2.3.2. During fermentation
During sausage fermentation, cell counts of S. Typhimurium and Lactic
acid bacteria (LAB) were determined immediately after having
mixed the batter (day 0) and twice a day for the following three days.
At each sampling, a piece of sausage was withdrawn from the syringe
by pressing the piston, with the first 0.5 cm being discarded. A sausage
sample size of approximately 5 g was homogenized in 15 ml 0.9% NaCl
(wt/vol) by stomaching and prepared for bacterial enumeration. Cell
counts of S. Typhimurium were determined as described above for the
freezing experiments whereas LAB were determined using MRS agar
plates incubated aerobically at 25 °C for 2–3 d.
2.4. Statistical analysis
To approximate normal distribution, all viable counts were log10-
transformed. SAS Enterprise version 4.3 statistical software was used
to perform statistical analyses of the data. The response variable in the
statistical model was the S. Typhimurium counts in log10 (cfu g−1
). Effect
of bacterial growth phase (exponential/stationary) was tested for
each of 24 different combinations: two strains (DT12/DTU292), with
and without NaNO2 (0 ppm/100 ppm), with and without starter culture,
and with three frozen storage times (0, 7, N35 d) in three replications.
To test the significance variance analyses were performed using the
model PROC MIXED: