Total Viable Count Of Samples Research Articles

Effects of processing on bacteriological, proximate, hydrocarbon content and organoleptic indices of Scomber scombrus

Effects of boiling, smoking and frying on the organoleptic quality, bacteriological count, proximate composition and total hydrocarbon contents of Scomber scombrus fish sold in Ikot Ekpene Metropolis were investigated. Fillets of fresh S. scombrus were made, and processed by smoking, boiling and frying methods. Portions of the fish sample were aliquoted, and used to carry out sensory evaluation, plating aliquots of diluents onto nutrient agar plates (for total viable count (TVC), and on Manitol Salt agar (for total staphylococcal count (TSC). Standard methods were used to determine moisture, ash, total lipids and crude protein contents. Total hydrocarbon content was determined by toluene extraction and measurement of absorbance of filtrate spectrophotometrically. Sensory quality obtained using smoke-drying and frying methods scored significantly higher than that of boiling and the control (p<0.05). TVC of samples were lower than in the control fish sample after processing, increasing over the 4-day period, although negligible when compared to the control. TVC were lowest in samples processed by frying. TSC decreased in all fish samples after processing, except in the control fish sample. Fried Scomber scombrus samples also showed no trace of S. aureus. Moisture, lipid, crude protein and ash contents of control S. scombrus were 68.78±1.02, 2.03±0.11, 20.14±0.06 and 0.09±0.32 respectively. The changes in moisture, lipid, crude protein and ash contents were statistically significant (P<0.05) in processed fish samples. Total hydrocarbon content also increased in processed fish; 2.914±0.005 for smoke-dried, 2.168±0.001 for fried and 1.538±0.009 for boiled, as against 1.412±0.011 in the control sample. Overall bacteriological quality indices, the proximate content and total hydrocarbon contents of samples demonstrated frying and smoking as preferable processing methods for Scomber scombrus.

INFLUENCE MATURATION OF VEAL ON THE MICROBIOLOGICAL AND PHYSICAL INDICATORS

The aim of the present study was to evaluate microbial and pH changes in veal meat during maturation. Total viable counts, coliform bacteria and pH changes in chilling meat were evaluated after 24 hours, 7 days and 14 days of meat maturation. There were analysed 8 samples of veal meeat. Results of microbiological analysis were compared with Commission regulation (EC) No 2073/2005 on microbiological criteria for foodstuffs. Total viable counts (TVC) in samples after 24 hours of chilling ranged from 2.02 log CFU.cm-to 4.21 log CFU.cm-2 (1.64 . 104 CFU.cm-2). The average number of TVC after 24 hours of meat maturation was 3.27 log CFU.cm-2, coliform bacteria (CB) after 24 hours were lower than than 1 log cfu.cm-2 in five samples, and the highest number of coliform bacteria was 1.65 log cfu.cm-2, average number of CB was 1.13 log cfu.cm-2. pH values in samples after 24 hours of maturation were in range from 6.6 to 7.0, average pH value was 6.8. TVC in samples after 7 days of chilling ranged from 3.09 log CFU.cm-2 to 4.01 log CFU.cm-2, the average number of TVC after 7 days of storage was 3.39 log CFU.cm-2. CB after 7 days of meat maturation were lower than 1 log CFU cm-2 in three samples, the highest value of CB was 2.07 log CFU cm-2, the average value of CB in samples after 7 days of meat chilling was 1.03 log CFU cm-2. pH values of meat after 7 days of maturation ranged from 5.5 to 6.1. The average pH value of samples after 7 days of storage was 5.73 pH values of meat after 14 days of maturation ranged from 6.0 to 6.4. The average pH value of samples after 14 days of storage was 6.16.

Effect of an argon-containing packaging atmosphere on the quality of fresh pork sausages during refrigerated storage

The effects of modified atmosphere packaging (MAP) with commercial gas mixtures made up of either CO 2 and argon or CO 2 and nitrogen on the microbiological and physico-chemical characteristics of fresh pork sausages during refrigerated storage were studied and the results compared with vacuum and over-wrap packaging. The presence of argon in the mixture of gases barely affected the growth of enterobacteria, which were at their lowest levels ( P < 0.05) at the end of the preservation period. MAP with argon did not affect ( P > 0.05) lactic acid bacteria or total viable counts in samples with N 2. The biogenic amine levels in all the samples remained low during storage with the exception of spermidine and spermine. There were no significant differences between the two lots in MAP respecting color parameters. MAP with argon and CO 2 had a beneficial effect on sensorial evaluation during the 28 days storage period, when compared with that of the control, which was rejected after 11 days of storage.

Microbiological Quality of Local Market Vended Freshly Squeezed Fruit Juices in Dhaka City, Bangladesh

Freshly squeezed or freshly prepared fruit juices sold by local market vendors in Dhaka city were analyzed for the microbiological quality. Total viable bacterial counts, fungal counts, total coliform, faecal coliform and the presence of pathogenic microorganisms such as E. coli, Bacillus cereus, Staphylococcus aureus, Salmonella, Streptococcus were analyzed by standard methods. The total viable count of samples ranged from 3.00×102 to 9.60×108 and fungal counts ranged from 1.00×102 to 8.05×104. Out of 114 freshly prepared fruit juices samples collected 113 samples (99%) showed the presence of coliform and E. coli. The other bacteria like B. cereus, Staphylococcus aureus, Salmonella, Streptococcus were found in 64.91%, 6.14%, 7.89% and (5.26%) of the tested samples. The number and type of microorganisms recovered from the freshly squeezed fruit juices made them unsafe for drinking. It was concluded that due to unhygienic fruit handling in the unsanitary environmental conditions under which the vendors operate the juices become contaminated with harmful bacteria. The results of this study demonstrate the unhygienic quality of popular types of market vended freshly squeezed fruit juices and their risk to the consumers. Key Words: Fruit juices; Microorganisms; Contamination; E. coli; Microbiological quality standards. DOI: 10.3329/bjsir.v44i4.4591 Bangladesh J. Sci. Ind. Res. 44(4), 421-424, 2009