E. coli Is a Poor End-Product Criterion for Assessing the General Microbial Risk Posed From Consuming Norovirus...

Area of Science:

• Environmental microbiology
• Food safety
• Public health

Background:

• * Escherichia coli (E. coli) serves as a fecal indicator organism (FIO) for sewage contamination and shellfish depuration.
• * Assessing the effectiveness of current shellfish safety protocols is crucial for public health.

Purpose of the Study:

• * To evaluate the accumulation, retention, and depuration of non-pathogenic E. coli, pathogenic E. coli O157:H7, and norovirus GII (NoV GII) RNA in mussels.
• * To determine the immediate threat posed by combined sewer overflow (CSO) events to shellfish harvesting areas.
• * To assess the adequacy of current European Union (EU) standards for shellfish microbiological risk evaluation.

Main Methods:

• * Mussels (Mytilus edulis) were exposed to human fecal-contaminated water simulating a CSO event.
• * Accumulation, retention, and depuration of E. coli and NoV GII RNA were monitored.
• * A combination of culture-based and molecular methods was employed for microbial analysis.

Main Results:

• * All three indicators (non-pathogenic E. coli, pathogenic E. coli O157:H7, and NoV GII RNA) rapidly accumulated in mussels within 3 hours.
• * Depuration for 72 hours partially removed E. coli but did not eradicate NoV GII RNA.
• * Short CSO discharges represent an immediate risk to shellfish harvesting areas.

Conclusions:

• * Current EU standards for shellfish microbiological risk are inadequate for protecting consumers from NoV GII exposure.
• * Norovirus GII poses a significant risk in shellfish harvested from polluted marine waters.
• * Further evaluation of shellfish safety protocols is necessary to address viral contamination risks.