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Product shelf life dates may be unacceptable.

New research on untreated green olives has found that products with a stated shelf life of two to three years can be unacceptable long before their sell-by date. The study, published in the Journal of the Science of Food and Agriculture by scientists at the National Agricultural Research Foundation of Greece, examined the growing trend toward using polyethylene pouches, which are vacuum-packed, filled with brine or packed in modified atmospheres to extend shelf life.

Only the vacuum pouches gave promising results, producing a shelf life of nearly two years, while those products packed in ordinary air had a true shelf life of only nine months. The author of the study, Dr. Efstathios Panagou, points out that the stated shelf life on new packaging is not clearly defined, quite arbitrary and may not be supported by relevant studies.

About 1 million tons of olives are consumed each year worldwide, and most are produced in the European Union. Untreated green olives are valued for their superior flavor, but very little research has been done on the way their quality declines after they are packaged. Dr. Panagou's research looked at different packing methods over a six-month period, testing the olives for microorganisms, acidity, color and firmness. A 10-member expert panel then rated the product on smell, taste and general acceptability.

Researchers examined olives that had been placed in different kinds of brine, in air, in vacuum and in a modified atmosphere of 40% carbon dioxide, 30% nitrogen and 30% oxygen environments. No harmful bacteria was found in any of the olives after six months of storage at room temperature, but the overall quality of taste, smell, color and firmness was found to be unacceptable in the air-packed olives and those packed in a modified atmosphere. There was only medium acceptability for product packed in brine. The shelf life findings:

* Air: suggested shelf life--nine months;

* Modified atmosphere: suggested shelf life--15 months; and

* Vacuum: suggested shelf life--23 months.

Details. Efstathios Z. Panagou. Effect of different packing treatments on the microbiological and physiochemical characteristics of untreated green olives of the Conservolea cultivar. Journal of the Science of Food and Agriculture. Vol. 84 (online);

More information. Efstathios Panagou, National Agricultural Research Foundation, Institute of Technology of Agricultural Products, 1, Sof. Venizelou str., Lycovrissi, Greece, GR-141 23; phone: +30-210-2845940; fax. +30-210-2840740; email:
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Publication:Emerging Food R&D Report
Date:May 1, 2004
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