Mold growth in feed is influenced by many factors including moisture, temperature, oxygen and substrate. Among these factors moisture is the most critical. Mold growth gets ceased when moisture level in feed is below 10% and water activity is less than 0.6. Mold germinates and grows when feed moisture and water activity is above mentioned level. High humidity can also affect feed moisture and favours mold growth. At high humidity level, moisture get absorbed by feed at transportation and storage. Therefore, it is important to keep moisture at optimum level to avoid contamination during transportation and storage.