Biofilm Formation and Phenotypic Disinfectant Tolerance of Foodborne Bacteria on Food-Contact Surfaces in Processing Environments

Marwa Attayeb; Aziza Abdelgawad; Fauzia Abuhtna; Mansor Wafi; Awatif Almaqrahi; Budour Elmihub; Mohanned Alwashaish

doi:10.54361/ajmas.269714

Authors

Marwa Attayeb Department of Microbiology, Libyan Biotechnology Research Center, Tripoli, Libya https://orcid.org/0009-0006-2821-968X
Aziza Abdelgawad Department of Microbiology, Libyan Biotechnology Research Center, Tripoli, Libya https://orcid.org/0000-0002-2885-277X
Fauzia Abuhtna Department of Microbiology, Libyan Biotechnology Research Center, Tripoli, Libya https://orcid.org/0000-0003-3911-4913
Mansor Wafi Department of Microbiology, Libyan Biotechnology Research Center, Tripoli, Libya https://orcid.org/0009-0001-4650-0516
Awatif Almaqrahi Department of Environmental, Food and Biological Applications, Libyan Biotechnology Research Center, Tripoli, Libya https://orcid.org/0000-0001-5654-2704
Budour Elmihub Department of Microbiology, Libyan Biotechnology Research Center, Tripoli, Libya https://orcid.org/0009-0007-4612-7874
Mohanned Alwashaish Biomedical Science Department, Faculty of Pharmacy, Misurata University, Misurata, Libya https://orcid.org/0009-0002-2014-3693

DOI:

https://doi.org/10.54361/ajmas.269714

Keywords:

Biofilm formation, Food-contact surfaces, Disinfectant tolerance, Quaternary ammonium compounds, Food-processing environments

Abstract

Food-contact surfaces can act as reservoirs for persistent foodborne bacteria, particularly when biofilms reduce the effectiveness of routine sanitation. This cross-sectional study investigated bacterial contamination, biofilm formation, and phenotypic disinfectant tolerance among isolates recovered from food-processing environments in Tripoli, Libya. A total of 240 food-contact surface samples were collected from meat, dairy, vegetable, and ready-to-eat food facilities. Overall, 151 samples (62.9%) were culture-positive, with the highest positivity observed in meat-processing facilities (74.3%) and raw-material handling areas (75.0%). A total of 166 bacterial isolates were recovered; Listeria monocytogenes was the most frequent species (19.3%), followed by Staphylococcus aureus (18.1%) and Salmonella enterica (16.9%). Strong biofilm formation was detected in 81 isolates (48.8%), particularly among Pseudomonas aeruginosa (68.0%) and L. monocytogenes (65.6%). Biofilm-associated isolates showed the highest tolerance to QAC-based disinfectants (41.0%), followed by sodium hypochlorite (20.5%), hydrogen peroxide (17.5%), and peracetic acid (10.8%). Strong biofilm formation independently predicted tolerance to at least one disinfectant (aOR = 4.87), whereas cleaning surfaces at least three times daily reduced this likelihood (aOR = 0.42). Enhanced residue removal, biofilm-focused sanitation, and targeted monitoring of high-risk surfaces are essential to reduce persistent contamination and improve food safety.