In an effort to keep pace with the rapid growth of American mouthfuls, flatware manufacturer KitchenMaster announced yesterday the addition of a fifth tine to its line of dinner forks. 'These days, a traditional four-tined fork is just not enough to handle the quantities of food people shove down their throats,' said company spokesman Ken Krimstein, holding up a fork supporting six separate tortellini, two turkey sausages, and some mashed potatoes. 'To stay relevant to our customer base and bring back some of those who have given up on using utensils entirely, this was an adjustment we just had to make.' Krimstein added that the augmented forks would soon be followed by 25 percent deeper spoons and 3-gallon gravy boats. 