Combinations of Antimycotics to Inhibit the Growth of Molds Capable of Producing 1,3-Pentadiene in Foods and Beverages

Summary

Some strains of molds and yeasts are capable of degrading potassium sorbate, a chemical preservative used to prevent their growth in foods. One of the breakdown products of this degradation is 1,3-pentadiene, a volatile compound with an odor described as being similar to that of kerosene, acrylic paint, or petroleum products. A study was done to determine the effectiveness of alternative antimycotics to control the growth of five species of molds. Parmesan cheese and a lemon-flavored drink were used as model test systems. Results show that food preservative systems containing a reduced concentration of sorbate, in combination with other antimycotics, have potential for controlling the growth of molds capable of producing 1,3-pentadiene.

Situation

Raw and pasteurized foods and beverages as well as products subjected to more rigorous thermal processes, e.g., hot-fill beverages, may contain a wide range of molds. These molds may grow during the expected shelf life of these products to cause visual spoilage or result in the production of volatile compounds that are offensive to the consumer. Some of the molds known to grow in the presence of potassium sorbate can produce mycotoxins, thereby posing a public health concern. Degradation of sorbate through decarboxylation by some species of molds and yeasts can result in the accumulation of 1,3-pentadiene, a volatile compound having an odor described as being similar to that of kerosene, acrylic paint, or petroleum products. While the control of these microorganisms in some types of foods and beverages may be achievable through the addition of high concentrations of the preservative, the adverse effect of off aromas and off flavors that may result make this approach impractical. Instead, the use of antimycotics other than sorbate, e.g., natamycin, ethylenediaminetetracetic acid, and propionate, or a low concentration of sorbate in combination with other antimycotics, may be options to prevent or retard the growth of 1,3-pentadiene-producing molds.

Response

The effectiveness of reduced concentrations of sorbate, in combination with other antimycotics, to control the growth of molds capable of producing 1,3-pentadiene was studied. We evaluated potassium sorbate, sodium benzoate, calcium propionate, disodium ethylenediaminetetraacetic acid (EDTA), and natamycin, alone and in combination, for their effectiveness in preventing the growth of five molds isolated from Parmesan cheese and a lemon-flavored drink subjectively judged to contain 1,3-pentadiene. Growth of Penicillium brevicompactum, Penicillium roqueforti, Paecilomyces variotii, Aspergillus niger, and Cephaloascus fragrans on Parmesan cheese (PRM) (pH 5.5) agar and lemon-flavored drink (LD) agar (pH 2.6) supplemented with antimycotics was studied.

Impact

All molds grew well at 21ºC on PRM agar containing potassium sorbate (3,500 ppm), calcium propionate (3,000 ppm), or natamycin (20 ppm). Combinations of potassium sorbate (250 - 1,000 ppm), calcium propionate (250 - 1,000 ppm), and/or natamycin (10 - 18 ppm) greatly inhibited or prevented growth of molds on PRM agar, indicating their potential as preservative systems at pH values resulting in large percentages of the acids in dissociated forms. Three of the five molds grew on LD agar containing potassium sorbate or sodium benzoate at a concentration of 200 ppm. Growth did not occur within 70 days on LD agar containing EDTA (30 ppm) in combination with potassium sorbate and sodium benzoate at 50 and 175 ppm, respectively, or 175 and 50 ppm, respectively. Results of this study show that preservative systems containing a reduced concentration of potassium sorbate, in combination with other antimycotics, have potential for controlling the growth of molds capable of producing 1,3-pentadiene.

State Issue

Food Safety

Details

• Year: 2007
• Geographic Scope: International
• County: Spalding
• Unit, Department, or Group: Center for Food Safety
• Program Areas:
  • Agriculture & Natural Resources