Here the microbiological safety hazards are the presence of pathogens
or their toxins. The final product has a pH of 3.9–4.2 and, stored at chill
temperatures, it will not permit pathogen growth and will in fact have a
moderate lethal effect depending on the pathogen considered. The
properties of the product will however have no effect on preformed
toxins introduced during processing.
Control of pathogens in the product is obtained by pasteurization of
the milk and by ensuring a satisfactory fermentation to give pHo4.3 so
CCPs will be located at points critical to achieving these goals. For
example, incoming milk must be tested for antibiotic residues which may
inhibit starter-culture activity, and the time and temperature of heat
treatment, and factors governing the fermentation such as temperature
and starter composition, must all be strictly controlled and monitored.
Figure 11.11 Flow diagram and CCPs for yoghurt with fruit or nut puree. CCP, critical
control point; O, major contamination source
(Reproduced with permission from Shapton and Shapton (1991))
Chapter 11 433