Bacterial Content of Gravy Bases and Gravies Obtained in Restaurants1

Abstract

Forty-one samples of dry commercial gravy bases (involving ten brands), and 44 prepared gravies from these bases were collected from 28 restaurants, drive-ins and coffee houses in the Edmonton area. All samples were examined for SPC, and for presence of coliforms, thermophiles, coagulase-positive staphylococci, salmonellae and Cl. perfringens. No salmonellae or Cl. perfringens were detected in any of the samples examined. Some gravy bases and gravies showed presence of coliforms, thermophiles, coagulase-positive staphylococci and other bacteria. All coliforms and staphylococci were eliminated after three-minute boiling, but SPC and thermophile counts decreased very slowly during further boiling. A number of ingredients used in the preparation of gravy bases also were investigated. Some coagulase-positive staphylococci were detected in onion powder and ground savory, and large numbers of coliforms were detected in ground sage, marjoram, alaman paprika and black pepper. However these organisms were eliminated after three-minute boiling. The investigations revealed that there was little danger for foodborne illnesses from gravies prepared from commercial gravy bases, providing one follows the preparation instructions, boil the gravies for at least five minutes, and hold the product at 160°F prior to serving.