Radiation Physics and Chemistry 194 (2022) 110041 Available online 19 February 2022 0969-806X/© 2022 Elsevier Ltd. All rights reserved. Effect of gamma irradiation on shelf life of smoked guinea fowl (Numida meleagris) meat stored at refrigeration temperature Evelyn A. Otoo a , Fidelis C.K. Ocloo a, b, * , Victoria Appiah a a Department of Nuclear Agriculture and Radiation Processing, School of Nuclear and Allied Sciences, University of Ghana, Atomic Campus, P. O. Box AE 1, Atomic- Accra, Ghana b Radiation Technology Centre, Biotechnology and Nuclear Agriculture Research Institute, Ghana Atomic Energy Commission, P. O. Box LG 80, Legon, Accra, Ghana A R T I C L E INFO Keywords: Guinea fowl Smoking Gamma irradiation Shelf life Refrigeration ABSTRACT This study investigated the effect of gamma irradiation on shelf life of smoked guinea fowl meat stored at refrigerated temperature. Dressed guinea fowl meats were smoked, packaged and gamma irradiated at 2.5, 5.0 and 7.5 kGy with a dose rate of 0.74 kGy h  1 and compared with a control (un-irradiated). Physicochemical, sensory and microbial properties of the treated meats were determined over refrigerated storage period using appropriate procedures. Titratable acidity (TA) and acid value (AV) decreased significantly (p ≤ 0.05) with gamma irradiation, but increased with storage. pH of the meat samples were however within the neutral range which was numerically insignificant to affect quality characteristics of the processed meat. Bacterial isolates of natural microbiota identified on the basis of their mass spectra of protein profiles on the smoked guinea fowl meat were Staphylococcus aureus, Serratia marcescens and Enterobacter cloacae. The total bacterial counts (7.23 log 10 cfu/g) decreased with increasing doses of gamma irradiation and storage (1.29 log 10 cfu/g). Irradiation had highly significant effects (p ≤ 0.05) on the reduction of microbial population. Irradiation had no significant effects (p > 0.05) on the sensory attributes (aroma, colour, tenderness and taste) of the smoked guinea fowl meat; but the taste of the irradiated meat samples was influenced at the end of the seven weeks refrigerated storage period. Gamma irradiation has a potential to enhance shelf life of smoked guinea fowl meat at a refrigeration condition. 1. Introduction Guinea fowl meat has become a relishing meat in the diet of many health conscious individuals and for varying economic and socio- cultural use of the rural and peri-urban communities in Ghana, partic- ularly, the northern sector of the country (Teye and Adam, 2000). Guinea fowl meat is an excellent source of protein for humans as well as nutrient for the growth of both spoilage and pathogenic microbes (Adzitey et al., 2015). Smoking is one of the processing techniques used in extending shelf-life of guinea fowl meat. However, smoked guinea fowl meat has been found to be contaminated with microorganisms (Adzitey et al., 2015). These authors have reported the presence of bacteria species, namely Streptococcus, Proteus, Staphylococcus, Salmo- nella, Bacillus, Pseudomonas and Escherichia coli in some smoked guinea fowl meat samples sold in the Bolgatanga Municipality, Ghana (Adzitey et al., 2015). Due to the unique flavour and nutritional benefits of smoked guinea fowl meat, there is a need to adopt an innovative tech- nology in addition to smoking, to maintain and enhance the shelf life and safety status of guinea fowl meat. One of such technologies is the use of gamma irradiation. Gamma irradiation of food has been successful, not only in ensuring food safety, but in extending shelf life of meat and poultry products due to its effectiveness in inactivating pathogens without deteriorating product quality (Mahapatra et al., 2005). It is a safe technology for eradicating pathogens from raw and processed meat products for shelf life enhancement (Kong et al., 2017; Alfaia et al., 2007). Irradiation at a dose of up to 10 kGy has been used in animal products as an effective, safe and economical method of food preservation, posing no nutritional, toxicological or microbiological problems (O’bryan et al., 2008; WHO, 1999). Irradiation alone may not always be sufficient in achieving the intended effect. The dose required may produce undesirable sensory and * Corresponding author. Department of Nuclear Agriculture and Radiation Processing, School of Nuclear and Allied Sciences, University of Ghana, Atomic Campus, P. O. Box AE 1, Atomic-Accra, Ghana. E-mail addresses: fidocloo@gmail.com, f.kocloo@gaecgh.org (F.C.K. Ocloo). Contents lists available at ScienceDirect Radiation Physics and Chemistry journal homepage: www.elsevier.com/locate/radphyschem https://doi.org/10.1016/j.radphyschem.2022.110041 Received 21 July 2021; Received in revised form 24 January 2022; Accepted 16 February 2022