Survival of <i>Listeria</i> Strains and Shelf Life Determination of Fresh Blueberries (<i>Vaccinium corymbosum</i>) Treated with Cold Atmospheric Plasma

oleh: Anibal A. Concha-Meyer, Alexandra González-Esparza, Patrick J. Cullen, Felipe Veloso, Mario Favre, Julio C. Valenzuela, Lorena Toloza, Brendan A. Niemira

Format: Article
Diterbitkan: MDPI AG 2024-03-01

Deskripsi

Fresh blueberries are delicate, hand-picked, packaged, and refrigerated fruits vulnerable to spoilage and contamination. Cold atmospheric plasma (CAP) is a promising antimicrobial technology; therefore, this study evaluated the CAP treatment effect on acid-tolerant <i>Listeria innocua</i> and <i>Listeria monocytogenes</i> and evaluated changes in the quality of the treated fruit. Samples were spot-inoculated with pH 5.5 and 6.0 acid-adapted <i>Listeria</i> species. Samples were treated with gliding arc CAP for 15, 30, 45, and 60 s and evaluated after 0, 1, 4, 7, and 11 days of storage at 4 °C and 90% humidity for the following quality parameters: total aerobic counts, yeast and molds, texture, color, soluble solids, pH, and titratable acidity. CAP treatments of 30 s and over demonstrated significant reductions in pathogens under both the resistant strain and pH conditions. Sixty-second CAP achieved a 0.54 Log CFU g<sup>−1</sup> reduction in <i>L. monocytogenes</i> (pH 5.5) and 0.28 Log CFU g<sup>−1</sup> for <i>L. monocytogenes</i> (pH 6.0). Yeast and mold counts on day 0 showed statistically significant reductions after 30, 45, and 60 s CAP with an average 2.34 Log CFU g<sup>−1</sup> reduction when compared to non-CAP treated samples. Quality parameters did not show major significant differences among CAP treatments during shelf life. CAP is an effective antimicrobial treatment that does not significantly affect fruit quality.