Pathogenic microorganisms associated with Ready-to-Eat fresh-cut vegetables and referred to in the model may include Listeria monocytogenes, Salmonella. , Shigella. , Escherichia coli O157:H7, viruses (Hepatitis A virus, Norovirus, and Rota virus), and parasites (Cyclospora. and Cryptosporidium. ).
An isotope is a form of a chemical element whose atomic nucleus contains a specific number of neutron s, in addition to the number of proton s that uniquely defines the element.The nuclei of most atom s contain neutrons as well as protons.n atom of carbon-14 contains 6 protons and 8 neutrons and is denoted 14 C. Over time, 14 C decays into 12 C. Sometimes the isotope of an element is denoted by writing the nucleon number after the chemical symbol, and not as a superscript.
radioactive isotope. n. An isotope having an unstable nucleus that decomposes spontaneously by emission of a nuclear electron or helium nucleus and radiation, thus achieving a stable nuclear composition. chemical element having the same atomic number as another (i.e. the same number of nuclear protons), but having a different atomic mass (i.e. a different number of nuclear neutrons). radioactive isotope. one having an unstable nucleus and which emits characteristic radiation during its decay to a stable form.