Optimizing Search For Food In Java Program

I have a java program where there are bacteria that have to eat the food spread for a map, I have to find a way to optimize the search for food, I put random at the beginning I have to try a better way...

protected void Move(){
int dx = (int)(Math.random()*3) - 1;
int dy = (int)(Math.random()*3) - 1;
if (x+dx >= 0 && x+dx<food.getWidth())
x += dx;
if (y+dy >= 0 && y+dy<food.getHeight())
y += dy;