P24 | Microbiological criteria as a tool for evaluating good hygiene practices in sushi preparation

A. Sardella¹, L. Barco¹, L. Grassi², M. Bergantin¹, G. Bozzolan¹, G. Fabbri¹, E. Fornasiero¹, S. Friso¹, E. Marafin¹, M. Milan¹, E. Selmin¹, G. Zanardi¹, P. Zavagnin¹, L. Chiementin³, R. Francia³, G. Toniolo³, L. Bossa³, K. Capello⁴, I. Pascuci⁴, V. Cibin⁴. | ¹SCS1 – Microbiologia generale e sperimentale, Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro; ²4SCT4 – Sezione territoriale di Udine, Istituto Zooprofilattico Sperimentale delle Venezie, Udine; ³SIAN – Servizio Igiene degli Alimenti e Nutrizione, Azienda ULSS 8 Berica, Vicenza; ⁴SCS4 – Epidemiologia, servizi e ricerca in sanità pubblica veterinaria, Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro (PD), Italy

The term "sushi" is generally used to refer to typical Japanese rice-based dishes. Due to the use of cooked and cooled ingredients such as rice, and raw ingredients of animal and plant origin, sushi can be more susceptible than other preparations to contamination with microbiological hazards potentially responsible for foodborne illness (MTA); Reducing consumer risk cannot be achieved without the correct application of the instructions provided in self-monitoring manuals during the preparation and storage phases. This paper, which is part of a project called "Good Hygiene Practices in Sushi Preparation Activities" by AULSS 8 of Veneto, describes the results of microbiological and physicochemical analyzes conducted to evaluate the hygiene and health conditions of a selection of sushi restaurants in the Vicenza area. Sixteen restaurants representative of the local area were selected based on reports of MTA incidents via social media. For each activity, before the serving shifts, the following were collected: a sample of cooked rice and two samples of finished products with rice and raw fish (nigiri, hosomaki). The microbiological parameters and their respective methods and limits were selected using the following sources: Regulation (EC) 2073/2005, the State-Regions Conference No. 212 of 2016 and subsequent amendments, and the "Guidelines for assessing the microbiological safety of ready-to-eat foods placed on the market" from the UK Health Security Agency. Coagulase-positive staphylococci (CPS), presumptive Bacillus cereus (PBC), total mesophilic count (TMC), pH measurement, and water activity (aw) were performed on all matrices. Additionally, the presence of Salmonella spp. and Listeria monocytogenes was tested in the finished products. A total of 48 samples were analyzed, none of which tested positive for Salmonella spp. and Listeria monocytogenes. For the count of SCP, 3 samples of the finished product had values of 300 cfu/g, 1300 cfu/g, and 1500 cfu/g respectively, while one sample of rice had a value of 1200 cfu/g; For the BCP, all samples tested below 1000 CFU/g; The CMT was satisfactory (<106 cfu/g) in 44 samples and borderline (between 106 and 107 cfu/g) in 4 finished products. All samples had aw values >0.96; The pH values ranged from 4.0 to 4.8 for cooked rice and 4.8 to 5.9 for the finished products. No pathogenic microorganisms were detected in any of the samples analyzed, and no particular critical issues emerged regarding the process hygiene parameters. However, in 3 restaurants, microbiological contamination levels were detected that, although within limits, are indicative of improvable hygiene and sanitation conditions; Furthermore, it is highlighted that despite 13 out of 16 restaurants using the rice cooking method with acidification, this was not always sufficient to ensure a pH <4.6. Although the study allows for a generally favorable judgment to be expressed for the selected sushi restaurants, the project aims to introduce guidelines within self-control manuals and training sessions to raise awareness of the tools/rules designed to ensure excellent quality in preparations.