Sensitive Detection of Foodborne Parasitic Larvae Using a Sieving-qPCR Workflow: Application to Angiostrongylus...

Area of Science:

• Veterinary Parasitology
• Food Safety Science
• Molecular Diagnostics

Background:

• Angiostrongylus cantonensis is a parasitic nematode with zoonotic potential, posing risks through contaminated food and water.
• Current environmental surveillance for A. cantonensis is limited by the lack of simple and reliable screening methods.

Purpose of the Study:

• To evaluate and optimize methods for detecting Angiostrongylus cantonensis DNA in lamb's lettuce (Valerianella locusta).
• To establish a sensitive detection limit for A. cantonensis larvae in vegetable samples.

Main Methods:

• Comparison of three larval concentration methods (sedimentation, two sieving techniques) from water samples.
• Assessment of two DNA extraction modifications on spiked lettuce samples.
• Evaluation of detection limit using quantitative polymerase chain reaction (qPCR) on lettuce spiked with varying numbers of third-stage larvae (L3).

Main Results:

• A sieving method combined with direct sieve DNA extraction yielded the highest DNA recovery.
• The optimized method achieved a detection limit of a single L3 in 50g of lamb's lettuce.
• Successful DNA detection was achieved from both sieve-retained material and flow-through.

Conclusions:

• Sieving techniques combined with sensitive qPCR offer a promising approach for screening parasite larvae, like A. cantonensis, in vegetables.
• This method supports food safety monitoring by indicating potential health risks associated with contaminated produce.
• The technique is adaptable for detecting parasites in other vegetables.