Determinación rápida de coliformes y E. coli en chorizo mediante procedimientos impedimetricos

In the present research have been studied the use of the rapid impedimetric procedures to the detection of the coliformes and E. coli in meat cured sausages, called «chorizo». Two samples of meat cured sausages were selected, one of this was naturally contamined with coliforms and E. coli, and the other one was inoculated. Total coliforms and E. coli were determined following classic methods (violet red bile agar, VRBA, and brilliant green broth, BGB) and impedimetric procedures using coliform medium (CM) and CM with 4-methilumbelliferone-b-D-glucuronide (MUG reagent) for detection of E. coli. The detecton time showed a high regression coeficient (r = 0.93) with the UFC logaritm detected in the VRBA in the studied samples. In general, the impedimetric procedures give the estimation of coliforms in the cured meat sausages, when the number of microorganism is up 50 UFC/g. Moreover, give the detection of E. coli for the hydrolysis of MUG reagent, releasing a flurogenic substrate at 366 nm.