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Research Article | 20 Jun 2026

Chitosan as a sustainable decontamination strategy against Salmonella and Listeria monocytogenes on pig carcass surfaces: Comparative efficacy with organic acids

Maria Ciríaco1,2, Márcio Moura-Alves1,2, Kamila Soares1,2, Isabel Pinto3, Cristina Saraiva1,2, and Alexandra Esteves1,2 Show more
VETERINARY WORLD | Article No. 21 | pg no. 2554-2567 | Vol. 19, Issue 6 | DOI: 10.14202/vetworld.2026.2554-2567
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ABSTRACT

                      
Background and Aim: Controlling bacterial contamination on pig carcasses is critical for meat safety and public health within the One Health framework. Salmonella and Listeria monocytogenes are major foodborne pathogens associated with pork products. This study evaluated the decontamination efficacy of chitosan (0.2% and 0.5%) compared to lactic acid (2% and 5%) and citric acid (2% and 5%) against Salmonella Typhimurium and L. monocytogenes inoculated on pig skin surfaces, while also assessing effects on spoilage microbiota (mesophilic bacteria, psychrotrophic bacteria, and Enterobacteriaceae). The goal was to identify sustainable, natural alternatives to conventional organic acid treatments for early-stage carcass interventions in slaughterhouses. 
Materials and Methods: Pig skin samples (25 cm²) were collected from commercial carcasses, inoculated with approximately 5–6 log colony-forming units per square centimeter of the target pathogens or left non-inoculated, and treated by spraying with the respective solutions. Samples were stored at 7 °C for 48 h. Microbial enumeration followed International Organization for Standardization methods for mesophiles (Plate Count Agar, 30 °C/72 h), psychrotrophs (Plate Count Agar, 7 °C/10 days), Enterobacteriaceae (Violet Red Bile Glucose agar), Salmonella (Xylose Lysine Deoxycholate agar), and L. monocytogenes (Oxford agar). Data were analyzed using one-way analysis of variance and Tukey honestly significant difference test (p < 0.05). 
Results: Organic acids provided modest initial reductions (<1 log) in spoilage organisms and mainly bacteriostatic effects against pathogens. Chitosan at 0.5% achieved the strongest reductions, lowering initial mesophilic and psychrotrophic counts by >1 log and maintaining the lowest L. monocytogenes levels (only +0.44 log increase over 48 h vs. >2 log in controls). For Salmonella, 0.5% chitosan produced a progressive 1.46-log reduction over 48 h (final counts 2.68 log lower than the control), demonstrating bactericidal activity, unlike the bacteriostatic profile of organic acids. 
Conclusion: Chitosan, particularly at 0.5%, exhibited superior, more sustained antimicrobial efficacy against both pathogens and spoilage microbiota on pig skin compared with lactic and citric acids. These findings highlight chitosan as a promising natural, sustainable decontamination agent for pig carcasses, with the potential to enhance compliance with European Union microbiological criteria and support greener meat-processing strategies. Further commercial-scale validation and combination approaches are recommended. 
                      
Keywords: carcass decontamination, chitosan antimicrobial, foodborne pathogens, Listeria monocytogenes, meat safety, organic acids, pig carcasses, Salmonella control.