Study shows GR irradiation scores in sensory, quality and microbial tests

By Jane Byrne

- Last updated on GMT

Related tags Irradiation Food irradiation

Gamma ray irradiation is more effective than the electron beam version in the reduction of bacterial populations in ground beef and has no adverse effect on quality and sensory characteristics such as colour, chewiness, and taste, according to Korean researchers.

And the authors’ findings, published in the journal Meat Science, ​showed that gamma ray (GR) and electron beam (EB) irradiation caused lipid oxidation in beef patties only when irradiated more than 15 kGy.

The authors claim that their results indicate the effects of GR irradiation were similar to EB irradiation on lipid oxidation, hardness, colour and sensory scores of the beef patties but that GR-irradiated samples had lower total bacterial counts than EB-irradiated samples after irradiation, and during storage regardless of irradiation dose.

“The results indicate that use of GR irradiation up to 10 kGy on beef sausage patties is a useful decontamination technique with no adverse effect on quality and most sensory characteristics,”​ concluded the researchers.

The study

The scientists said they compared the effects of GR and EB irradiation on quality indicators such and sensory characteristics and total bacterial populations in beef sausage patties during accelerated storage at 30°C for 10 days.

They explained that beef sausage patties were vacuum-packaged and irradiated by GR and EB at 0, 5, 10, 15, and 20 kGy at room temperature.

Panellists were trained in three one hour sessions, said the scienitists, in which patties that had undergone a wide variety of treatments were served to the tasting panel in order to familiarize them with a wide range of colour, chewiness, taste, off-flavour, and overall acceptance of patties.

The authors reported that after irradiation, patties were removed from pouches, reheated and then cooled before being served to panellists. Patties were served randomly to each panellist 15 minutes after the packages were opened, they continued.

The outcome of the sensory evaluation showed that chewiness and taste of GR and EB-irradiated samples were not changed from the exposure to up to 10 kGy and 15 kGy of irradiation, respectively. Off-flavour was continuously increased by irradiation, but overall acceptance was not changed by up to 5 kGy of irradiation, added the researchers.

Bacterial load

Prior to the trial, the researchers said the total aerobic bacterial populations in the cooked beef patties (untreated) were about 3.6 log CFU/g. They found that GR irradiation decreased more total bacterial populations than EB irradiation, but bacterial populations in GR-irradiated samples and EB-irradiated samples were below detection limit (2 log CFU/ g) after irradiation more than 5 kGy and 15 kGy, respectively.

The authors said that this finding was also the echoed in previous research and showed that GR irradiation is more effective than EB irradiation for the destruction of P. fluorescens​, and psychrotrophs and mesophiles in refrigerated beef.

The study, according to the article, was funded by the Nuclear Research and Development Program of the Korea Science and Engineering Foundation.

Global potential

According to a 2009 report from Global Industry Analysts, the world food irradiation market is predicted to exceed $2.3bn by 2012 with the greatest growth potential forecast to be in the Asian and Latin American markets.

However, the analysts said that controversies and narrowing consumer acceptance have limited take up of the technology and irradiation, and though approved for selected products in Europe, irradiation is not in wide use in the region.

"Market growth thrives on factors such as industry and consumer acceptance and application parameters ranging from types of foods to be irradiated to dosage levels.

“Competition from existing proven food sterilization technologies such as steam pasteurization and refrigeration, coupled with the high capital outlay required to set up an irradiation processing plant, and stiff opposition from certain quarters thwarts widespread acceptance of the food irradiation technique,” ​said the analysts.

The report showed that the US remains the single largest market for food irradiation, accounting for an estimated 32 per cent of global demand in 2008.

Source: Meat Science
Published online ahead of print
Title: Effects of gamma irradiation and electron beam irradiation on quality, sensory, and bacterial populations in beef sausage patties
Authors: J.G. Park, Y. Yoon, J.N. Park, I.J. Han, B.S. Song, J.H. Kim, W.G. Kim, H.J. Hwang, S.B. Han, J.W. Lee

Related topics Food Safety & Quality

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