Evaluation of a Test Strip Used to Monitor Food Processing Sanitation

Abstract

A test strip, which contained a small absorbent pad on the end of a plastic strip for detection of microbial contamination of liquids and surfaces, was compared to standard rinse solution and surface contact methods. Bottles and food contact surfaces were unclean, cleaned or cleaned and sanitized before being evaluated with test methods. Results from test strips correlated well with those of the standard rinse solution method for bottles that were clean and/or sterilized, but not for those that were heavily contaminated. When test strips were used on cleaned contact surfaces, counts were one log cycle greater than those of contact plate or swab methods; however, the three surface methods correlated well for surfaces that were cleaned and sanitized. To insure that the contact methods were recovering microorganisms, surfaces were spread with known levels of Escherichia coli and Staphylococcus aureus. Results correlated well for low levels of contamination, but not for levels greater than 1 × 104 organisms/25 cm2 Overall, test strips could be used for quick indication of sanitation of cleaned and sanitized food contact surfaces and containers if special precautions and limitations were understood.