8/24/2016 Surface Testing Swab Test Method ·Most common in food- Food contact surfaces should be tested processing facilities for their hygienic state Moistened cotton or calcium Inherent problem-consistent removal alginate swab (dissolves) of microbes from the surface Sterile templates define the area size Swab placed in a diluent Standard plate counts performed Ideal for rough,uneven surfaces Contact Agar Plates Other Methods a raised agar Simply incubate the plate These methods are all common Sterile sticky tape conventional methods ·Pressed against a Selective media may be used to premeasured surface Pressed to an agar plate enhance detection of specific microbes Sponge system May be combined with rapid methods to Moistened sponge wiped decrease the time required for across the test area identification of microbes found in food. ·Placed into diluent Standard plate count performed 8 8/24/2016 8 Surface Testing • Food contact surfaces should be tested for their hygienic state • Inherent problem – consistent removal of microbes from the surface 29 Swab Test Method • Most common in food￾processing facilities • Moistened cotton or calcium alginate swab (dissolves) • Sterile templates define the area size • Swab placed in a diluent • Standard plate counts performed • Ideal for rough, uneven surfaces 30 Other Methods Contact Agar Plates • Petri plate has a raised agar surface • Simply incubate the plate Sterile sticky tape • Pressed against a premeasured surface • Pressed to an agar plate Sponge system • Moistened sponge wiped across the test area • Placed into diluent • Standard plate count performed 31 • These methods are all common conventional methods • Selective media may be used to enhance detection of specific microbes • May be combined with rapid methods to decrease the time required for identification of microbes found in food. 32