Can the coronavirus disease be transmitted from food? A review of evidence, risks, policies and knowledge gaps

Abstract

The coronavirus disease 2019 (COVID-19) has brought speculations on possible transmission routes of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causal agent of the pandemic. Air pollution has been linked to increased risks of COVID-19 infection and mortality rates in regions with poor air quality, yet no retrospective study has been reported on foodborne transmission of COVID-19. While studies have shown that low temperature could dramatically prolong the persistence on SARS-CoV-2 and other coronaviruses, frozen and refrigerated foods have been widely overlooked as potential vectors in policy frameworks and risk mitigation strategies. Food transmission evidence has been disclosed in China early July 2020 by the detection of SARS-CoV-2 on frozen foods, including their packaging materials and storage environments, with two re-emergent outbreaks linked to contaminated food sources. The contamination risk is augmented by a complex farm-to-table process, which favors exposure to food workers and ambient environments. Moreover, the food cold-chain also promotes contamination because laboratory studies showed that SARS-CoV-2 remained highly stable under refrigerated, at 4 °C, and freezing conditions, from - 10 to - 80 °C, on fish, meat, poultry, and swine skin, during 14-21 days. While data are lacking on long-term survival and infectivity under these conditions, ample evidence has been shown on other coronaviruses, including SARS-CoV-1. We therefore hypothesize that contaminated cold-storage foods may present a systematic risk for SARS-CoV-2 transmission between countries and regions. Here, we review the evidence, risk factors, current policy and knowledge gaps, on food contamination and foodborne transmission of SARS-CoV-2.

Keywords: Cold chain; Coronavirus; Food; Frozen; Logistics; Refrigerated.

Fig. 1

Routes of virus transmission in food retailing environment during the coronavirus disease 2019 (COVID-19) pandemic. Frozen and refrigerated foods as well as commonly touched surfaces including shared tongs, handles on bakery and refrigerated cabinets, shopping baskets, payment terminals are highlighted for their elevated risk of contamination by the virus. The optional wearing of face coverings by shoppers and staff reflects current regulatory guidelines

Fig. 2

Detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on imported frozen raw foods across China between early July 2020 and mid-August 2020. Information was compiled from announcements by local authorities. In most cases, the novel coronavirus was found on food packaging materials, although it was also detected in food storage environment (Dalian) and food surface (Shenzhen). The percentage of positive samples found in each investigation was not specified in any of these reported incidents. According to the current standard, customs and public health authorities in China are required to test no more than 10 samples in each importation of animal products with over 10,000 units or 10,000 tons in total weight

Fig. 3

Possible contamination of refrigerated and frozen foods during the coronavirus disease 2019 (COVID-19) by exposing to various food workers and environments in the entire “farm-to-table” process and the survival of the novel coronavirus throughout the “cold chain” of storage, transport, and retailing of these foods. Contamination may occur via respiratory droplets from infected individuals or contact routes via virus-laden hands, surfaces, and tools