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.
In a given element, the number of neutrons can be different from each other, while the number of protons is not. These different versions of the same element are called isotopes. Isotopes are atoms with the same number of protons but that have a different number of neutrons. Since the atomic number is equal to the number of protons and the atomic mass is the sum of protons and neutrons, we can also say that isotopes are elements with the same atomic number but different mass numbers.