Evaluation of the persistence of SARS-CoV-2 (ATCC® VR-1986HK™) on two different food contact materials: flow pack polyethylene and polystyrene food trays

Abstract

Even though SARS-CoV-2's primary transmission pathway is person-to-person, the role played by surfaces and food contact materials in carrying viral RNA should be further explored. For this purpose, the study aimed to investigate the persistence of SARS-CoV-2 using the strain ATCC® VR-1986HK™ on flow pack polyethylene (FPP) and polystyrene food trays (PFT). Samples of FPP and PFT were contaminated with heat-inactivated SARS-CoV-2 and were incubated at a temperature of 24 ± 1 °C and at controlled relative humidity (RH 65%). The experimental design included analyses at the time 0, 3, 6, 12, 24, 36, 48 and after every 24 h until the viral RNA was no longer detectable. The results showed a significant decrease (P < 0.001) in viral copy numbers on PFT within 3 h (24% reduction) and, at 72 h, the viral RNA had fallen below the limit of detection. Regarding the FPP, it was necessary to wait 24 h for a significant decrease (P = 0.015) in the viral load (14% reduction), while the detection threshold was reached at 96 h. These findings showed that the viral RNA persists longer on flow pack polyethylene samples than on polystyrene food trays, thus highlighting the importance of material characteristics in the persistence of SARS-CoV-2.

Keywords: COVID-19; Fomite; Food packaging; Surface-mediated transmission; Viral RNA detection.

Fig. 1

Distribution of the copy numbers of the SARS-CoV-2 (ATCC® VR-1986HK™) detected at different hours; A: flow pack polyethylene (FPP); B: polystyrene food trays (PFT).

Fig. 2

Residual percentage of the copy numbers of the SARS-CoV-2 (ATCC® VR-1986HK™) revealed at different hours; A: flow pack polyethylene (FPP);B: polystyrene food trays (PFT).