ENCICLOPEDIA BRITANNICA
raisins: a grape of any of several varieties that has been dried in the sun or by artificial heat;raisin grapes are the Thompson Seedless, a pale-yellow seedless grape, also known as Sultanina (California); Muscat, or Alexandria, a large-seeded variety also known as Gordo Blanco (Australia); White Hanepoot (South Africa); and the Black Corinth, a small, black, seedless type, also called Zante currant, Staphis (Greece), and panariti. Other varieties of raisin of local importance include the Round Kishmish, Rosaki, Dattier, Monukka, and Cape Currant.
sultana: a pale yellow seedless grape grown for raisins and wine;the raisin of a sultana
currant: the name currant is also applied to a seedless raisin grown chiefly in the Levant; the acid edible fruit of several shrubs (genus Ribes) of the saxifrage family;

Sono tutti tipi di uva passa. L'uva sultanina si presenta in modo diverso perchè è un tipo di uva bianca con acino grande. Mentre il currant (che tradurrei come uva di Corinto) è piccola e scura, senza semi.