Our forefathers have left us with a trove of religious practices which are an integral part of the Indian culture. However, somewhere we have forgotten these early practices that have a purpose of upholding them. One of these practices includes sprinkling water in a sparkling method around their plate or banana leaf thrice.
This practice is still prevalent in most sectors of southern and northern India. While the common belief is that it is a method of asking blessings from the deities.
But there is another outlook of doing this, that is

Spiritual Significance
Sprinkling water around food is believed to indicate an 'offering to god and thanking him for blessing us with food to eat.' In fact, some people keep some part of the food aside as an offering to the gods, who govern the elements of nature before starting the meal. This practice is known as chitrahuti.

Logical Significance
This ancient practice is believed to have started by sages in olden times, who spent most of their lives living in forest areas or in raw houses, where the floors weren't concrete on which they sat and ate food. Moreover, the food was mostly served with banana plantains. The food was prone to be exposed to the muddy floor making it unhealthy; which is why water was sprinkled around the plates to settle the mud or dust particles down.

Another reason may be that sprinkling water was also a great way to keep insects and pests at bay, especially at night when there is barely any light. It is said that ants or any insect cannot cross or tread upon the water.

Other Theories
Some believe that Indian food contains a lot of spicy or acidic content. Thus, sprinkling small quantity of water on and around food could help act as a neutralizer.
Another theory is that south Indian food contains a lot of rice and starch content. Therefore, sprinkling water could dilute the starch content and make it easier to digest.