Lanthanide-Doped Nanoparticle Compositions for Detecting Microorganisms

A method of biodetection of bacteria in a food product sample, comprising:

• (a) having a particulate lanthanide-doped inorganic material comprising:
• an inorganic host phosphor in a first oxidation state and capable of being reduced to a second oxidation state, the second oxidation state being a relatively lower oxidation state than the first oxidation state;
• a lanthanide ion dopant dispersed in the inorganic host phosphor;
• (b) having a sample container in which at least a portion of the sample container is optically transparent;
• (c) putting the food sample into the sample container;
• (d) promoting growth of bacteria in the food product sample by adding bacterial growth medium into the sample container, or wherein the sample container already contains bacterial growth medium;
• (e) contacting the food product sample with the lanthanide-doped inorganic material by adding the lanthanide-doped inorganic material to the sample container, or wherein the wherein the sample container already contains the lanthanide-doped inorganic material;
• (f) incubating the sample food product at a temperature that is above 20° C.;
• (g) exposing the lanthanide-doped inorganic material to excitation light;
• and
• (h) detecting for emission of luminescent light from the lanthanide-doped inorganic material.