A study to examine the effect of depth and distance of the boreholes from the septic tank on physico-chemical parameters of the borehole water consumed in Dar Es Salaam, Tanzania was conducted. Samples were collected from 48 boreholes in Ilala, Kinondoni and Temeke districts and subjected to pH, B.O.D (Biological Oxygen Demand), total hardness, copper and lead analyses in relation to safety and quality levels set by WHO and TBS. Analysis by R-statistics indicated that pH and B.O.D significantly (p<0.05) decreased as the depth of borehole increased, whereas total hardness was significantly (p<0.05) higher in very deep boreholes than the other heights. Total hardness and pH were not significantly (p>0.05) affected by distance between septic tank and borehole and the B.O.D levels were significantly higher in the borehole water situated near the septic tank than those which were Journal of Food Studies ISSN 2377-1356 2018 far. Based on the physico-chemical characteristics of water, 25% of the samples did not comply with WHO and TBS specification limits while 75% complied, most of which had shallow depths and were situated near the septic tank. It may thus be concluded that both the distance and the depth between septic tank and borehole influenced physico-chemical characteristics of water.

Proteolysis of milk during storage by two strains of Pseudomonas NCIMB 702085 (414) and NCIMB 701274 (416) was investigated using the Urea PAGE method. Pseudomonas fluorescens enzymes were also extracted and purified by dialysis before inoculation into UHT skim milk in an attempt to partially purify the enzyme. Results showed that dialysis removed some peptides and amino acids which would interfere with the assay procedure. The method also confirmed that Pseudomonas fluorescens NCIMB 701274 (416) was more proteolytic than Pseudomonas NCIMB 702085 (414). Thus, Urea PAGE is a useful method for monitoring proteolysis in milk by Pseudomonas fluorescens.

A study was conducted to determine the influence of ionic calcium on gelation and proteolysis in milk. Raw milk was heated to 142 °C for 2s followed by cooling to 5 °C to make UHT milk. Two sequestering agents, Trisodium citrate (TSC) and Sodium hexametaphosphate (SHMP) were added at 0.04 -0.08% (w/v) to the processed UHT milk to reduce the ionic calcium levels. Proteolysis and gelation were induced by addition of trypsin (248 BAEE units), 0.03% (v/v) chymosin and 10 6 cfu/mL Pseudomonas fluorescens NCIMB 702085 (Ps. fl. 416) to UHT milk. Samples were stored at 25 °C for 2½ weeks to monitor gelation and Ca 2+ and some were incubated at 37 °C for 2h to monitor proteolysis. SHMP reduced more Ca 2+ than TSC. Ca 2+ reduction was accompanied by an increase in pH, most evident with TSC at 25 °C. Gelation was not observed in samples inoculated with Ps. fl. 416 (with sequestering agents) even after 9 days of storage, suggesting the importance of calcium in gelation. Chymosin treated samples gelled on day 0, whereas other samples gelled after 4 days. Trypsin increased Ca 2+ to levels higher than originally present in control UHT skim milk. Although in the current study, proteolysis was higher in samples inoculated with Pseudomonas fluorescens 416, no clear relationship was established between proteolysis and gelation in UHT milk. This observation Journal of Food Studies