Final answer:
The word 'concentrate' is not necessarily included on the label of an EPA-registered disinfectant, whereas efficacy claims, a registration number, and contact time are required elements.
Step-by-step explanation:
The item that will NOT necessarily be on the label of an EPA-registered disinfectant is c) the word 'concentrate'. Per the EPA guidelines, all registered disinfectant labels must include efficacy claims, a registration number, and a contact time to inform users of the product's intended use and proper application. However, whether the product is a concentrate or ready-to-use can vary and is not a required element to be specifically listed on the label.
Efficacy claims are necessary to demonstrate the product's ability to kill specific organisms. The registration number assures the user that the disinfectant has been evaluated and approved by the EPA. Lastly, the contact time indicates the duration the surface must remain wet with the disinfectant to be effective. All of these factors contribute to ensuring that disinfectants are used correctly, especially in clinical settings, where the effectiveness of disinfection protocols is critical for patient and staff safety.