African Journal of
Microbiology Research

  • Abbreviation: Afr. J. Microbiol. Res.
  • Language: English
  • ISSN: 1996-0808
  • DOI: 10.5897/AJMR
  • Start Year: 2007
  • Published Articles: 5137

Full Length Research Paper

Shelf stability of processed cocoyam flour during storage at room temperature (28.0 ± 2°C) for a period of four months

G. I. Okwu
  • G. I. Okwu
  • Department of Microbiology, Ambrose Alli University, Ekpoma, Edo State, Nigeria.
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A. R. Akpe
  • A. R. Akpe
  • Department of Microbiology, Ambrose Alli University, Ekpoma, Edo State, Nigeria.
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A. A. Osawaru
  • A. A. Osawaru
  • Department of Microbiology, Ambrose Alli University, Ekpoma, Edo State, Nigeria.
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  •  Received: 18 August 2020
  •  Accepted: 08 December 2020
  •  Published: 30 June 2021

Abstract

The shelf life study of dry milled cocoyam flour packaged in low density polyethylene was carried out for a period of 4-month. Microbiological, nutritional, physicochemical quality characteristics and aflatoxin content were evaluated. The total viable bacterial counts  ranged from 1.6×103 - 4.8×105 cfu/g while the total viable fungal count increased from 5.0 × 101 - 3.8 × 105 sfu/g. The bacteria isolated include Bacillus species, Bacillus subtilis, Proteus species, Staphylococcus epidermidis, Streptococcus pyogenes, Micrococcus luteus, Klebsiella species, Staphylococcus aureus, Pseudomonas species and Staphylococcus saprophytic. Fungal genera isolated include Penicillum species, Aspergillus flavus, Aspergillus niger, Fusarium, Mucor and Rhizopus species. Gradual decrease in pH (6.40 ± 0.001 to 4.17± 0.01) and noticeable increase in titrateable acidity (0.024 ± 0.003 to 1.17 ± 0.01%) were observed during storage. There was an increase in moisture content while carbohydrate, protein, fat, crude fibre and ash were found to decrease during storage. Aflatoxin B1 and B2 content from 0 h to the 4th month were (0.020, 0.006) and (0.097, 0.063) µg/kg respectively. The presence of aflatoxin B1 and B2 is of public health concern. There is need for improved processing, handling techniques and good hygiene practices to ensure safety of the finished product.

 

Key words: Cocoyam, shelf life, room temperature, aflatoxin content, nutritional analysis.