13.4.1   Biotic changes and their causal factors
During transport, handing and storage, the goods are under the influence of the environment with which they correlate (interact) and consequently undergo biotic changes, of which the most important are:
  • Changes due to microorganisms (molds, bacteria, yeasts), which lead to mold growth and rot
  • Metabolic processes in the case of organs and organisms, such as respiration, glycolysis, autolysis
  • Other biochemical changes, such as rancidity, fermentation, self-heating
  • Changes due to animal pests, such as insects (beetles, moths), arachnids (mites) and rodents (rats, mice)
The causal factors are:
  • Mechanical influences (throwing, dropping, impacts, jolting), which cause bruises on fruit and vegetables, which in turn act as starting points for microbial attack
  • Elevated temperatures

    • promote the growth and multiplication of microorganisms to their optimum extent
    • encourage animal pests to become active, up to their maximum level of mobility
    • additionally activate metabolic processes in goods of vegetable origin

  • Relatively low temperatures, which cause chilling damage (chilling) in fruit and vegetables, if the temperature falls below the lower temperature limit admissible for a specific product, e.g. brown spot diseases, loss of ability to ripen
  • High water content or high relative humidity, which in particular promotes growth of microorganisms
  • Influence of air composition (e.g. atmospheric oxygen, carbon dioxide, ethylene), which affects the respiration and ripening of goods of vegetable origin (allelopathy)
  • Air movement, dust and microbe content of air, all of which promote infection by microorganisms

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