Fustiness, Rancidity Are the Most Common Defects in World Competition Submissions

Fustiness and ran­cid­ity were the two most com­mon defects detected by the analy­sis team at the 2024 NYIOOC World Olive Oil Competition.

Data pub­lished on the Olive Oil Times World Ranking plat­form show that 278 sam­ples sub­mit­ted to the com­pe­ti­tion con­tained fusti­ness, rep­re­sent­ing 44 per­cent of total defect occur­rence. Meanwhile, ran­cid­ity was detected in 172 sam­ples for 27 per­cent of the total defect occur­rence.

Overall, the panel of experts iden­ti­fied 627 occur­rences of seven defects in the olive oils sub­mit­ted to the com­pe­ti­tion. Notably, a sin­gle olive oil sam­ple can con­tain mul­ti­ple defects. More than ten per­cent of the entries sent to the NYIOOC were defec­tive.

To meet the stan­dards of the extra vir­gin grade, a sam­ple must be free of defects. These defects neg­a­tively impact the organolep­tic qual­ity of the olive oil and usu­ally reduce its health ben­e­fits.

While fusti­ness and ran­cid­ity were by far the most com­mon defects iden­ti­fied by the judges, sam­ples also con­tained winey (64), musti­ness (58), muddy sed­i­ment (33), heated or burned (20) and metal­lic (two) defects. According to the International Olive Council, 16 dif­fer­ent olive oil defects exist.

Expert olive oil tasters often iden­tify fusti­ness in sam­ples by detect­ing sen­sory attrib­utes such as tape­nade, olive mill waste­water and ripe olive fla­vors.

The pres­ence of fusti­ness often indi­cates that har­vested olives were stored for an extended period before milling into olive oil.

This delay trig­gers anaer­o­bic fer­men­ta­tion in the olives, lead­ing to unde­sir­able micro­bial activ­ity and the pro­duc­tion of dif­fer­ent acids.

Fustiness can also result from poor mill con­di­tions; olive oil can acquire this attribute when it comes into con­tact with old olive paste on inad­e­quately cleaned equip­ment.

According to Donato Palancia, ole­ol­o­gist and olive oil tech­ni­cian at Farchioni Olii, which earned three Gold Awards at the 2024 NYIOOC, milling tem­per­a­tures can exac­er­bate defects, includ­ing fusti­ness.

“The defect can be wors­ened dur­ing the extrac­tion phase by apply­ing exces­sively high tem­per­a­tures,” he said. ​“This often occurs in olive mills because higher tem­per­a­tures yield a greater quan­tity of olive oil from the olive paste.”

“However, these tem­per­a­tures com­pro­mise the qual­ity and sen­sory pro­file of the olive oil,” Palancia added. ​“Regardless of the sce­nario, a defect like this is very unlikely to be caused by ship­ping an olive oil sam­ple or bot­tle. It does not arise from trans­port.”

Meanwhile, ran­cid­ity is caused by the oxi­da­tion of olive oil and can occur dur­ing the extrac­tion phase and after the oil is pro­duced. Still, ​“a freshly-pro­duced olive oil is unlikely to oxi­dize quickly,” Palancia said.

Oxidation occurs when olive oil mol­e­cules inter­act with oxy­gen. While pro­tected by the antiox­i­dant prop­er­ties of cer­tain polyphe­nols, extra vir­gin olive oil is still sub­ject to degra­da­tion through oxi­da­tion.

Oxygen trig­gers the for­ma­tion of per­ox­ides, which react with unsat­u­rated fatty acids, the most abun­dant com­po­nents in olive oil, form­ing hydroper­ox­ides. This process leads to the cre­ation of alde­hy­des and ketones, which cause ran­cid­ity.

“A defect can alter the qual­ity of olive oil to vary­ing degrees and inten­si­ties,” Palancia said. ​“When we talk about oxi­da­tion in olive oil sam­ples, it could be asso­ci­ated with issues dur­ing trans­porta­tion. For instance, if some of the sample’s con­tent leaks from the con­tainer, air gaps are present, and oxi­da­tion may occur.”

Producers can detect defects and adjust accord­ingly in the milling phase of the olive oil pro­duc­tion process. As a result, Palancia believes pro­duc­ers should have a basic under­stand­ing of organolep­tic olive oil assess­ment.

“I would say that the tech­ni­cian of the olive oil mill resem­bles the direc­tor of an orches­tra,” Palancia said. ​“We have to try to har­mo­nize all the com­po­nents, like mak­ing a melody come out of an orches­tra, a melody able to char­ac­ter­ize the pro­duc­tion.”

“A taster with expe­ri­ence, who con­sis­tently tastes oils and under­stands the crops, ripeness and extrac­tion tech­niques, can rec­og­nize prob­lems,” he added. ​“That is not magic; it is the fun­da­men­tal expe­ri­ence needed for high-qual­ity olive oil pro­duc­tion.”