest fat loss was observed in T6 (7.62%) and the lowest fat loss was observed in T2 (3.18%) and the differences were also significant (p < 0.05) among different methods during the experimental period. Spices dried beef showed a brighter color than others and cured beef showed brown color and the intensity of color was reduced gradually with the increasing of storage period. T9 showed the lowest cooking loss among 3 treatments of frozen beef and the differences also significant (p < 0.01) up to 180 d. It might be stated that sugar curing (T5) and spices drying (T3) would be the useful technique of meat preservation in rural areas and freezing (T9) would be used in large scale preservation at urban areas.

The statistics probability approach for microbial risk assessment (MRA) has been recognized as an efficient method because this probability approach, which can be presented the diversity, variability, and uncertainty for the environmental factors of food processing, provide better realistic results than point estimate. This study was conducted to determine of probability statistics for the environmental factors of the pork-cutting processing i.e. the processing time, the pork meat temperature, and processing room temperature etc. As the input parameters for the MRA, triangular distribution and normal distribution were selected as an efficient probability distribution model, these distributions were analyzed by the simulation. The simulation results showed the processing time estimated 53 min as mean (5% - 22 min and 95% - 98 min), pork meat temperature estimated 4.83 ℃ as mean (5% - 2.25 ℃ and 95% - 7.12 ℃, 48.78% exceed 5 ℃), and processing room temperature estimated 17 ℃ as mean (5% - 10.92 ℃ and 95% - 22.56 ℃, 71.178% exceed 15 ℃).