Spain Tackles the Salty Truth About Table Olives

A research ini­tia­tive in Spain com­pris­ing sci­en­tists from the Andalusian Institute of Agricultural and Fisheries Research and Training (IFAPA) and mem­bers of the olive indus­try is attempt­ing to develop viable meth­ods for reduc­ing sodium usage in table olive pro­duc­tion.

The project, launched in 2023, seeks to for­mu­late guide­lines for olive pro­cess­ing that sig­nif­i­cantly reduce salt lev­els. This would reduce efflu­ent con­t­a­m­i­na­tion while gen­er­at­ing a health­ier prod­uct closer to the World Health Organization (WHO) salt con­sump­tion rec­om­men­da­tions.

New tech­niques are being researched and tri­aled to achieve this goal. The Andalusian regional gov­ern­ment plans to pub­lish the results on its web­site.

At the begin­ning of December, a series of con­fer­ences was held in the munic­i­pal­ity of Arahal, Seville, in which the results of tests car­ried out with olives from the pre­vi­ous sea­son were pre­sented and eval­u­ated.

The main topic of the dis­cus­sion was the chal­lenges posed by reduc­ing the use of salt dur­ing the brin­ing process.

In addi­tion, a tast­ing ses­sion of sea­soned olives fer­mented in low-salt brines was held, allow­ing the par­tic­i­pants to assess the results of var­i­ous tech­niques from a consumer’s per­spec­tive.

Salt plays an inte­gral role in the pro­duc­tion of table olives, with 6.6 met­ric tons being used per 1,000 tons of olives, serv­ing as a key com­po­nent of the fer­men­ta­tion and preser­va­tion processes.

Fermentation involves man­ag­ing saline solu­tions and pH lev­els to encour­age ben­e­fi­cial micro­bial activ­ity.

The process passes through dis­tinct phases, start­ing with the ini­tial pH reduc­tion by gram-neg­a­tive bac­te­ria and cul­mi­nat­ing in the dom­i­nance of lac­to­bacilli, which sta­bi­lize the prod­uct.

Maintaining proper salt con­cen­tra­tions pre­vents spoilage, such as the Zapatera effect caused by improper fer­men­ta­tion. This effect is so named because it has a dis­tinc­tive odor akin to wet shoe leather.

However, its use entails envi­ron­men­tal risks, as brine waste is a major pol­lu­tant. Industrial dis­charges have par­tic­u­larly affected the Guadaíra River in Andalusia, result­ing in eco­log­i­cal dam­age such as mass fish deaths and foam pol­lu­tion. The high salin­ity and organic load in olive-pro­cess­ing efflu­ents make the indus­try a focal point for envi­ron­men­tal con­cerns.

Table olives con­sti­tute the high­est export vol­ume among Spanish pre­served veg­etable prod­ucts and the high­est vol­ume by domes­tic con­sump­tion.

Table olives con­tain approx­i­mately four grams of salt per 100 grams of prod­uct. Current WHO guide­lines rec­om­mend a daily sodium intake below two grams, the equiv­a­lent of five grams of salt.

From a health per­spec­tive, this sig­nif­i­cant sodium con­tent con­tributes to exces­sive daily intake, which is asso­ci­ated with hyper­ten­sion, car­dio­vas­cu­lar dis­eases and other health risks.

With nearly 16.5 per­cent of Spain’s pop­u­la­tion expe­ri­enc­ing hyper­ten­sion, reduc­ing sodium in food prod­ucts such as olives is seen as a pub­lic health pri­or­ity.

Most cur­rent tech­niques for pro­duc­ing reduced-sodium table olives involve par­tially replac­ing sodium chlo­ride with alter­na­tive salts such as potas­sium chlo­ride or cal­cium chlo­ride.

Calcium chlo­ride, in par­tic­u­lar, is noted for impart­ing addi­tional bit­ter­ness to an already bit­ter prod­uct.

Given the Spanish pop­u­la­tion’s wide­spread and well-estab­lished con­sump­tion of olives, such defects are widely deemed unac­cept­able despite the poten­tial envi­ron­men­tal and health ben­e­fits.

• Junta de Andalucía
• IFAPA
• INIA