Meat factories

In Germany there was an outbreak in a meat factory during the summer in 2020:

• Coronavirus: What went wrong at Germany's Gütersloh meat factory?
  
• Tönnies: infection center meat factory 
• (picture from here)

In January 2021, a covid cluster was found among workers of a chicken processing plant: China finds COVID cluster at major chicken processing plant.

These news suggest that we must search for the reason of this massive virus spread in accommodational circumstances of the workers, or failure of wearing masks or keeping sufficient distance in the canteen. 

In my opinion there must be more specific reasons here, as these above must have been existent in many more places / areas after the re-opening of the industries. There are specific issues with humidity / condensation in the meat industry as higienical processing and storage of fresh meat requires very specific temperature conditions.

Coolers should be kept relatively humid and humidity should be carefully controlled in general. Different humidity / temperature requirements in different parts of the plant:

Moisture (humidity) control is of utmost importance in a meat plant or a sausage kitchen. Any moisture that will show on meats as water droplets will create perfect conditions for the development of bacteria. The products will also feel "slimey". The recommended humidity levels for meat processing rooms are:

meat cutting room 45 - 60% relative humidity at 10° - 12° C (50 - 54° F)
coolers 85 - 95% relative humidity at 0° - 4° C (32 - 36° F) 

    Humidity Control (published in Meats and Sausages)

The cleaning process also plays an important role here:

Sanitation often is the primary, even sole, source of the problem. After two eight-hour processing shifts in a cold environment, the introduction of hot water during the clean-up shift is bound to upset the moisture balance.

    Plant Moisture Control (published in Food Processing)