14 BULLETIN 468, U. S. DEPARTMENT OF AGRICULTURE. 
and is said to be what gives them their characteristic flavor. Such 
very small quantities are not harmful, and for that matter the 
amount which develops in sprouting or green tubers is not usually 
dangerous; but since the flavor is very often bad, it is a good rule 
to avoid green tubers or to cut out any green sections before cooking 
them. 
The illness (often serious and sometimes fatal) attributed to green 
tubers, which occasionally results after eating cooked potato salad, 
for instance, is due, not to solanin or any other such substance, but 
to the rapid growth in the digestive tract of harmful bacteria 
(usually of the group called fecal bacteria) accidentally present on 
the potato or some food served with it and conveyed to the food 
most often by the unclean hands of some one who has handled, cooked, 
or served it. 
i SELECTION OF POTATOES FOR TABLE USE. 
Appearance, taste, and consistency are the points by which we 
judge a cooked potato. Unfortunately, it is not always easy to tell 
from the appearance of raw potatoes which will prove the best, but 
there are certain marks which aid in making a choice. 
Young or new potatoes are preferable to old or stored ones. Such 
tubers usually have a smoother skin, though they are not as mealy 
and do not keep as well as the older ones. Very large potatoes are 
not especially desirable, partly because it is hard to cook them 
evenly and partly because the} 7 are often very variable in texture. 
Smooth, regularly shaped tubers with comparatively few eyes are 
more economical than irregular ones which can not be pared without 
considerable waste. 
Different varieties may have distinct flavors, but the soil and 
climate in which they are grown and the fertilizers used cause such 
great differences in flavor that variety alone is no sure guide. The 
freshly gathered mature tubers usually contain a large proportion of 
mineral matters and acids, and therefore have the better flavor. 
Tubers old enough to sprout begin to develop an acrid taste, probably 
due in part to an increased solanin content. 
Very water} 7 potatoes are always undesirable, because they become 
soggy in cooking. Young tubers are more juicy than mature ones, 
but their juice often holds so much more protein in solution that they 
cook to the well-known waxy consistency. A good potato to be 
mealy when cooked should feel firm when pressed in the hand. If 
cut, it should separate crispry under the knife and be of even density 
throughout. If the core is large and soft, it will make a soggy mass 
full of holes in the center. 
