YOU START a kid out on cream cheese and jelly sandwiches, watch him scoop up onion potato chip dip in his teens and in his adult life turn to health-food-no-additive cheese.

This is what happens when they grow up to be tasters and try 20 different brands of cream cheese on a single, creamy rich day.

They choose as number one, Philadelphia brand, which never came from Philadelphia but from South Edmenston, N.Y. As second favorite they select whipped cheese with onion and as third place favorite, Regent's of California cream cheese with no additives.

We found the 20 different flavored and plain cream cheeses available at neighborhood markets, bought them and conducted the taste test reported on here. The brands are listed in order of preference:

1. Kraft Philadelphia Brand: Good dairy flavor; creamy; traditional cream cheese taste.

2. Kraft Whipped with onions: Onion-scallion flavor; fluffy

3. Regent's: Neuter, bland but creamy; good texture.

4. Regent's with scallions: All tasters thought it tasted like fresh chives, garlic or onions, not scallions; tart, dairy flavor.

5. Le Midi with garlic: Intersting bite; buttery; musky; lively; oniony.

6. Imported Danish with herbs (no brand name): The tasters were very confused on this one. Good fresh herb flavor; tomato taste; pimento; buttery texture.

7. Safeway's Lucerne: Gummy; plastic, smooth, but too subtle; dusty, dairy flavor; I'd rather be in Philadelphia than here.

8. Kraft Whipped with chives: Strong dried chive flavor, slightly sweet.

9. Old Fashioned Natural of California: Lacks flavor; heavy texture; slightly tangy.

10. Kraft Whippped with salmon: Fishy, crab taste; paprika flavor. THE SECOND DIVISION, 11 TO 20

Zausner's cream cheese with lox (fishy, salty); Imported Danish garden vegetable (green pepper and pimento flavor); Le Midi Peche Melba (too sweet, mushy*), Kraft Whipped plain (nothing, airy taste); Kraft with pimento. (tasters objected to eating pink cheese); Kraft whipped bacon-horseradish (too fluffy); Le Midi with orange (too sweet); Imported Danish with peaches (rubbery, too sweet); Le Midi with Pineapple (nasty comments all around).

*The Le Midi brand fruit cream cheeses are better used in place of jam. They are very sweet. The cheese is closer to neufchatel than cream cheese.