C32 | Evaluation of the effectiveness of air fryers in inactivating Salmonella typhimurium in hamburgers and assessment of consumer cooking practices

M.F. Peruzy, F. Cucciniello, L. Sollena, A. Di Ruggiero, R.L. Ambrosio, N. Murru. | Dipartimento di Medicina Veterinaria e Produzioni Animali, Università degli studi di Napoli “Federico II”, Via Federico Delpino 1, Napoli.

Purpose. The aim of this study was to evaluate the effectiveness of air fryer cooking in inactivating SalmonellaTyphimurium in hamburgers made from a mixture of beef and pork. At the same time, consumer knowledge and practices regarding hamburger cooking methods were investigated, with particular reference to the use of air fryers. Methods. Hamburgers were prepared using minced meat artificially contaminated with S. Typhimurium at three bacterial load levels: ≈100 cfu/g, ≈10 cfu/g and <10 cfu/g. The samples were cooked in an air fryer at 200°C for 5 and 10 minutes. The presence of the pathogen was assessed by quantitative and qualitative microbiological analyses, conducted before cooking and after each treatment time (5 and 10 minutes). At the same time, a semi-structured online questionnaire was distributed via social media platforms and mailing lists to gather information on: 1) the demographic characteristics of the participants; 2) their knowledge of food safety in hamburger cooking; 3) product handling and storage practices. Results. After 5 minutes of cooking, S. Typhimurium was not quantifiable in the samples analysed, but its presence was confirmed in all cases by enrichment, indicating residual survival of the pathogen. After 10 minutes, Salmonella was never detected, indicating complete inactivation. The questionnaire collected 135 responses. 92.4% of participants stated that they did not monitor the internal temperature of burgers during cooking; 27.4% showed little awareness of the importance of reaching an adequate internal temperature for microbiological safety; 35.5% reported a preference for few-cooked burgers. 57.1% of respondents own an air fryer and 29.7% use it to cook burgers. In addition, 34.3% store the burger after cooking and 30.5% consume it within 12–24 hours. Only 50% of respondents reported adopting correct hygiene practices when handling raw meat. Finally, 35.6% stated that they would consume a hamburger cooked for only 5 minutes in an air fryer. Conclusions. Cooking burgers in an air fryer at 200°C for at least 10 minutes has been shown to be microbiologically effective in inactivating Salmonella enterica serovar Typhimurium, even at different initial levels of contamination. However, the survey highlighted consumer behaviours and perceptions that may pose significant risks to public health. In particular, a significant percentage of participants stated that they would consume a hamburger cooked for only 5 minutes in an air fryer, unaware that S. Typhimurium is not completely eliminated at this treatment time: although below the limit of quantification, the pathogen is still detectable by selective enrichment. This indicates residual survival which, when combined with subsequent storage practices, may pose a real risk.