The discussion has been presented in two parts. The physical qualitative results have been taken up first. Table 1, which summarizes all the results, shows that except in the case of FGP2 and FGO, in all other cases, including C, the milk changes cooler. In the case of PWR the sample emits a foul smell and curdles, indicating a rapid growth of microorganisms as in C. So far as PWP and FGP1 are concerned, there is discolouration of the sample, which still retains its milky nature. The best results are obtained from FGP2 and FGO, where the sample still retains its milkiness, sweetness and liquidity.
Even though models PWR and PWP are both of wood, the difference in the behaviour of the milk samples between them shows that the pyramidal shape is more effective than the flat-roofed model. There is speculation that pyramidal shapes are effective in capturing cosmic radiation, which helps in arresting the growth of microorganisms. However, data to substantiate this is scanty. It will need a more detailed investigation to establish the veracity or otherwise of this speculation.
Models FGP1, FGP2 and FGO are made of fiber-reinforced plastic. However, the latter two show hardly any discolouration of the sample, whereas the former shows noticeable discolouration. The only difference between these models is their size, FGP1 being smaller than FGP2 and FGO.
The most interesting result is that for models FGP2 and FGO, which shows that the samples do not undergo any deterioration at all. These two models are both of fiber-reinforced plastic and both are pyramidal in shape. The only difference between them is that their bases are different, one of them being square and the other octagonal. Also, both of them are larger in volume than the other models used. This naturally leads to the question if there is any optimum size for which the pyramid is most effective. This will require a more detailed investigation before any definite conclusions can be drawn.
In order to decide whether these results are meaningful, a closer look at the quantitative results becomes necessary (Figs 2, 3 and 4). Figure 2 shows the data for Staphylococci, Fig. 3 for Bacillus and Fig. 4 for Corynebacteria. The growth in control is the highest for Staphylococci and Corynebacteria. The next highest is PWR, followed by PWP and FGP1, which is also the trend seen from the qualitative data. So far as Bacilli are concerned, all models except FGP2 and FGO appear to show the same trend.
Just as in the case of the qualitative results, the figures show that there is hardly any bacterial growth in the case of models FGP2 and FGO. Therefore, these two independent observations, qualitative and quantitative, support each other and lead to the conclusion that pyramidal structures do inhibit the growth of microorganisms.
