## 6 Use of Chemical Agents  
Antimicrobials are substances that inhibit or kill microorganisms, including both bacteriostatic (prevent growth) and bactericidal (kill microorganisms) agents. In the United States, regulations for antimicrobials vary depending on how they are used. The differences between disinfectants and antibiotics are significant. Antibiotics are chosen based on the susceptibility of microorganisms, and their action targets specific components of the cells, which can lead to resistance by modifying these components. Disinfectants, on the other hand, are selected based on their intended use, interaction with materials, and cost. Unlike antibiotics, some disinfectants contain one or more active ingredients. Advice on their selection is usually provided by disinfectant suppliers. Food safety practitioners have the responsibility of translating scientific research into effective industrial practices. A major challenge is a terminological confusion, an example of which is the different interpretations of the term \"disinfectant resistance\". In the scientific literature, it may describe the ability of a bacterium to survive sublethal doses of disinfectant, while the industry may understand that the product is ineffective even at maximum concentrations. Practitioners need to understand and clearly communicate these nuances, especially in facilities producing ready-to-eat (RTE) foods, where cleaning and sanitation are essential for the control of _L. monocytogenes_ and other pathogens [170]. To the best of our knowledge, true resistance to disinfectants has not been observed in _L. monocytogenes_ at recommended concentrations and conditions of use [171]. Hygienic design of equipment and facilities, as stipulated in international regulations, is crucial for the effectiveness of cleaning. Smooth, non-absorbent, and easy-to-clean surfaces are essential to prevent contamination with microorganisms. Hard-to-reach equipment, worn materials, and porous surfaces are hiding places for pathogens, including _L. monocytogenes_. Cleaning of components that do not come into direct contact with food is also important, as they can serve as sources of contamination [172]. Disinfectant rotation is a practice used to prevent the development of antimicrobial resistance in food processing facilities. It involves alternating disinfectants with different active ingredients to reduce the risk of microbiome adaptation. Although this practice is recommended by the FDA (2017) for the control of _L. monocytogenes_ in ready-to-eat (RTE) foods, scientific support for disinfectant rotation remains limited. The available studies are mostly guidelines documenting common practices, but there is no clear evidence that rotation is essential for food safety [173]. Although disinfectant rotation is not harmful, its implementation as an essential practice without a solid scientific basis can lead to unnecessary complications. More research is needed to evaluate the effectiveness of this method and the long-term impact of microbial tolerance to disinfectants [174]. In the food industry, cleaning and sanitizing are essential for the removal of microorganisms and soil from surfaces, equipment, and food contact areas. Various chemicals, such as chlorine, chlorine dioxide, hydrogen peroxide, quaternary ammonium compounds, ozone, and others, are used in these processes [175]. Aqueous chlorine is effective in controlling microbial growth, but its activity decreases under alkaline conditions, forming toxic substances such as chloramines and trihalomethanes (THMs). In this context, chlorine dioxide (ClO\({}_{2}\)) is a superior alternative, having double the oxidative power and being more effective under alkaline conditions and in the presence of organic compounds. Research shows that ClO\({}_{2}\) in the gaseous state has greater penetrability, being more effective in eliminating microorganisms hidden in surface irregularities and biofilms [176]. [PERSON] et al.