Can sushi contain pathogens or parasites that can cause asymptomatic colonization in the gastrointestinal (GI) tract?

From the Guidelines

Raw or undercooked sushi can contain pathogens or parasites that can cause asymptomatic colonization in the gastrointestinal (GI) tract, and individuals should exercise caution when consuming it, especially if they have compromised immune systems. When considering the risk of asymptomatic colonization from sushi, it's essential to note that proper food handling and preparation can significantly reduce this risk. According to guidelines for food safety 1, it's crucial to handle raw meats, fish, poultry, and eggs with special care, thoroughly cleaning all utensils, countertops, cutting boards, and sponges that have contacted raw meat, and keeping raw meats and ready-to-eat foods separate. Key points to consider when evaluating the safety of sushi include:

• The risk of bacterial contamination, such as from Vibrio or other pathogens, which can be mitigated by proper handling and storage of sushi-grade fish
• The potential for parasitic infection, such as from Anisakis, which can be killed by freezing the fish before consumption
• The importance of consuming sushi from trusted sources that follow proper food safety protocols, including freezing fish before use and handling it hygienically
• The consideration that regular consumption of raw fish may slightly increase the risk of harboring certain parasites, particularly if the fish hasn't been properly frozen, as noted in general guidelines for food safety 1. Given these considerations, individuals can enjoy properly prepared sushi without significant health concerns, but it's crucial to prioritize food safety and handle raw or undercooked sushi with caution.

From the Research

Microbiological Hazards in Sushi

• Sushi can contain pathogens or parasites that can cause asymptomatic colonization in the gastrointestinal (GI) tract, as it is a traditional Japanese food that mostly consists of rice and raw fish 2.
• The consumption of raw muscle incurs potential health risks such as ingestion of pathogenic bacteria or parasites, including Escherichia coli, Staphylococcus aureus, Salmonella, and Listeria monocytogenes 2, 3.
• Ready-to-eat raw fish containing products, such as sushi and sashimi, can pose biological and chemical hazards, including contaminants that accumulate in edible tissue of fish and transmit to humans via the food chain 4.

Risk of Parasitic Infections

• Using raw fish to make sushi may pose a risk of certain parasitic infections, such as anisakidosis, which is most reported in Japan 5.
• Freezing fish can eliminate the risk of anisakidosis, but it is believed by some that freezing ruins sushi's taste, although studies have shown that this is not the case 5.

Microbiological Quality of Sushi

• The microbiological quality of industrially processed sushi is higher than that of freshly prepared sushi, with aerobic mesophilic bacteria counts differing between frozen and fresh sushi 2.
• The quality of freshly prepared sushi strongly depends on the skills and habits of the preparation cooks, which may vary, and poor temperature control during distribution and display in stores can lead to reduced microbiological quality 2, 6.
• Potentially pathogenic bacteria, such as mesophilic Aeromonas spp. or bacteria belonging to the Enterobacteriaceae, can be introduced into sushi through both raw vegetables and fish 6.