However, the amount of yeast cells present was not greatly reduced by treatment with citric acid solution. Figure 4 shows the results of plating for mold using Petrifilms . Molds can grow and reproduce in very acidic conditions and some would grow optimally at the pH used for this experiment. In addition, mold spores are found in the air, on surfaces, and even on hands. This can help to explain the growth of mold from a product which showed no microbial growth after washing but did show microbial growth after the citric acid treatment.
Molds reproduce using sporulation.
The spores that are produced can survive more harsh environments and then germinate when conditions are favorable. No mold growth was observed in the finished salsa products, indicating that the heat treatment used for processing was sufficient to eliminate mold spores. Tables 1 and 2 summarize the results form these samplings. Table 1 shows that total processing time, cilantro residence time and total filling time were fairly consistent for for all control products. However, total processing time and cilantro residence time all decrease relative to the 14-gal. baseline time for the treated products.