from five randomly selected farm vats within each region. An effort was
made to avoid testing any supply more than once during the study. The
outcomewas that 297 sampleswere actually collected during the study:
Northland— 54 samples from53 suppliers;Waikato — 54 samples from
48 suppliers; Taranaki/Manawatu — 60 samples from 60 suppliers;
Canterbury — 64 samples from 64 suppliers; Southland — 65 samples
from 65 suppliers. Only seven farm vats were sampled more than once
during the entire study