The integrity of the samples obtained on the first 2 days
of sampling from Abattoir A was compromised. On Day
1 they (149 samples) were exposed to high air-shipment
temperatures (23.9C on arrival at the laboratory) and on
Day 2 the samples (120) were misplaced for 48 h by the
airline. Therefore, only the 123 pig carcases sampled on
Day 3 from Abattoir A were analysed (Table 1).
At Abattoir B on Day 3 the hot water temperature was
reduced from 81C to an average temperature of 76.5C
due to company concerns over slight superficial discolouration
reported in the boning rooms. In addition, the
chlorite concentration of SANOVA was reduced by
100 ppm/day over the 3 days from 1100 to 900 ppm in
an attempt to reduce the bleaching effect. Preliminary
analyses were performed to assess the effects of these
changes.1 The results (not presented) of these analyses
indicated that there was no significant difference in daily
mean levels of TVC, E. coli or Salmonella as a result of
changes to the hot water and SANOVA treatments.
Therefore, the changes to these treatments that occurred
over the sampling period were not considered in the subsequesequent analyses. At Abattoir B it was observed that 12
consecutive carcases from the Day 3 SANOVA treatment
group were contaminated with the same serovar of
Salmonella. It is suspected that a major contamination
event occurred and so the 50 · Day 3 SANOVA samples
were excluded from all analyses, leaving a total of 400
samples from Abattoir B.