Food Safety Focus (182nd Issue, September 2021) – Incident in Focus

COVID-19 Virus Found on Fish Food Sample – Should I be Concerned?

Reported by Dr. Ken CHONG, Scientific Officer,
Risk Assessment Section, Centre for Food Safety

Background

Last month, COVID-19 virus was tested positive in both food surfaces and food packaging in a batch of chilled pomfret fish from Indonesia. The Centre for Food Safety immediately traced the food’s distribution, with deep cleansing and disinfection in concerned markets and stalls followed up by relevant government departments. Some shoppers expressed concern over the stake of acquiring COVID-19 through chilled or frozen foods. Hereby we shall discuss the relevant risks.

Possibility of Transmission to Consumers via Food or Packaging

According to the World Health Organization, it is highly unlikely that people can contract COVID-19 from food or food packaging. Chilled or frozen foods, like other objects, can be contaminated with COVID-19 virus, especially when handled by infected people. However, rather than multiply in food or on inanimate surfaces, the virus will degrade and become less infectious. Samples being found positive does not mean the presence of viable virus but otherwise previous contamination with the virus, as the test only detects genetic materials of COVID-19 virus, i.e. ribonucleic acid (RNA). Although there were experimental reports on the survival of COVID-19 virus on different surfaces, especially at lower temperatures, these results may not be applicable to real life situations as these experiments are usually conducted under controlled environments in the laboratory. In sum, the risk of virus-positive food samples posed to consumers is very low.

Previous reports on virus-positive chilled or frozen food samples usually indicate the presence of viral RNA but not live virus. This suggests that low temperature may allow the persistence of the virus that has usually been degraded to genetic remnants. Workers handling chilled or frozen foods, especially those at import level, could be at higher risk, as they handle these foods firsthand from places with continued reporting of COVID-19 cases. Therefore, apart from receiving COVID-19 vaccination as soon as possible, workers handling chilled or frozen foods should enhance personal and environment hygiene and take adequate personal protection measures to minimise the risk of COVID-19 infection. They should also disinfect the food package together with the environment of cold stores at import level.

Hygienic Measures for Handling Chilled or Frozen Foods

Although the risk of contracting COVID-19 via food and food packaging is low, people should always uphold good hygiene practices when handling foods, including both chilled and frozen ones. While some people may choose to disinfect food packaging surfaces with alcohol-based wipes or sprays after shopping, it is more important to practice frequent hand washing. Moreover, people should be aware that wearing disposable gloves may lead to a false sense of security, and that wearing gloves should never be a substitute for hand washing. Hands can be contaminated during the removal of used gloves, which therefore should be followed by hand washing. Some practical reminders for consumers on enhancing hygiene are provided in Figure 1.

Figure 1: Some Tips for Consumers to Enhance Hygiene.

As for workers handling chilled or frozen foods in wet markets or other food businesses, they should step up cleansing and disinfection, especially over high-touch points such as handles of refrigerators and food tongs. If possible, high-touch points may better be removed or replaced, for instance, towels placed at fish stalls for consumers can be replaced with alcohol-based handrubs. Furthermore, food handlers also need to reinforce hygiene practices such as frequent hand washing, physical distancing, and wearing protective equipment like masks and face shields.

Key Points to Note

1. Chilled or frozen foods, like other objects, can be contaminated with COVID-19 virus, especially when handled by infected people.
2. Although low temperature may allow the persistence of the virus, it cannot multiply in food or on inanimate surfaces and will degrade and become less infectious.
3. It is highly unlikely that people can contract COVID-19 from food or food packaging.

Advice to the Public

• Maintain personal, food and environmental hygiene at all times.
• Cook food thoroughly to safeguard food safety.
• Always keep hands clean, particularly after handling raw food, after going to toilet and before eating.

Advice to the Trade

• Staff working in the food sector should always maintain hand hygiene, wear appropriate personal protection equipment, and frequently clean and disinfect surfaces, especially high-touch points in the working environments.
• Staff working in the food sector should cease engaging in work and seek medical advice promptly when suffering or suspected to be suffering from infectious diseases or related symptoms.
• Food business operators should encourage their staff to receive COVID-19 vaccination as soon as possible.