Identification of specific spoilage microorganisms of fresh cut pineapple and effects of antimicrobial active packaging

The main purpose of this work is to investigate the effective antimicrobial efficacy of carvacrol and cinnamaldheyde against Pichia guillermondii. The choice of this microorganism has been made because it is one of the main spoilage yeasts traced in fruit and vegetable products, especially those with high humidity such as pineapple. In the first part of the work, the efficacy of different concentrations of carvacrol and cinnamaldehyde released from active sachets was evaluated in vitro at three different temperatures 23°C, 10°C and 5°C. To assess the exact population of fresh cut pineapple, taxonomic characterization will be also performed after yeasts isolation, DNA extraction and 26S rDNA sequencing. Afterwards, an in vivo test on fresh-cut pineapple using carvacrol and cinnamaldheyde emitters was carried out. The action of the active substances were tested not only against yeasts, including Pichia guillermondii, but also on the aerobic microflora (CBT), molds and pseudomonads originally present on the raw surface of pineapple. The test on the food system was also targeted to evaluate the synergistic effect of the antimicrobial concentration and temperature. In fact, the experimental plan related to the shelf life test was carried out using two different temperatures: 4°C throughout the test and an abuse temperature that consisted in storing the product at 4°C for different times followed by 2 days at 10°C. During the test, physical, chemical and microbiological analyses were performed. The experiments highlighted the ability of low concentration of carvacrol and cinnamaldehyde in reducing the growth of yeasts, maintaining the quality parameters in terms of texture and color within acceptability limits.