Effects of Gamma Irradiation on the Shelf-Life of Dairy-like Product

Abstract

Interest in non-thermal food preservation techniques is increasing rapidly due to the carbon cost of maintaining cool chains, prevailing trends towards more natural products and several perceived health benefits that are believed to be destroyed upon heating. Irradiation is an emerging non-thermal food preservation technology with the benefits of being an end of process technology whereby food product is treated in its final packaging hence preventing post-treatment contamination.
This study was undertaken to develop a non-food product (Kemi block) analogous to dairy products and evaluate the impacts of gamma radiation in extending refrigerated storage-life. Kemi blocks were irradiated and the time taken for any viable cells to be observed at an unsatisfactory level was determined using pasteurised milk as reference at 20,000cfu/ml. Further, in order to replicate what happens in the supply chain, no micro-organisms were introduced. The experiment was a factorial design that considered the following: Composition (protein and fat content), Radiation dose (control, 1, 3, 5 and 10kGy), Pre-irradiation holding temperatures (-15 and +5°C) and Storage days (0 – 98).
Using 20,000cfu/ml as a benchmark for rejection, Kemi blocks exposed to 10kGy dose exhibited a shelf-life in excess of 100days while at exposed dose of 5,3,1kGy and control, the shelf-life was reduced to 91,56,35 and 28 days respectively validating that irradiation at higher doses extends product shelf-life.
Based on the pre-treatment temperature models, this study justifies the argument that irradiation of frozen Kemi blocks will reduce the indirect effects exerted by free radicals formed during irradiation due to their restricted mobilization in the frozen products.

Full text

Effects of Gamma Irradiation on the Shelf-Life of Dairy-like Product
Oluwakemi. B. Odueke1. Stephen. A. Chadd1. Richard. N. Baines1 and Karim. W. Farag2.
1 School of Agriculture, Food and Environment, Royal Agricultural University, Cirencester, UK
2 Department of Food Science and Agri-Food Supply Chain Management, Harper Adams University,
Newport, UK
Abstract
Interest in non-thermal food preservation techniques is increasing rapidly due to the carbon
cost of maintaining cool chains, prevailing trends towards more natural products and several
perceived health benefits that are believed to be destroyed upon heating. Irradiation is an
emerging non-thermal food preservation technology with the benefits of being an end of
process technology whereby food product is treated in its final packaging hence preventing
post-treatment contamination.
This study was undertaken to develop a non-food product (Kemi block) analogous to dairy
products and evaluate the impacts of gamma radiation in extending refrigerated storage-life.
Kemi blocks were irradiated and the time taken for any viable cells to be observed at an
unsatisfactory level was determined using pasteurised milk as reference at 20,000cfu/ml.
Further, in order to replicate what happens in the supply chain, no micro-organisms were
introduced. The experiment was a factorial design that considered the following:
Composition (protein and fat content), Radiation dose (control, 1, 3, 5 and 10kGy), Pre-
irradiation holding temperatures (-15 and +5°C) and Storage days (0 – 98).
Using 20,000cfu/ml as a benchmark for rejection, Kemi blocks exposed to 10kGy dose
exhibited a shelf-life in excess of 100days while at exposed dose of 5,3,1kGy and control, the
shelf-life was reduced to 91,56,35 and 28 days respectively validating that irradiation at
higher doses extends product shelf-life.
Based on the pre-treatment temperature models, this study justifies the argument that
irradiation of frozen Kemi blocks will reduce the indirect effects exerted by free radicals
formed during irradiation due to their restricted mobilization in the frozen products.
18th World Congress of Food Science and Technology 22nd August 2016

Oral Presentation