Quaternary ammonium compounds (QACs) are sometimes referred to as quats. These compounds are among the most commonly used disinfectants in the food industry, and there are numerous commercially available products and formulations. They are cationic surfactants (positively charged surface-active agents) that impact cell walls and membranes after relatively long contact times. Their permanent positive charge makes them bind readily to the negatively charged surface of most microbes. Quaternary ammonium compounds (commonly known as quats or QACs) are cationic surfactants (surface active agents) that combine bactericidal and virucidal (generally only enveloped viruses) activity with good detergency and, therefore, cleaning ability. Although other surfactant types, such as anionic, nonionic and, amphoteric surfactants (referring to their overall charge) have some antimicrobial activity depending on the specific biocide, the cationic surfactants (and some of the amphoterics) have the greatest antimicrobial activity. Being positively charged, they are rapidly attracted to the cell wall surface, with initial surface structure disruption, penetration to the cell membrane, and direct insertion to and interaction with the phospholipids, leading to structure/function disruption (including leakage of cytoplasmic components); these effects culminate in cell death and loss of viability of enveloped viruses. QACs are not aggressive on surfaces, and have low toxicity.