Irradiated Beef Research Articles

Monitoring of changes in the concentration of volatile organic compound in beef irradiated with accelerated electrons

The need to develop safe methods for radiation processing of food products to improve their quality and extend their shelf life stimulates new scientific research aimed at increasing their effectiveness. Oxidation of lipids and proteins occurred under the impact of ionizing radiation in products with a high fat and water content, such as chilled meat and fish products, leads to the formation of volatile organic compounds in the product thus giving it a specific smell and taste. During storage, biochemical processes associated with microbial enzymatic activity and auto-oxidation develop in processed refrigerated products. These processes also modify the volatile organic compounds, which affect the organoleptic properties of the product. The method of gas chromatography-mass spectrometry was used to study the behavior of volatile compounds identified in irradiated beef samples both immediately after irradiation and four days later to determine the effective dose range for the radiation processing of beef. Monitoring of the content of volatile compounds in beef samples irradiated by 1-MeV electrons within a dose range from 0.25 to 5 kGy showed that the content of certain alcohols, aldehydes, and alkanes exhibited pronounced dose- and time-dependent character. The developed mathematical model describes the dependence of the concentration of volatile compounds identified immediately after irradiation in beef samples on the irradiation dose. The model is based on the simultaneous occurrence of two competing processes: the decomposition of compounds due to their oxidation and accumulation due to oxidation of other compounds after exposure to ionizing radiation. The results obtained revealed that the effective dosage range of radiation treatment lies between 250 and 1000 Gy.

Volatile Compound Markers in Beef Irradiated with Accelerated Electrons.

This study focuses on the behavior of volatile organic compounds in beef after irradiation with 1 MeV accelerated electrons with doses ranging from 0.25 kGy to 5 kGy to find reliable dose-dependent markers that could be used for establishing an effective dose range for beef irradiation. GC/MS analysis revealed that immediately after irradiation, the chemical yield and accumulation rate of lipid oxidation-derived aldehydes was higher than that of protein oxidation-derived aldehydes. The nonlinear dose-dependent relationship of the concentration of volatile organic compounds was explained using a mathematical model based on the simultaneous occurrence of two competing processes: decomposition of volatile compounds due to direct and indirect action of accelerated electrons, and accumulation of volatile compounds due to decomposition of other compounds and biomacromolecules. A four-day monitoring of the beef samples stored at 4 °C showed that lipid oxidation-derived aldehydes, protein oxidation-derived aldehydes and alkanes as well as alcohol ethanol as an indicator of bacterial activity were dose-dependent markers of biochemical processes occurring in the irradiated beef samples during storage: oxidative processes during direct and indirect action of irradiation, oxidation due to the action of reactive oxygen species, which are always present in the product during storage, and microbial-enzymatic processes. According to the mathematical model of the change in the concentrations of lipid oxidation-derived aldehydes over time in the beef samples irradiated with different doses, it was found that doses ranging from 0.25 kGy to 1 kGy proved to be most effective for beef irradiation with accelerated electrons, since this dose range decreases the bacterial content without considerable irreversible changes in chemical composition of chilled beef during storage.

Effect of Methionine and Age of Rat on the Occurrence of Hemorrhagic Diathesis in Rats Fed a Ration Containing Irradiated Beef

There was no mortality in weanling Sprague-Dawley rats fed non-irradiated beef. A significant (P < 0.01) number of deaths occurred in the group fed the irradiated-beef ration. Methionine reduced the mortality rate linearly (P < 0.01). The prothrombin rate (reciprocal of prothrombin time × 1000) of rats fed an irradiated-beef ration was lower (P < 0.01) than that for rats fed a ration containing nonirradiated beef. The prothrombin rate increased (P < 0.01) when the ration was supplemented with methionine. Growth was depressed (P < 0.01) by dietary methionine. Some adult Sprague-Dawley rats died of internal hemorrhages when fed a ration containing nonirradiated beef, indicating adults were more susceptible than weanling rats to hemorrhagic diathesis. Feeding irradiated beef increased the mortality (P < 0.01), but it was decreased (P < 0.01) by supplemental methionine. The methionine required to prevent hemorrhagic disease in adult rats fed nonirradiated-beef diet was less (P < 0.01) than that of rats fed irradiated beef. Feeding irradiated beef decreased the prothrombin rate (P < 0.01) and supplementation with methionine increased the rate (P < 0.01). There was a linear (P < 0.01) decrease of body weight gain with increasing supplemental methionine, which was less (P < 0.05) for rats fed non-irradiated beef than for those fed irradiated-beef rations.

Application of gamma radiation in the beef texture development during accelerated aging.

This study aimed to evaluate the effects of gamma radiation (3kGy) on the quality of post-rigor beef (M. longissimus lumborum) aged for up to 21 days at different temperatures (1, 7, and 15°C). Irradiation reduced the mesophilic and lactic acid bacteria counts, which were higher in the non-irradiated samples aged at 7 and 15°C. The water retention capacity was lower in the irradiated beef, resulting in higher values of exudation and cooking losses. High aging temperatures increased the exudation loss and myofibrillar proteolysis (lower fragmentation index; FI) and reduced the total and insoluble collagen contents and the beef Warner-Bratzler square Shear Force (WBsSF). However, irradiated beef had higher FI and SF than non-irradiated ones, increasing the time required for the beef tenderizing. Gamma irradiation (3kGy) can be used to ensure the microbiological safety during short storage at high temperatures (up to 15°C) in order to accelerate the process of beef tenderizing.

Combined effect of irradiation and butylated hydroxyanisole on shelf life and quality of beef at ambient temperature

The study was aimed to evaluate the effect of gamma irradiation and butylated hydroxyanisole (BHA) on meat quality traits and safety of beef. Samples were divided into four treatment groups treated with 0.01% BHA and gamma ray having T0 (Control), T1 (3 kGy), T2 (5 kGy) and T3 (7 kGy), respectively. The analyses were conducted at 0, 3, 5 and 7 days of interval. The study was conducted in completely randomized factorial (CRD) design. Traits evaluated were color value (L*, a*, b*), pH, drip loss, cooking loss, ERV and WHC, DM, moisture, CP, fat, ash, thiobarbituric acid reactive substances (TBARS), peroxide value (POV), free fatty acid (FFA), total coliform count (TCC), total viable count (TVC) and total yeast mould count (TYMC). Color, flavor, tenderness, juiciness and overall acceptability were significantly differed (p&lt;0.01) for days of intervals. Positive and significant interaction (p&lt;0.01) between treatment and days of interval was found for color value (L*, a*, b*), drip loss, cooking loss, ERV, WHC except raw pH. There were found positive and significant interaction (p&lt;0.01) between treatment and days of interval for DM, CP, FFA and TBARS except POV. The TYMC and staphylococcus were significantly decreased (p&lt;0.05) at different treatment groups compared to control group. Salmonella non-significantly (p&gt;0.05) increased and staphylococcus significantly (p&lt;0.01) decreased with increasing irradiated doses in beef. Hence, it may be concluded that BHA treated irradiated beef had a potential effect of shelf life to maintain quality and safety aspect of beef.

Electron beam irradiation of raw ground beef patties in the Philippines: Microbial quality, sensory characteristics, and cost-analysis

Radiation technology has been known to be an effective method to improve food safety. This study aimed to determine the effects of electron beam irradiation on microbial and sensorial qualities of beef patties and to evaluate whether this technology can be used as an alternative treatment in reducing pathogenic microorganisms in semi-processed meat for a defined period of time. Beef patties were prepared and stored at −18 °C and were irradiated at 2, 4, and 6 kGy. Exposure of beef patties at 2 kGy radiation dose significantly lowered the Aerobic Plate Count, Molds and Yeast Count, and Total Coliform as compared to non-irradiated (2.80 ± 0.01 log CFU/g vs. 5.00 ± 0.02 log CFU/g; 2.00 ± 0.01 log CFU/g vs. 3.40 ± 0.04 log CFU/g; and 1.00 ± 0.01 log CFU/g vs. 2.37 ± 0.87 log CFU/g, respectively) and exposure at higher doses further reduced the microbial load until the 7th month of storage. Electron beam irradiation is effective in reducing the microbial load of frozen beef patties with a dose as low as 2 kGy up to 7 months. These results are within the acceptable limit on meat paste/pate for aerobic microorganisms (4 Log CFU/g) and total coliform (1 Log CFU/g) set by the Philippine Food and Drug Administration (FDA) and National Meat Inspection Service (NMIS). As for the sensorial qualities, irradiated beef patties were not significantly different to the non-irradiated samples. Lastly, the potential of EB-irradiation to enhance food safety while achieving an economy of scale was demonstrated in the study.

Effect of irradiation on the quality parameters of raw beef

The objective of this study was to elucidate the relationships among lipid/protein oxidation, color changes, off-taste, and off-odor in irradiated raw beef. The raw beef round eye was prepared and irradiated at 0, 1.5, 3.0, and 4.5 kGy using a linear accelerator. Significant increases in lipid oxidation and protein oxidation were found in irradiated raw beef, while significant decreases were observed in the color values (L*-, a*-, and b*-value). The degradation of nucleotides can contribute to the taste changes (increase in sourness and decrease in umami taste) in the irradiated raw beef, which was further confirmed by the electronic tongue data. The sulfur volatiles (e.g.: dimethyl disulfide) from the sulfur-containing amino acids increased significantly after irradiation, indicating these are closely related to the off-odor of irradiated beef.

Does information on food safety affect consumers' acceptance of new food technologies? The case of irradiated beef in South Korea under a new labelling system and across different information regimes

Consumer aversion to new food technologies may be partly explained by the gap between the problem that the technology solves and what consumers actually understand about the food technology. This study assesses how accepting consumers are of food irradiation when exposed to prior information about food safety‐related issues. Using a hypothetical discrete choice experiment, this study also explores consumer demand for a new food irradiation labelling system in South Korea under different information on food irradiation (positive, negative, and positive and negative). The results indicate that Korean consumers have a negative perception of irradiated foods and that they fail to link the use of food irradiation as a vehicle to solve food safety issues, even with the new version of the irradiated food label. However, providing consumers with information about food safety‐related issues alongside with the benefits implied by the use of food irradiation resulted in more general acceptance of food irradiation. Furthermore, we conclude with a discussion of the relevant implications for policymakers, academics and food industry professionals.

The effect of electron-beam irradiation on microbiological properties and sensory characteristics of sausages

The present study aimed to evaluate the survival of Salmonella typhimurium strain ATCC 14028, total bacterial populations and sensory characteristics of irradiated beef sausages. The samples were vacuum-packaged, irradiated by electron-beam, and stored in a refrigerator. Microbiological quality was promoted by irradiation dose increase. The effect of electron-beam on color, taste, odor and consistency characteristics showed no significant differences. The results indicated that using electron-beam irradiation at 2 kGy dose was a promising method in reducing bacterial populations, eliminating Salmonella typhimurium along with acceptability of sensory characteristics.

Effect of irradiation on the parameters that influence quality characteristics of raw beef round eye

Abstract The objective of this study was to elucidate the relationships among lipid/protein oxidation, color changes, off-taste and off-odor in irradiated raw beef round eye. Raw beef round eye was prepared and irradiated at 0, 1.5, 3.0 and 4.5 kGy using a linear accelerator. Significant increases in lipid oxidation and protein oxidation were found in irradiated raw beef round eye, while significant decreases were observed in the color values (L*-, a*-, and b*-value). The degradation of nucleotides can contribute to the taste changes (increase in sourness and decrease in umami taste) in the irradiated raw beef round eye, which was further confirmed by the electronic tongue data. The sulfur volatiles (e.g.: dimethyl disulfide) from the sulfur-containing amino acids increased significantly after irradiation, indicating these are closely related to the off-odor of irradiated beef round eye.

Effects of irradiation source and dose level on quality characteristics of processed meat products

The effect of irradiation source (gamma-ray, electron-beam, and X-ray) and dose levels on the physicochemical, organoleptic and microbial properties of cooked beef patties and pork sausages was studied, during 10 days of storage at 30±1°C. The processed meat products were irradiated at 0, 2.5, 5, 7.5, and 10kGy by three different irradiation sources. The pH of cooked beef patties and pork sausages was unaffected by irradiation sources or their doses. The redness of beef patties linearly decreased with increasing dose level (P<0.05), obviously by e-beam irradiation compared to gamma-ray and X-ray (P<0.05). The redness of pork sausages was increased by gamma-ray irradiation, whereas it decreased by e-beam irradiation depending on absorbed dose level. No significant changes in overall acceptability were observed for pork sausages regardless of irradiation source (P>0.05), while gamma-ray irradiated beef patties showed significantly decreased overall acceptability in a dose-dependent manner (P<0.05). Lipid oxidation of samples was accelerated by irradiation depending on irradiation sources and dose levels during storage at 30°C. E-beam reduced total aerobic bacteria of beef patties more effectively, while gamma-ray considerably decreased microbes in pork sausages as irradiation dose increased. The results of this study indicate that quality attributes of meat products, in particular color, lipid oxidation, and microbial properties are significantly influenced by the irradiation sources.

Application of Electron-Beam Irradiation Combined with Aging for Improvement of Microbiological and Physicochemical Quality of Beef Loin.

The combined effects of irradiation and aging temperature on the microbial and chemical quality of beef loin were investigated. The samples were vacuum-packaged, irradiated at 0 or 2 kGy using electron-beam (EB), and stored for 10 d at different aging temperatures (2, 14, or 25℃). The microbial growth, shear values, meat color, and nucleotide-related flavor compounds of the samples were analyzed. The irradiation effect on inactivation of foodborne pathogens was also investigated. The population of Listeria monocytogenes and Escherhia coli O157:H7 inoculated in beef samples decreased in proportion to the irradiation dose. Irradiation reduced the total aerobic bacteria (TAB) over the storage, but higher aging temperature increased the TBA. Thus TAB increased sharply in non-irradiated and high temperature-aged (14, 25℃) beef samples after 5 d. With increasing aging temperature and aging time, shear force values decreased. Lipid oxidation could be reduced by short aging time at low aging temperature. The color a* values of the irradiated beef were lower than those of the non-irradiated throughout the aging period. As aging period and temperature increased, IMP decreased and hypoxanthine increased. Considering microbial and physicochemical properties, irradiation can be used for raw beef to be aged at relatively high temperature to shorten aging time and cost.

Combined Effect of Irradiation and Ageing Condition on Physicochemical and Microbial Quality of Hanwoo Eye of Round.

The combined effects of electron-beam irradiation and ageing of beef were examined. The irradiated samples at dose of 0 or 2 kGy were kept and analyzed for the microbial growth, shear values, meat color, and nucleotide-related flavor compounds at different ageing temperatures (2, 10, or 25℃) for 8 d. The irradiation effect on inactivation of foodborne pathogens was also investigated. The population of Listeria monocytogenes and E. coli O157:H7 inoculated in beef samples decreased in proportion to the irradiation dose, showing D10 values of 0.66 and 0.65 kGy respectively. The irradiated beef eye of round had lower number of total aerobic bacteria (TAB) than non-irradiated one during the storage, but the TAB increased with higher ageing temperature (p<0.05). Especially, TAB increased sharply in non-irradiated samples aged at 25℃ after 4 d (p<0.05). With increasing ageing temperature and ageing time, shear force values decreased (p<0.05). The color a* values of the irradiated beef were lower than those of the non-irradiated throughout the ageing period (p<0.05). As ageing time and temperature increased, the amounts of inosine monophosphate decreased and the hypoxanthine increased (p<0.05). Relatively high ageing temperature could be used at irradiated beef eye of round to shorten the ageing time.

Development of a novel biosensor based on F0F1-ATPase for the detection of 2-dodecylcyclobutanone in irradiated beef

A novel biosensor regulated by the rotator of F0F1-ATPase was developed to analyze 2-dodecylcyclobutanone (2-DCB) to detect γ-ray irradiated beef rapidly. The biosensor was assembled by conjugating 2-DCB monoclonal antibodies with the “rotator” ε-subunit of F0F1-ATPase within chromatophores through an ε-subunit monoclonal antibody–biotin–avidin–biotin linker. The limit of detection (LOD) of 2-DCB was approximately 10−8μg/mL. The recovery ratio of 2-DCB from ground beef patties ranged from 75.1% to 116.4%. The intra-assay and inter-assay coefficients of variation were both <15.0%. The proposed method was validated by gas chromatography–mass spectrometry with high correlation. The biosensor was used to detect 2-DCB in ground beef patties with different fat contents (10%, 20%, and 30%) irradiated at 0.5, 1.0, 3.0, 5.0, and 7.0kGy. The 2-DCB concentration linearly increased with the radiation dose in all the beef samples. 2-DCB concentration increased with fat levels in the three samples.

Metabolic profiling by 1H NMR of ground beef irradiated at different irradiation doses

This work describes a metabolic profiling study of non-irradiated and irradiated beef (at 2.5, 4.5 and 8kGy) using 1H NMR and chemometrics. The assignment of all major NMR signals of the aqueous/methanolic extracts was performed. A comprehensive multivariate data analysis proved the ability to distinguish between the irradiated and non-irradiated beef. Classification trees revealed that three metabolites (glycerol, lactic acid esters and tyramine or a p-substituted phenolic compound) are important biomarkers for classification of the irradiated and non-irradiated beef samples. Overall, the achieved metabolomic results show that the changes in the metabolic profile of meat provide a valuable insight to be used in detecting irradiated beef. The use of the NMR-based approach simplifies sample preparation and decrease the time required for analysis, compared to available official analytical procedures.

Effects of soy sauce and packaging method on volatile compounds and lipid oxidation of cooked irradiated beef patties

The objective of this study is to determine the effect of soy sauce on volatile compounds and lipid oxidation of cooked irradiated beef patties. Sulfur-containing volatile components, which are produced by irradiation, were not found in all treatments. Volatile components derived from soy sauce, such as 3-hydroxy-2-butanone, acetic acid, 3-methyl-1-butanol and 2-methyl-1-butanol, were detected in beef patties containing soy sauce regardless of irradiation and packaging method. Volatile aldehydes, including hexanal, significantly decreased the irradiated beef patty prepared with soy sauce compared to those of irradiated beef patty made with NaCl at 1 day and 5 days after irradiation. In addition, combined use of vacuum packaging and soy sauce treatments could inhibit the formation of volatile compounds and 2-thiobarbituric acid reactive substances during chilled storage. Therefore, the use of soy sauce in cooked and irradiated beef could reduce the production of volatile components associated with the irradiation-induced off-flavor and lipid oxidation.

Detection of Hydrocarbons Induced by Gamma and Electron Beam Irradiation in Ground Beef by Gas Chromatography–Mass Spectrometry

This study determined hydrocarbons induced by gamma and electron beam irradiation of ground beef. The samples were irradiated with 0, 2.5, 5, 7.5, 10, 15, and 20 kGy dosages of gamma-rays and an electron beam. The lipid contents were extracted by hexane and the induced hydrocarbons were separated and identified by gas chromatography–mass spectrometry. The analytical method was validated by characterization of detection limits, linearity, precision, and recovery; satisfactory results were obtained in all cases. The major hydrocarbons detected in irradiated ground beef samples were pentadecane and 1-tetradecene from palmitic acid, heptadecane, and 1-hexadecene from stearic acid, and 8-heptadecene and 1,7-hexadecadiene from oleic acid. The induced hydrocarbons were detected at irradiation levels above 2.5 kGy but not in the absence of irradiation. The induced hydrocarbons showed an increase with radiation dosage, but the concentration was slightly higher for gamma rays than for the electron beam. The 1-tetradecene, 8-heptadecene, and 1,7-hexadecadiene were detected as the major hydrocarbons and showed good linearity with irradiation level. It was concluded that these major hydrocarbons are suitable markers to distinguish irradiated and unirradiated ground beef.

Development of a Competitive Indirect Enzyme-Linked Immunosorbent Assay Based on Monoclonal Antibodies for the Detection of 2-Dodecylcyclobutanone in Irradiated Beef

A highly sensitive and specific competitive indirect enzyme-linked immunosorbent assay (ciELISA) based on monoclonal antibodies was developed for the detection of 2-dodecylcyclobutanone (2-DCB), a chemical marker for irradiated lipid-containing foods. 2-Oxocyclobutane undecanoic acid was used as an alternative to 2-DCB and conjugated to BSA and OVA via a conventional carbodiimide condensation reaction to prepare the immunogen and the coating antigen for 2-DCB. The monoclonal antibody against 2-DCB was obtained using the hybridoma technique, with a high specificity and low cross-reactivity for 2-tetradecylcyclobutanone (2-TCB; <8%) and other structurally related compounds (<0.1%). The ciELISA method was applicable at optimal experimental conditions of 0.001-100 μg/mL 2-DCB in a buffer solution, with an IC50 value of 0.25 μg/mL and a limit of detection (defined as the IC20) of approximately 0.004 μg/mL. The recovery efficiency of 2-DCB from ground beef patties ranged from 84.4 to 109.8%. The intra-assay and interassay coefficients of variation were <10.0 and <12.0%, respectively. The proposed method was validated by gas chromatography-mass spectrometry with high correlation. The same method was used to detect 2-DCB in ground beef patties irradiated at 0.5, 1.0, 3.0, 5.0, and 7.0 kGy; the 2-DCB concentration linearly increased with the radiation dose.

Determination of Optimal Storage Condition for Pre-packed Hanwoo Loin

The aim of this study was to determine the optimal storage condition of pre-packed Hanwoo beef without freezing. Hanwoo loin was purchased from a local distributor at 48 h after slaughter, then sliced in 1.5±0.5 cm thickness, and packed in a polyethylene (PE) tray covered with linear low-density polyethylene (LLDPE) film. The studied factors to set the optimal storage condition were chamber temperature (5, 2.5 and -1 o C for 14 d), cooling method (direct and indirect cooling system), and ultraviolet (UV) light irradiation for beef surface sterilization (0, 30, 60, and 120 min). The changes of pH, thiobarbituric acid reactive substances (TBARS) and number of aerobic bacteria were measured during storage. Beef samples stored in -1 o C showed the minimal increasing rate in TBARS and microbial growth. After 15 d of storage, there was no significant difference in pH and TBARS values. However, the microbial population of beef stored in direct type cooling chamber (4.25±0.66 Log CFU/g) was significantly lower than that of beef stored in indirect type chamber (6.47±0.08 Log CFU/g) (p<0.05). After 4 d of storage, 60 or 120 min UV light irradiated beef samples showed significantly lower microbial population, and at 14 d of storage, 60 min UV irradiated beef sample showed significantly lower microbial population (3.14±0.43 Log CFU/g) than control (4.46±0.13 Log CFU/g) (p<0.05). However, TBARS values of 60 or 120 min UV light irradiated beef samples were significantly higher than non-irradiated beef sample after 4 d of storage (p<0.05).

2-Dodecylcyclobutanone as an irradiation dose indicator to identify and estimate original dose in irradiated ground beef

2-Dodecylcyclobutanone (2-DCB), as a chemical marker of irradiated lipid-containing foods, was used to detect whether ground beef patties were irradiated and to estimate the original absorbed dose. The ground beef patties (70/30) were irradiated at five targeted absorbed doses of 0.5, 1.0, 3.0, 5.0, and 7.0 kGy and stored for 0, 7, 14, 21, and 28 days, respectively at 4 °C. A rapid analytical method based on direct solvent extraction (DSE)/gas chromatography–mass spectrometry (GC–MS) was developed to analyze 2-DCB in γ-ray irradiated ground beef patties. The samples were extracted with acetonitrile via DSE using a tissue-mashing instrument, and then purified with a 1-g silica cartridge and analyzed via GC–MS. The results indicate a linear relationship between irradiation dose and the amount of 2-DCB produced in the irradiated samples (y = 0.0608x–0.0004, R² = 0.9899). In addition, a linear relationship was observed between the loss (%) of 2-DCB and storage time (L = 1.958d–1.6596, R² = 0.9597). Thus, a method for estimating the initial dose of irradiated food was developed based on these two line equations; this method explored the establishment of a determination model of the original irradiation dose of lipid-containing foods. The method was used to successfully estimate 2–7 kGy irradiated beef samples within 28 days with minimal deviation within ±15 %.