Spanish slugs spread bacteria but vegetables remain safe with proper precautions

The invasive Spanish slug, now widespread across Finland, carries harmful bacteria into gardens, but vegetables untouched by the pest can still be eaten if thoroughly washed, according to Mia Kapanen, lead environmental health inspector in Jyväskylä.

Kapanen confirmed that while the slugs may contaminate produce with bacteria such as listeria or E. coli, unaffected vegetables pose no risk if cleaned properly. She emphasized that harmful bacteria are typically destroyed by cooking.

No health issues linked to the slugs have been reported to Jyväskylä’s environmental health authorities. Kapanen noted that tracing the source of infections like listeria—with an incubation period of up to three months—is difficult, as identifying the exact cause of illness is challenging.

Residents in affected areas, such as Mikkeli’s Otava district, report growing nuisance from the slugs. Satu Marja Tanttu, a local, collects liters of the pests daily during wet weather. She attributes the problem to poorly maintained city-owned land near her home, where the slugs thrive.

The Spanish slug, classified as a nationally harmful invasive species in Finland, can grow up to 14 centimeters in length.