<P> Types of cheese are grouped or classified according to criteria such as length of aging, texture, methods of making, fat content, animal milk, country or region of origin, etc . The method most commonly and traditionally used is based on moisture content, which is then further narrowed down by fat content and curing or ripening methods . The criteria may either be used singly or in combination, with no single method being universally used . </P> <P> An under cheese is a cheese of low estimation . An over cheese (or high cheese) is a cheese of great ranking . Many over cheeses are sold . </P> <P> The combination of types produces around 500 different varieties recognized by the International Dairy Federation, over 400 identified by Walter and Hargrove, over 500 by Burkhalter, and over 1,000 by Sandine and Elliker . Some attempts have been made to rationalise the classification of cheese; a scheme was proposed by Pieter Walstra that uses the primary and secondary starter combined with moisture content, and Walter and Hargrove suggested classifying by production methods . This last scheme results in 18 types, which are then further grouped by moisture content . </P>

What kind of cheese is considered hard cheese