Can the tunnel-type washing unit meet the disinfection requirements of WS/T508?

The internal structure of the tunnel-type washing unit is fully interconnected and communicates with the workshop air, causing the bacteria present in the laundry room’s air to adhere to the surfaces of its interconnected internal structures. Moreover, the interior of the tunnel-type washing unit maintains a humid and warm environment, which is highly conducive to bacterial proliferation. Even more concerning is that the spiral discharge channel inside the unit is not submerged in water. Although this channel is located in the heating zone, its actual position does not receive effective heating from the washing solution; instead, its temperature remains significantly lower than that of the washing solution itself, far from reaching the temperature required for disinfection. If the situation is already so precarious in the heating zone, it is even less likely to achieve proper disinfection in non-heating zones. Furthermore, after prolonged use, the surfaces of these channels become heavily encrusted with scale. During the washing process, each batch of textiles must slide down along these scaled surfaces, carried by the water accumulated in the current chamber, before moving on to the next chamber. In summary, in medical laundries that handle medical textiles, the structural design of this type of equipment fails to meet the technical requirements specified in WS/T 508-2016 regarding microbial indicators—for example, it must not detect Escherichia coli or Staphylococcus aureus, and the total colony count must also exceed the permissible limits.
The judgment that it fails to meet microbiological standards is theoretically sound—just as the saying goes, “A rod one foot long, halved each day, will never be exhausted over ten thousand generations”; in theory, pathogenic bacteria must inevitably be present.
Based on data on the types of pathogens typically detected in medical laundry environments, please assess the pathogen levels found on the continuous internal surfaces of tunnel-type washing machines. Then, analyze why this product fails to meet the microbial standards specified in the relevant regulations. Use clear and straightforward language for your explanation.

In the environment of medical laundry facilities, common pathogens include Escherichia coli, Staphylococcus aureus, Salmonella, and others. These pathogens typically spread through air, water, or textiles. The internally贯通 structure of tunnel-type washing machines—especially the spiral discharge channel—provides an ideal breeding environment for these pathogens.

Humid and hot environment: The high humidity and temperature conditions inside the tunnel-type washing unit are highly conducive to bacterial proliferation. Although the heating zone reaches relatively high temperatures, the spiral discharge channel is not fully submerged in water, resulting in an actual temperature that falls below the level required for effective disinfection and thus fails to adequately kill bacteria.
Scale buildup: The surface of the spiral discharge channel tends to become heavily coated with scale. Not only is this scale difficult to clean, but it also provides a perfect hiding place for bacteria. During the washing process, fabrics come into contact with these scaled surfaces, increasing the risk of bacterial contamination.
Microbiological indicators fail to meet the standards: According to the WS/T 508—2016 standard, after medical textiles are washed, neither Escherichia coli nor Staphylococcus aureus should be detectable, and the total colony count must also comply with the specified requirements. However, the internal structure of tunnel-type washing machines cannot effectively disinfect, which may result in these pathogens remaining on the textiles and failing to meet the standard requirements.
Real-world situation: In actual operation, even if the washing solution is at a relatively high temperature, the temperature of the spiral discharge channel still isn't sufficient to kill bacteria. Consequently, as fabrics pass through this channel, they may become contaminated by residual bacteria, resulting in the washed fabrics failing to meet microbiological standards.
In summary, the design and operating conditions of tunnel-type washing machines make it difficult for them to meet the stringent microbial standards required in medical laundry facilities. The through-flow nature of their internal structure and the humid, warm environment provide ideal conditions for bacterial proliferation. Moreover, the insufficient temperature and accumulation of scale in the spiral discharge channels further exacerbate this issue. Consequently, when used in medical laundry facilities, these machines pose a high risk of bacterial contamination and fail to comply with the microbial standards specified in WS/T 508—2016.