compatibly into the grooves 2 a 2 b in the circular base 1 this disposable crossed piercing picker 5 has a needle point 6 at the centre with a diameter of 8 mm and a height of 1 4 mm which serves to pierce and pick up the two graduated paper strips from the circular base 1 and place them on the bacterial culture medium on the petri dish in order to facilitate the picking up of the two graduated paper strips the fitting of a further four needles points 6 a 6 b 6 c 6 d with a diameter of 6 mm and a height of 0 4 mm is provided for the said points being positioned at an equal distance of 7 5 mm from the centre of the needle point 6 for the purpose of preventing the possible rotation of the strips around the needle during transfer concentric to the circular hollow 3 of the circular base 1 is the circular hollow 4 which has a diameter of 4 mm and a depth of 5 4 mm the purpose of which is to facilitate the sinking of the needle of the disposable crossed piercing picker 5 into the two graduated paper strips in such a way as to pick them.