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The bactericidal activity on Listeria spp. of nine disinfectants used in the food industry was studied by previously published methods. The disinfectants were diluted to the test concentration in sterile standard hard water. Various types of chemical agents were evaluated, including phenolic compounds, alcohols, quaternary ammonium compounds, surface-active agents, aldehydes and disochlorine tablets. The following strains isolated from cheese were studied: Listeria innocua, L. welshimeri, L. monocytogenes 1/2a, 1/2b, 1/2c and 4b. The results show that the listerias are not particularly resistant to disinfectants but the efficacy of some agents is affected by organic matter.

The microbial contamination and antimicrobial effectiveness of seven topical disinfectants prepared at the hospital pharmacy were studied. These products were controlled throughout storage and use. The manufacturing routine investigated was able to deliver larger batch sizes and quality products that allowed increased storage time. The formulations chosen by the pharmacists were effective against bacteria for their intended uses. For chloramine only, loss of effectiveness required reduced storage time. No significant modification in the microbial quality of these products was observed during use in our hospital.