How solar cooking with a solar box cooker led to the opportunity to bring world-class water testing to communities, leading to an understanding of the relationship between fecal contamination of drinking water sources and waterborne disease.
Date(s): 1987-2003. Album by Bob Metcalf. Photos by Bob Metcalf. 1 - 112 of 112 Total. 2056 Visits.
1 The presence of the bacterium Escherichia coli indicates recent fecal contamination of water.
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3 First step: gas from lactose broth at 35°C.
4 2nd step: 2nd lactose broth incubated at 44.5°C +/- 0.2°C. Gas produced by 'thermotolerant coliforms'
5 Most strains of E. coli produce gas at 44.5°C
6 But so do environmental coliform bacteria like this Klebsiella sp. The thermotolerant coliform test is not specific for E. coli.
7 The burden of collecting and using firewood to cook food for ~2.5 billion people in developing countries
8 Tree cutting leads to deforestation and land degradation
9 Barbara Kerr and Sherry Cole developed a practical solar box cooker in 1976.
10 Regular solar cooking in Sacramento since 1978.
11 Solar cooking in Sacramento, California, June, 1991
12 Bolivia, 1987, teaching how to build and use a solar box cooker. No simple water test available.
13 Guatemala, January, 1998.
14 Built solar box cookers but no simple water test available.
15 In 1988, a new approach to test for E. coli is announced. Colilert, a defined substrate test
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17 Colilert was available as a dry powder in glass tubes to test 10 ml of water. Made by Access Medical Systems, CT.
18 IDEXX took over production of Colilert from ACCESS in 1993.
19 January, 1989, Sierra Leone. With Colilert, water testing could be included with building solar box cookers.
20 First solar box cooker made in Sierra Leone
21 Cake baked in solar box cooker for 2 hours
22 Fish soup & rice solar cooked
23 Distribution of Colilert tubes to 41 workshop participants to sample home water source.
24 Tubes can be incubated next to one's body to obtain next day results.
25 Body incubation of Colilert tubes
26 Next day results.
27 Clear = no coliform bacteria. Yellow (ONPG+) = coliform bacteria present, possibly E. coli
28 Shine a long-wavelenth UV light on tubes. Blue fluorescence = MUG (+), E. coli is present (right tube). MUG (-), E. coli not present.
29 39 of 41 tubes were ONPG + (yellow), coliform bacteria present, perhaps E. coli.
30 26 of 41 samples were MUG (+), indicating the presence of E. coli.
40 Somali women returning from 8 hour journey to collect wood, Dadaab refugee camp, Kenya, 1995
41 Refugee children returning with sticks after a long journey.
42 Introduction of the simple Cookit solar cooker. Foods cooked inside clear plastic bags.
43 Cookit among refugee dwellings.
44 Refugee family with Cookit.
45 Solar cooking works!
46 Dadaab Refugee Camp, Tanzania, 1995.Testing borehole water with Colilert. ONPG (+), MUG (-)Low disease risk
47 In 1995, E. coli Count Petrifilms were available to test 1 ml.
48 To use Petrifilm, label sample source and time
49 Add 1 ml of water sample to nutrient circle
50 Use flat side of plastic spreader to gently distribute 1 ml over entire circle
51 Petriflms covered with firm cardboard enables incubation on one's body. Invisible bacteria to develop into visible colonies in 12-16 hours.
52 Results usually in 12-18 hr. E. coli = blue colonies with gas. Coliforms from environment = red with gas.
53 First use of E. coli Count Petrifilm on raw camel milk in Dadaab refugee camp, 1995
54 Inoculated Petrifilms with 1 ml. Incubated on body between cardboard pieces to obtain overnight results.
55 Next day results. > 200 E. coli/ml before pasteurization.
56 Colilert and Petrifilm tests correlate with risk of disease, WHO Guidelines for Drinking Water Quality, 2nd Edition.
57 Colilert and Petrifilm results also correlate with MSF treatment guidelines in emergencies.
58 Students at California State University, Sacramento, who contributed to water pasteurization work
59 Heating water to 65°C will pasteurize water and make it safe to drink.
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61 Water Pasteurization Indicator (WAPI). When water reaches 65°C (149°F), wax melts and falls to the bottom. Water is pasteurized.
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63 Article on Cookit and WAPI to pasteurize water, 1999
64 Water Pasteurization Indicator used by Dadaab refugees who received Cookit solar cookers, 1995.
65 Fuelwood problems in Meatu District, Tanzania, 2000
66 Water source, Meatu District, Tanzania
67 Sampling water source, Meatu District
68 Removing water sample for Colilert and Petrifilm tests, Meatu District
69 Water source, Meatu District
70 Water seller collecting water in Meatu District
71 Components of the Portable Microbiology Laboratory to test water in Meatu District
72 Materials for 25 water tests in gallon-sized plastic bag to make a Portable Microbiology Laboratory.
73 UN-Habitat Booklet on Water Testing, 2010
74 Any table becomes a laboratory to test village water sources
75 Testing numerous water sources in Meatu District, 2000
76 Results from one village. 1 ml removed from Colilert tube for separate incubation.
77 Results of Meatu water tests.
78 Village chiefs and village health workers in 3 day workshop, 2001.
79 Demystifying microbiology, teaching community about bacteria and water testing
80 Topics covered include bacteria size, growth, E. coli as indicator, Colilert & Petrifilm tests, WHO disease risk guidelines
81 Next day results. Most local water sources from dry riverbed were high/very high risk.
82 Village chief knows that MUG+ Colilert means that E. coli was in the town's river water source, unsafe water
83 Health worker finds >10 E. coli on Petrifilm, a very high risk of disease
84 Water testing workshop for Saka Saka village, 2002. Boniphace translates into Kiswahili.
85 Two water sources in Saka Saka. From a pump (green bucket) and an open stream (yellow bucket).
86 Adults will sample either pump or stream water
87 Mixing inoculated Colilert tubes, to incubate overnight
88 Inoculating Petrifilms
89 Inoculating Petrifilms
90 Next morning demonstration of solar cooking, solar water pasteurization
91 Read results: Pump water yellow, MUG -, no E. coli. Stream yellow and MUG+, E. coli present.
92 Examining Petrifilms
93 Petrifilm results are clear.
94 Stream water (front) with ~100 E. coli colonies on each Petrifilm, very high disease risk. Pump water (back) with environmental coliforms,no E. coli, low disease risk.
95 All villagers see results of grossly contaminated stream water, no E. coli contamination of pump water.
96 Solar cooked rice in 2 hr
97 Boniphace shows wax melted in Water Pasteurization Indicator (WAPI), water safe to drink
98 Providing a year's supply of water testing materials to Saka Saka health workers to monitor pump water
99 After only an afternoon and a morning session, Saka Saka village understands the microbiology of water testing.
100 Competence in water microbiology is established in the village.
101 Guest House (hotel) in Meatu District
102 River water provided for guests
103 After testing river water, collect for solar pasteurization
104 Heating river water in Cookit to pasteurize
105 Temperature >60°C in 2 hours
106 WAPI wax melted, water is pasteurized
107 Evidence-based microbiology that contaminated water has been pasteurized.
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109 Poster at 2001 American Society for Microbiology Annual Meeting
110 Poster at 2003 American Society for Microbiology Annual Meeting
111 Poster at 2005 American Society for Microbiology Annual Meeting
