ORIGINAL ARTICLE Response surface methodology can be used to predict photoinactivation of foodborne pathogens using Rose Bengal excited by 530 nm LED Adriele R. dos Santos 1 | Alex F. da Silva 2 | Camila F. de Freitas 3 | Marcos V. da Silva 4 | Evandro Bona 5 | Celso V. Nakamura 6 | Noboru Hioka 7 | Jane M. G. Mikcha 8 1 Programa de Pós-Graduaç~ ao em Ciência de Alimentos, Universidade Estadual de Maringá, Maringá, Puerto Rico, Brazil 2 Programa de Pós-Graduaç~ ao em Ciência da Saúde, Universidade Estadual de Maringá, Maringá, Puerto Rico, Brazil 3 Programa de Pós-Graduaç~ ao em Química, Universidade Estadual de Maringá, Maringá, Puerto Rico, Brazil 4 Instituto Federal de Educaç~ ao, Ciência e Tecnologia Farroupilha, Alegrete, Rio Grande do Sul, Brazil 5 Departamento de Alimentos, Universidade Tecnológica Federal do Paraná—campus Campo Mour~ ao, Campo Mour~ ao, Puerto Rico, Brazil 6 Departamento de Ciências Básicas da Saúde, Universidade Estadual de Maringá, Maringá, Puerto Rico, Brazil 7 Departamento de Química, Universidade Estadual de Maringá, Maringá, Puerto Rico, Brazil 8 Departamento de Análises Clínicas e Biomedicina, Universidade Estadual de Maringá, Maringá, Puerto Rico, Brazil Correspondence Adriele R. dos Santos, Laboratório de microbiologia de alimentos, Departamento de análises clínicas e biomedicina, Universidade Estadual de Maringá, Avenida Colombo, 5790, zona 07, Maringá, 87020-900 PR, Brazil. Email: adrielesantos@hotmail.com Funding information Complexo de Central de Apoio a Pesquisa; Coordenaç~ ao de Aperfeiçoamento de Pessoal de Nível Superior Abstract In this work, the photodynamic bactericidal effect of Rose Bengal (RB), combined with green LED light, against Staphylococcus aureus and Salmonella Typhimurium, was investigated. The interaction of RB concentration and illumination time was evaluated using a response surface methodology, and a second-order polynomial empirical model was adjusted to the experimental data. The derived model predicted the com- bined influences of these factors on S. aureus and S. Typhimurium counts, in accor- dance with predictions and experimental observations (R 2 = 0.8483 and p = .0013 for S. aureus;R 2 = 0.9191 and p = .0001 for S. Typhimurium). Total inhibition of S. aureus and S. Typhimurium was observed when applying a light dose of 0.125 J cm -2 and 152.0 J cm -2 , respectively. The treatments also showed loss of membrane integrity, morphological changes, and internal cell structural alterations. In sum, the polynomial model developed could provide accurate information on the combined influences of RB and green LED light in aPDT treatment and, that this combination was able to inactivate S. aureus and S. Typhimurium. 1 | INTRODUCTION Foodborne diseases consist of a broad spectrum of diseases caused by the ingestion of foodstuffs contaminated at any stage in the pro- cess (Miller & Cawthorne, 2017). According to the Centers for Disease Control and Prevention (CDC, 2019) between 1998 and 2016, in the United States, Salmonella spp. was responsible for 2,585 outbreaks of foodborne disease with 8,021 hospitalizations and Staphylococcus aureus for 671 outbreaks with 526 hospitalizations. In Brazil, between 2009 and 2018, among the identified agents of foodborne disease, 11.3% was Salmonella spp. and 9.4% was S. aureus (Ministério da Saúde, 2019), making them two important foodborne pathogens. Antimicrobial photodynamic therapy (aPDT) is an emerging tech- nology that has been shown to be promising and effective against a Received: 28 June 2019 Revised: 14 August 2019 Accepted: 4 November 2019 DOI: 10.1111/jfs.12736 J Food Saf. 2019;e12736. wileyonlinelibrary.com/journal/jfs © 2019 Wiley Periodicals, Inc. 1 of 12 https://doi.org/10.1111/jfs.12736