الفهرس 
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Abstract
Bottled water is basically any potable water that is manufactured, distributed or offered for sale in any sealed container as food grade bottles, jugs and cans. Consumers may have various reasons for purchasing bottled water such as taste, convenience or fashion, but for many consumers, safety and potential health benefits are important considerations. Bottled water is generally not sterile and can contain bacteria not only from naturally occurring sources, but as well as those introduced during manufacturing, distribution and consumer handling, where the microbial quantity can evolve rapidly to high numbers during storage. The present study aimed to assess the indicators for the determination of the bacteriological quality of bottled water and to correlate the indicators of health hazards (TC and E.coli ) with those of compliance (P.aeruginosa and S.aureus) . This study was carried out on a total of 300 uncarbonated bottled water samples of 5 commercial brands produced in Egypt and were designated A, B, C, D and E. A 150 bottles were purchased unrefrigerated and the other 150 ones refrigerated. In addition 65 tap water samples were collected to compare their hygienic quality with that of bottled water. The bottled water samples were directly transferred to the laboratory and examined within 1-3 hours of purchasing. Each sample was vigorously shaken and was subjected to : 1- Total HPC determination: by standard pour plate method where 15 ml of molten plate count agar was transferred into each of two sterile petri-dishes containing one ml aliquots of each of the sample and/or chosen dilution that were then thoroughly mixed together. One set was incubated at 22°C for 72 hours and the other set was incubated at 37°C for 24 hours. The plates were counted using the Quebec colony counter and the total HPC was calculated per millimeter of the tested water sample. 2- Total coliform and E. coli MPN determination: Presumptive test was preformed by aseptically pipetting 50 ml of the sample into bottles each containing 50ml double strength LTB and 10ml of the sample into each of five replicate tubes each containing 10ml of double strength LTB. They were incubated at 37°C for 24-48 hours. Confirmed test was performed by subculturing LTB positive bottles and tubes into corresponding tubes of BGLBB that were incubated at 37°C for 24-48 hours, and tubes of EC broth that were incubated at 44.5°C for 24 hours in a waterbath. Each positive BGLBB tube was recorded and the TC MPN/ 100 ml of the water sample was calculated using MaCradey probability tables. Each positive EC tube was recorded and the FC MPN/100ml of the water sample was also calculated. The positive EC tubes were subcultured onto L-EMB agar plates and were incubated at 37°C for 24 hours. The suspected E. coli colonies were completely identified by Gram staining and biochemical tests (IMViC reactions) and the E.coli MPN/100ml of the water sample was calculated using the probability tables. 3-P. aeruginosa MPN determination: Presumptive test was performed by aseptically pipetting 10ml of the sample into each of five replicate tubes each containing 10ml double strength asparagine enrichment broth. Then 1ml and 0.1ml of the sample were inoculated into each of ten replicate tubes (five for each volume) each containing 10ml single strength broth respectively. They were incubated at 37°C for 24-48 hours. Confirmed test was performed by subculturing positive tubes onto acetamide agar slants that were incubated at 37°C for 24-36 hours. The suspected P.aeruginosa colonies were completely identified by Gram staining and biochemical tests and the P. aeruginosa MPN/100 ml of the water sample was calculated using the probability tables. 4-S. aureus MPN determination: Presumptive test was performed by aseptically pipetting 10ml of the sample into each of five replicate tubes each containing 10 ml double strength m-Staphylococcus broth. Then 1ml and 0.1ml of the sample were inoculated into each of ten replicate tubes each containing 10ml single strength broth respectively. They were incubated at 37°C for 24-48 hours. Confirmed test was performed by subculturing positive tubes onto LSM agar plates that were incubated at 37°C for 24-48 hours. The suspected S.aureus colonies were completely identified by Gram staining and biochemical tests and the S.aureus MPN/100ml was calculated using the probability tables. The 65 tap water samples were aseptically collected into sterile 250 ml bottles containing sodium thiosulphate. All tap water samples were subjected to HPC for the enumeration of total viable heterotrophic bacteria using the pour plate method and the MTD method for the enumeration of TC and E.coli and by the same procedures used for bottled water. The results of this study can be summarized as follows: 1- According to the Egyptian standards No.1589/2000, out of the 300 examined bottled water samples, 61.7 were acceptable while 38.3 were unacceptable.