Kent a. Physical-chemical quality of processing water. The results were very similar to those observed in packinghouse 2. The physical-chemical variable most affected was turbidity, since it far exceeded the critical value of the Standard (Table 7). The source water was the only one below the critical level. However, it was observed in the processing water for fruit washing that at the end of a wash cycle of 1,200 boxes the turbidity value exceeded by more than 50 times the critical value of the Standard and the pH became very acidic. The reason for this difference may be that in this packinghouse, they use peroxyacetic acid as a disinfectant, but the same mistake is made in washing too many boxes with the same water. In addition, in hydrothermal tanks water with 5, 9 or 19 baskets of use (hydrothermal 1, hydrothermal 2 and hydrothermal 3, respectively), a tendency to increase the turbidity value was observed as the number of processed baskets increased, to exceed four times the critical value of the Standard. As it is known, the hydrothermal treatment time lasts up to 110 min (depending on the size of the fruit), if the degree of turbidity is very high, the potential risk of contamination of the fruits is too high. The suggestion is to avoid reaching levels that far exceed the critical level established by the Standard. The recommendation is to do more frequent changes of the processing water, in washing, hydrothermal and hydrocooling. For this packinghouse, the hydrocooling water was still within the tolerable limits. On the other hand, another variable out of range was the total hardness of the water, which increased significantly in the final and hydrothermal washing stage 3. This may be influenced by the water source, the use of peroxyacetic acid and the accumulation of salts of magnesium and calcium. Table 7. Physical-chemical composition of the processing water in exporting mango packinghouses during a scanning. Treatment pH Turbidity (UNT) Total hardness (mg/L) E. C. (dS m-1) Sulfates (mg/L) Chloride (mg/L) Source 7.8 1.0 165.7 1.0 3.6 113.2 Initial washing 6.9 9.7 427.9 1.0 11.4 114.6 Final washing 5.8 265.3 959.3 1.2 78.7 112.1 Hydrothermal 1 7.7 8.7 459.6 1.1 11.4 150.5 Hydrothermal 2 7.5 13.7 411.5 1.1 16.4 119.8 Hydrothermal 3 7.7 20.0 632.7 1.3 18.1 184.8 Hydrocooling 7.9 4.3 215.2 1.1 16.8 100.2 Critical values 6.5 - 8.5 < 5.0 500.0 > 2.0 400.0 250.0 Figure 8 illustrates the degree of turbidity of the processing water in the different stages of h...
