Effectiveness of immersion treatments with acids, trisodium phosphate, andherb decoctions in reducing populations of Yarrowia lipolytica and naturally occurring aerobic microorganisms on raw chicken

Yarrowia lipolytica, one of the predominant yeasts in raw poultry, is belie ved to play a role in spoilage. This study was undertaken to investigate tr eatments to control the growth of Y. lipolytica on raw chicken stored at re frigeration temperature. Raw chicken wings inoculated with a mixture of fiv e strains of Y. lipolytica isolated from raw poultry were dipped in solutio ns containing 2, 5, or 8% lactic acid, 2% lactic acid containing 0.2, 0.4, Or 0.8% potassium sorbate or sodium benzoate, and 4. 8, or 12% trisodium ph osphate solution. Populations of the yeast and total aerobic microorganisms were determined before and after treatment. immersion of wings in 2% lacti c acid (with or without 0.2% potassium sorbate or sodium benzoate) or 4% tr isodium phosphate caused a significant (alpha = 0.05) reduction in numbers of Y. lipolytica and aerobic microorganisms. Treatment with 2% lactic acid containing 0.4 or 0.8% preservative did not result in additional significan t reductions. Treatment of chicken wings with 2% lactic acid or 8% trisodiu m phosphate significantly reduced numbers of Y. lipolytica by 1.47 and 0.65 log(10) cfu/g, respectively, and aerobic microorganisms by 2.60 and 1.21 l og(10) cfu/g, respectively, compared to controls. Growth of Y. lipolytica o n wings stored at 5 degreesC for up to 9 days, however, was not affected by these treatments. Significant reductions in the population of Y. lipolytic a occurred when the yeast was inoculated into 100% basil, marjoram, sage, a nd thyme decoctions, but not in 100% oregano or rosemary decoctions, held a t 5 degreesC for 24 h. Treatment of chicken wings with 100% sage or thyme d ecoctions significantly reduced populations of Y. lipolytica but did not co ntrol its growth during storage at 5 degreesC for up to 9 days. The small. temporary decreases in numbers of Y. lipolytica and aerobic microorganisms resulting from immersion treatment of chicken wings with sage and thyme dec octions render these treatments of questionable value as preservation inter ventions. (C) 2001 Elsevier Science B.V. All rights reserved.