`Researchers Detect Microplastics in Italian Olive Oils Using New Imaging Technique - Olive Oil Times
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Researchers Detect Microplastics in Italian Olive Oils Using New Imaging Technique

By Paolo DeAndreis
Dec. 15, 2025 15:23 UTC
Summary Summary

Researchers at the University of Florence found microplas­tics in Italian extra vir­gin olive oils using an inno­v­a­tive imag­ing tech­nique, with con­cen­tra­tions vary­ing widely among sam­ples. The study sug­gests that the sup­ply chain length may be a sig­nif­i­cant fac­tor in microplas­tic con­t­a­m­i­na­tion, with fur­ther research needed to iden­tify sources and reduce lev­els in olive oil pro­duc­tion.

Microplastics have been detected in some Italian extra vir­gin olive oils by a team of researchers at the University of Florence.

By ana­lyz­ing a lim­ited num­ber of prod­ucts using an inno­v­a­tive imag­ing tech­nique never pre­vi­ously applied to olive oil, the researchers were able to mea­sure the quan­tity, shape and char­ac­ter­is­tics of microplas­tic par­ti­cles.

While we found microplas­tics in olive oil, these prod­ucts are not among the foods most exposed to microplas­tic con­t­a­m­i­na­tion.- Patrizia Pinelli, asso­ciate pro­fes­sor of com­mod­ity sci­ences at the University of Florence

Extra vir­gin olive oils col­lected for the study pub­lished in Food Chemistry con­tained microplas­tics in every sam­ple, although con­cen­tra­tions var­ied widely. Tuscan olive oils sourced from local mills ranged from about 10 to roughly 1,700 par­ti­cles per liter, with most sam­ples below 350 par­ti­cles per liter.

By con­trast, the two super­mar­ket olive oils labeled as ​“pro­duced in the E.U.” showed much higher lev­els, rang­ing from around 4,000 to more than 7,900 par­ti­cles per liter.

“Microplastics are ubiq­ui­tous; we inhale and ingest them every day. While we found microplas­tics in olive oil, these prod­ucts are not among the foods most exposed to microplas­tic con­t­a­m­i­na­tion,” Patrizia Pinelli, asso­ciate pro­fes­sor of com­mod­ity sci­ences at the University of Florence and co-author of the study, told Olive Oil Times.

Researchers cau­tioned that the observed dif­fer­ences do not con­sti­tute sta­tis­ti­cally robust evi­dence, as the ini­tial study ana­lyzed only a small num­ber of sam­ples: ten from local mills and two from large retail dis­tri­b­u­tion.

While future stud­ies will inves­ti­gate these dis­crep­an­cies fur­ther, the researchers sug­gested that sup­ply chain length is the most likely expla­na­tion.

“In large-scale retail olive oils labeled as E.U. ori­gin, olives may be har­vested in one coun­try and milled in another, or stored for much longer peri­ods. In Tuscany, trans­for­ma­tion from olive to oil usu­ally occurs within 24 to 48 hours. A longer sup­ply chain nat­u­rally increases con­t­a­m­i­na­tion oppor­tu­ni­ties,” Pinelli said.

In some cases, olive oils from the same mill con­tained markedly dif­fer­ent lev­els of microplas­tics. ​“This dif­fer­ence is most likely due to the dif­fer­ent ori­gin of the olives,” Pinelli noted, adding that mate­ri­als used dur­ing milling are unlikely to be the pri­mary source of con­t­a­m­i­na­tion.

“A poly­mer can have mul­ti­ple sources, so fur­ther stud­ies are needed to iden­tify where these plas­tics orig­i­nate along the sup­ply chain. The mill should the­o­ret­i­cally be the least crit­i­cal point, but this needs ver­i­fi­ca­tion,” Pinelli explained.

“A sig­nif­i­cant por­tion of con­t­a­m­i­na­tion likely orig­i­nates in the field due to the increased use of mech­a­nized equip­ment, nets and poly­mer-based tools,” Chiara Vita added.

Researchers expected to find microplas­tics in olive oil, as such par­ti­cles are now wide­spread in air, water and agri­cul­ture, and their pres­ence in food and bev­er­ages is well estab­lished.

“The main expo­sure of the gen­eral pop­u­la­tion to microplas­tics likely comes from sources such as bot­tled water or seafood,” Riccardo Gori, asso­ciate pro­fes­sor of san­i­tary and envi­ron­men­tal engi­neer­ing at the University of Florence and co-author of the study, told Olive Oil Times.

Vita, an asso­ciate researcher at the University of Florence’s Prato Campus (PIN Foundation), added that ​“other foods show far higher lev­els.”

“Some shrimp sam­ples report around ten par­ti­cles per gram, while for olive oil we are talk­ing about 60 to 70 par­ti­cles per kilo­gram. Table salt also con­tains sig­nif­i­cant quan­ti­ties of microplas­tics,” she said.

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Researchers also noted that olive oil con­sump­tion vol­umes are rel­a­tively small. ​“The rec­om­mended intake of olive oil accord­ing to the European Food Safety Authority is 30 to 50 grams per day, far below water con­sump­tion, which fur­ther reduces effec­tive expo­sure,” Vita said.

“In risk assess­ment, con­cen­tra­tion is only one part of the equa­tion. What mat­ters is how much is ingested rel­a­tive to body weight,” Gori added.

To detect and char­ac­ter­ize microplas­tics, the team used Laser Direct InfraRed (LDIR) spec­troscopy, a tech­nique com­bin­ing Quantum Cascade Laser tech­nol­ogy with rapid opti­cal scan­ning to gen­er­ate vis­i­ble and infrared images.

The method mea­sures par­ti­cle size, mor­phol­ogy and poly­mer com­po­si­tion, enabling auto­mated detec­tion of tiny par­ti­cles in com­plex lipid matri­ces such as extra vir­gin olive oil and reduc­ing sub­jec­tive visual selec­tion.

The tech­nol­ogy can detect plas­tics down to approx­i­mately 1/100 mm. According to the researchers, it enables reli­able analy­sis while avoid­ing con­t­a­m­i­na­tion from lab­o­ra­tory pro­ce­dures.

Blank sam­ples processed with­out olive oil con­tained only 8 to 16 par­ti­cles per liter, con­firm­ing min­i­mal back­ground con­t­a­m­i­na­tion. The method also achieved a recov­ery rate close to 96 per­cent.

Analysis iden­ti­fied eight dif­fer­ent poly­mers com­monly used in pack­ag­ing, agri­cul­tural tools and food-con­tact equip­ment. Most par­ti­cles mea­sured between 10 and 100 microm­e­ters, par­tic­u­larly in the 30 to 50 microm­e­ter range, and were mainly irreg­u­lar frag­ments rather than fibers or pel­lets.

Particle shape offers clues to con­t­a­m­i­na­tion sources, as irreg­u­lar frag­ments typ­i­cally result from abra­sion or break­age of plas­tic com­po­nents used dur­ing har­vest­ing, han­dling or pro­cess­ing.

A notable find­ing was the preva­lence of acry­loni­trile buta­di­ene styrene (ABS) in the two large retailer oils, account­ing for 49 per­cent and 93 per­cent of detected microplas­tics, respec­tively.

“ABS is rarely reported in food stud­ies, except for ref­er­ences to its use in irri­ga­tion sys­tems. This deserves fur­ther inves­ti­ga­tion,” Vita said.

The researchers empha­sized that the find­ings are pre­lim­i­nary. Future stud­ies will ana­lyze a broader range of olive oils to deter­mine whether sup­ply chain length con­sis­tently influ­ences microplas­tic con­t­a­m­i­na­tion.

Many olive oil pro­duc­ers are already work­ing toward fully sus­tain­able and eco-friendly pro­duc­tion chains.

“It will likely never be pos­si­ble to have com­pletely microplas­tic-free extra vir­gin olive oil. Microplastics are every­where, even in lab­o­ra­tory envi­ron­ments. However, we can reduce them to very low lev­els,” Vita con­cluded.

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