Care was taken when handling aphids to avoid cross-contamination between different clones.
The environmental investigation supported this finding, identifying poor food handling practices during preparation of the custard that might have resulted in cross-contamination.
Another important application of species diagnosis is the purity control of the strains used to prepare live vaccines, thus avoiding potential cross-contamination.
Additionally, some cases may have resulted from secondary transmission or possibly cross-contamination at the retail outlet.
Laboratory cross-contamination was unlikely because the initial subtyping was done in different laboratories.
Most outbreaks were linked to cross-contamination and inadequate heat treatment.
The cross-contamination resulting from the overproduction was probably the main contributory factor of the outbreak.
The lung or air sac, heart, liver, spleen, kidney and intestine were collected using different sets of instruments in order to prevent possible cross-contamination.
