Agriculture Reference
In-Depth Information
markets in Accra have a drainage system and only 26 per cent have toilet
facilities, while 34 per cent are connected to pipe-borne water (Nyanteng,
1998). The results suggest that the initial on-farm contamination is so high
that it overshadows any possible post-harvest contamination.
Significantly higher levels of FCs in well- and stream-water irrigated
lettuce were recorded in Kumasi during the rainy season than in the dry
season. A similar but non-significant trend was observed in Accra. In fact, it
might be expected that in the rainy season, when contamination of the
irrigation water is more diluted and farmers irrigate less, FC population on
lettuce at the farm gate would be lower than in the dry season. Another
observation was that crop contamination also takes place under irrigation
with piped water. One reason could be that poultry manure does not dry
suciently; another reason is that splashes from the soil during heavy rains
may contain pathogens from already contaminated soil (Bastos, 1992).
Phase IV: Field trial
The results of the field trial (Amoah et al, 2005) confirmed that, even at the
farm level, wastewater is only one of several sources of crop contamination.
The soil and poultry manure were identified as other sources of
microbiological contamination, although wastewater is the most significant
one. The need to reduce the potential health risks resulting from FC and
helminth contamination of urban and peri-urban vegetables thus requires a
more holistic approach rather than concentrating solely on wastewater.
Health risk reduction
The study indicates it is crucial to reduce health risks associated with the
consumption of contaminated lettuce at the farm level through good
agricultural practices. This, however, is not as easy as is often suggested.
Farmers might not be able to make changes to irrigation methods, timing and
crops (Drechsel et al, 2002). Therefore, other options are under investigation
under the Challenge Program on Water for Food (CPWF), a major
international effort being conducted by the Consultative Group on
International Agricultural Research (CGIAR). Although first trials by IWMI
show that the on-farm contamination levels can be reduced through minor
changes in practices, it is unlikely that contamination can be minimized below
the threshold for safe consumption, as data from the use of piped water show.
Thus, it will always be necessary to wash the crops, in addition to improving
farming practices.
The last stage in the production-consumption chain, where food for
consumption or fast-food for street sales is prepared, appears to be a good
entry point for improving hygiene. This is because awareness for food safety
is generally high at this point. Also, more than 90 per cent of the food vendors
and consumers wash salad. However, individual methods vary widely and
seldom meet the required standards (Amoah, in press). Moreover, consumers
reduce health risks by trusting only food vendors with neat appearance and
