Tolerance of foodborne Acinetobacter spp. to sanitizer agents

The bacteria Acinetobacter spp. are extremely relevant in clinical settings. Recently, they have emerged as potential food-borne opportunistic pathogens. Their ability to form biofilms contributes to antibiotic resistance by generating an environment that facilitates the acquisition and transfer of resistance genes. Studies on the tolerance of Acinetobacter spp. from food sources to sanitizers used in the food industry and homes are necessary to help mitigate food contamination by these microorganisms.

Isolates from ready-to-eat salads (n = 11) and raw goat milk (n = 4) were evaluated for their tolerance to sodium hypochlorite (NaClO), quaternary ammonium compound/biguanide (QAC/BG), and peracetic acid (PAA). The Food and Drug Administration (FDA) recommends that the concentration of these sanitizers in food-processing equipment and utensils and other food-contact articles should not exceed 200 parts per million (ppm).

The minimum inhibitory (MIC) and bactericidal (MBC) concentrations of NaClO were above 312.5 ppm for all isolates tested and ≥ 2,500 ppm for four isolates from salads. Only three isolates from salads and four isolates from goat milk were inhibited by an MIC lower than 200 ppm of PAA. QAC/BG presented the lowest MIC and MCB values (9.37/6.25  ppm for all isolates tested), suggesting that it is the most effective agent against the isolates used in this study.

Our results demonstrate that Acinetobacter spp. isolates from food can be tolerant to the recommended concentrations of NaClO and PAA, which highlights the health risks to consumers.