Synergistic effect of gamma irradiation and proper packaging for the control of insects in smoked shrimps (Penaeus notialis) from three different water bodies in Ghana

Abstract

Damage caused to stored dried shrimps by insect pests is problematic and are often underestimated. The incubation, identification, and control of these insect pests which infest shrimps from three water sources; sea, lagoon, and river were evaluated according to standard procedures of the Entomological Society of Canada. Exposure to gamma ionizing radiation was undertaken from a Cobalt 60 source (SL 515, Hungary) and radiation doses of 0, 4, 8, and 10 kGy at a rate of 1.7 kGy/hr were used. The hidden insects identified were Necrobia rufipes (Copra beetle), Dermestes maculatus De Geer (Hide beetle), and a mite Lardoglyphus sp. belonging to the family Acaridae in the mite group Astigmata. An after-feeding test on shrimps by insects revealed a weight reduction by 17%, 14%, and 26% for sea, lagoon, and riverine shrimps respectively. These observations were statistically significant at p ≤ 0.05 level. After 2 months of storage there was generally a 43.0 % reduction in weight which was significantly different (p ≤ 0.05) from the initial weight. Moisture sorption isotherms of dehydrated shrimps were also checked at 20, 55, 65, 75, 85, and 95% of Effective Relative Humidity (EHR) and revealed a general trend of sigmoid shape. The prescribed dose of 8–10 kGy was able to kill all insects and rendered the product insect-free in airtight dense polypropylene containers used in these investigations.

Keywords:

• insects
• dried shrimps
• Penaeus notialis
• gamma irradiation
• moisture isotherms
• Ghana

PUBLIC INTEREST STATEMENT

Shrimp meat consumption is extensively accepted (globally) according to FAO in 2010 due to its enormous nutritional as well as health benefits. Shrimp is in high demand owing to its use in the preparation of several scrumptious dishes. Shrimp has helped alleviate food crises and protein malnutrition in many developing countries, providing a valuable supplement to a diverse and nutritious diets. Shrimp meat acquisition and consumption has not been widely studied. Studies investigating the preservation of these shrimps using an effective monitoring of the moisture absorbed by the shrimps stored in air-tight polypropylene packages which is anticipated to discourage the growth of microorganisms and larval infestations was carried out. Gamma irradiation which is a non-thermal means of preservation of food, with ionizing radiations was also employed to augment the preservation and shelf life extension of the shrimps in the polypropylene packaging material.

Competing Interests

The authors declares no competing interests.

Acknowledgements

Authors are grateful to Messrs S.N.Y. Annan, S.N.O. Armah and S.N.L.W. Mills of Radiation Technology Centre of Ghana Atomic Energy Commision (GAEC), Kwabenya, carried out the irradiation process. Also to Mr. George Akwetey and all staff of the Mycology Unit, Department of Plant and Environmental Biology, University of Ghana, for making available their equipment and materials for this study.

Author statement

This manuscript describes original work that has not been published elsewhere and is not under consideration by any other journal. All authors approved the manuscript and this submission.

Authors’contributions

The principal author (Felicia Akuamoa) was the one who conducted the laboratory analyses. She also researched on the topic and came out with the relevant literature for the write-up. The second author (George Tawia Odamtten) supervised the study from start to finish and he was also responsible for all the necessary corrections in the write-up. The third author (Nii Korley Kortei) assisted in carrying-out the experiment, assemblage of the write-up and making the needed corrections as well as submitting it to a suitable journal for publication. All authors read and approved the final manuscript.

Cover Image

Caption: A: photograph showing dehydrated-smoked shrimp placed in dense polypropylene bowl with lid eccentrically placed on top of the bowl (x 1/5).

A: Dorsal view: (larva of Dermestes maculatus DeGeer (Hide Beetle), B: Dorsal view: (Adult Dermestes maculatus DeGeer (Hide Beetle)), C: The vertical view (Adult Dermestes maculatus DeGeer (Hide Beetle)).

Additional information

Notes on contributors

Felicia Akuamoa

Mrs Felicia Akuamoa is an M.phil.(Radiation Processing) holder from University of Ghana. She is a Doctoral student at the Wageningen Agricultural University, Holland. She works as a Research Scientist at the Ghana Atomic Energy Commission. Her research areas include in-vitro antioxidant analysis and radiation processing of foods.

George Tawia Odamtten

Prof. George Tawia Odamtten holds a Ph.D in Agriculture & Food Safety from the Wageningen Agricultural University, Holland. He is a Full Professor of Mycology and Plant Pathology at University of Ghana. His research areas include fungal pathogens of crops, food borne fungal contaminants, fungal biotechnology and mycotoxin analysis.

Nii Korley Kortei

Dr. Nii Korley Kortei holds a Ph.D in Radiation Processing (Food Science option) from the University of Ghana. He is a Senior Lecturer of Food Science at the Department of Nutrition and Dietetics, University of Health and Allied Sciences, Ghana. His research areas are food borne fungal contaminants, mycotoxins, myco-chemicals in foods, and risk assessment of mycotoxins via food consumption.