title: Effect of postharvest practices including degreening on citrus carpoplane microbial biomes.
abstract: OBJECTIVE
  To investigate the effect of commercial citrus packhouse processing steps on the fruit surface microbiome of Clementines and Palmer navel oranges.
  
  
  RESULTS
  Viable bacteria, yeast and fungi counts, and the pyrosequencing analysis of the 16S rRNA and ITS were used to evaluate the community structure and population dynamics of phylloepiphytic bacteria and fungi associated with commercial postharvest processing. Drenching significantly reduced microbial counts in all cases except for yeasts on navels, while the extent of degreening effects varied between the citrus varieties. Pyrosequencing analysis showed a total of 4409 bacteria and 5792 fungi nonchimeric unique sequences with an average of 1102 bacteria and 1448 fungi reads per sample. Dominant phyla on the citrus carpoplane were Proteobacteria (53·5%), Actinobacteria (19·9%), Bacteroidetes (5·6%) and Deinococcus-Thermus (5·4%) for bacteria and Ascomycota (80·5%) and Basidiomycota (9·8%) for fungi. Beginning with freshly harvested fruit fungal diversity declined significantly after drenching, but had little effect on bacteria and populations recovered during degreening treatments, including those for Penicillium sp.
  
  
  CONCLUSIONS
  Packhouse processing greatly influences microbial communities on the citrus carpoplane.
  
  
  CONCLUSIONS
  A broad orange biome was described with pyrosequencing and gave insight into the likely survival and persistence of pathogens, especially as they may affect the quality and safety of the packed product. A close examination of the microbiota of fruit and the impact of intervention strategies on the ecological balance may provide a more durable approach to reduce losses and spoilage.
authors.affiliation: Department of Plant and Soil Sciences, University of Pretoria, Hatfield, South Africa.
authors.forename: A
authors.initials: A
authors.lastname: Gomba
authors.affiliation: Department of Plant and Soil Sciences, University of Pretoria, Hatfield, South Africa.
authors.forename: L
authors.initials: L
authors.lastname: Chidamba
authors.affiliation: Department of Plant and Soil Sciences, University of Pretoria, Hatfield, South Africa.
authors.forename: L
authors.initials: L
authors.lastname: Korsten
mesh_terms: D001419:Bacteria / Q000235:genetics / Q000302:isolation & purification*; D032084:Citrus sinensis / Q000382:microbiology*; D005511:Food Handling; D005638:Fruit / Q000382:microbiology*; D005658:Fungi / Q000235:genetics / Q000302:isolation & purification*; D064307:Microbiota; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D012336:RNA, Ribosomal, 16S
keywords: bacteria; citrus biome; degreening; drenching; fungi yeast; pyrosequencing