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?%.     

SENSORY EVALUATION OF GROUND BEEF PATTIES IRRADIATED BY GAMMA RAYS VERSUS ELECTRON BEAM UNDER VARIOUS PACKAGING CONDITIONS

Ground beef patties were packaged in air with: nylon/polyethylene, Saran/polyester/polyethylene, or Saran film overwrap plus a styrofoam tray. Samples were irradiated at 2 kGy by either gamma rays or electron beam, and evaluated for 7 flavor, 3 mouthfeel, and 7 taste attributes by a trained sensory panel. The only difference observed between irradiated and unirradiated samples was that the latter had a more pronounced beef/brothy flavor than irradiated patties. No differences were detected according to packaging material used. Comparing the two sources of irradiation, patties irradiated by gamma rays had more intense cardboardy and soured flavors, and salty and sour tastes than patties irradiated by electron beam.     

Effects of gamma-ray,electron-beam,and X-ray irradiation on physicochemical properties of heat-induced gel prepared with salt-soluble pork protein

The objective of this study was to investigate the physicochemical and textural properties of heat-induced gels prepared with pork muscles irradiated with gamma rays, electron beams, and X-rays. Pork muscles were irradiated at 5 kGy using the different irradiation sources, and heat-induced gels were prepared from the irradiated pork muscles at a protein concentration of 5 mg/mL. Each irradiation treatment produced lower water-holding capacity, protein solubility, apparent viscosity, hardness, springiness, cohesiveness, gumminess, and chewiness than the control gel prepared with non-irradiated pork muscle (P < 0.05). In addition, gamma irradiation was more influential than electron or X-ray irradiation on the negative impacts on water-holding capacity and texture of heat-induced gels. Therefore, this study suggests that the irradiation source could be one of the significant factors affecting gelling properties of irradiated meat.     

Solid-phase micro extraction of food irradiation marker 2-dodecylcyclobutanone (2-DCB) from chicken jerky treated with glycerol

The food irradiation marker, 2-dodecylcyclobutanone (2-DCB), assayed by SPME provides a fast and simple method to estimate the irradiation history of fat-containing food products. The SPME conditions were optimized to maximize the extraction of 2-DCB from chicken jerky treats (CJT) irradiated at low (5 kGy) and high (50 kGy) doses. The extracted 2-DCB was measured using GC-MS in selected ion mode (m/z 98, and 112). Water dilution (1:5) was needed to mobilize 2-DCB and allow partition to the headspace form the CJT matrix. Increasing the incubation temperature to 80 °C resulted in higher response. Spiking control jerky samples with 2-DCB from 10 to 150 ng/g CJT compared with spiking water revealed a significant food matrix effect. This method provides a fast, simple, and environmental friendly alternative for the existing solvent extraction methods.     

Identification of 2-dodecylcyclobutanone and linear-alkanes as irradiation markers in sliced dry-cured ham

The usefulness of 2-dodecylcyclobutanone (2-DCB) and alkane hydrocarbons as irradiation markers in sliced dry-cured ham was evaluated by solid phase microextraction (SPME)-gas chromatography-mass spectrometry (GC–MS). To that aim, sliced dry-cured ham was irradiated with different irradiation doses and subsequently examined together with non-irradiated dry-cured ham used as a control sample. The SPME conditions utilized were selected as a consequence of performing an optimization process. The results found in this work reflected that the presence of 2-DCB may be used as an irradiation indicator in sliced dry-cured ham since it does not occur in non-irradiated samples. This confirms data reported in the literature on irradiated foods, other than ham. Likewise, the concentrations of alkanes C₁₄–C₁₇ increased considerably in samples irradiated with low doses, although a decrease was observed when high irradiation doses were used. As a consequence, the concentration of these compounds can also be used as an irradiation indicator when doses lower than 1.0 kGy are applied. These results are discussed.     

Survival of Pseudomonas fluorescens and Salmonella typhimurium after electron beam and gamma irradiation of refrigerated beef

The radurization effects of gamma ray and electron beam irradiation at 1.5 and 3.0 kGy on beef steaks inoculated with Salmonella Typhimurium and Pseudomonas fluorescens were investigated during 8 days of storage at 5 degrees C. Total bacterial counts and numbers of Salmonella Typhimurium and P. fluorescens were analyzed at 2-day intervals. Total bacterial counts of samples irradiated by both gamma rays and electron beam were significantly (P < 0.05) reduced by 3.8 to 5.3 log CFU/g. Salmonella Typhimurium was not detectable during the experimental period. P. fluorescens counts of beef samples irradiated by gamma rays at both 1.5 and 3.0 kGy were not detected; however, P. fluorescens in samples irradiated by electron beam at 1.5 and 3.0 kGy was recovered after 2 days, and bacterial counts reached 7.8 and 6.9 log CFU/g, respectively. Both gamma ray and electron beam irradiation reduced total bacterial counts initially, possibly extending shelf life. Irradiation was very effective in destroying Salmonella Typhimurium; however, P. fluorescens was not completely eliminated by electron beam irradiation. Consequently, gamma ray irradiation was more effective than electron beam irradiation in the destruction of P. fluorescens.     

Development and single laboratory validation for thermoluminescence detection of irradiated foods using X-ray irradiation

The thermoluminescence (TL) method using X-rays was investigated for the purpose of detection of irradiated food, and the method was validated at a single laboratory level. A small X-ray irradiator was developed as an alternative radiation source for normalization, and X-ray irradiation conditions equivalent to gamma-ray irradiation from (60)Co were established. Gamma-ray irradiated spices were used for the method validation. The detection limits (MDL) and lower limit of integrated TL intensities (MDL×10) for the spices were checked and the separation of silicate minerals from the spices was confirmed to be sufficient for TL analysis. There was no significant difference in TL glow ratio obtained using two sets of X-ray irradiation equipment including the newly developed equipment. Repeatability and intermediate precision showed no influence of analysts, X-ray irradiation equipments, or measurement days on the TL ratios. From these results, this detection method was validated in a single laboratory.     

Antioxidative activity of carnosine in gamma irradiated ground beef and beef patties

The activity of carnosine as a natural antioxidant in gamma irradiated ground beef and beef patties was studied. Samples of ground beef, in the absence and presence of 0.5% or 1.0% carnosine, as well as raw and cooked beef patties prepared with 1.5% salt (NaCl), in the absence and presence of 0.5% or 1.0% carnosine, were gamma irradiated at doses of 0, 2, and 4 kGy. The extent of oxidation in irradiated and non-irradiated samples of ground beef and raw beef patties was then determined during refrigerated (4 ± 1 °C) and frozen (−18 °C) storage, while determined for cooked beef patties during refrigerated storage only. Moreover, the determination of metmyoglobin (MetMb) accumulation and sensory evaluation for the visual color were carried out for samples of ground beef and raw patties. The results indicated that salt or salt and cooking accelerated the oxidative processes and significantly increased the peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) in the prepared non-irradiated samples. However, salt slowed down the accumulation of MetMb in raw patties. Irradiation treatments and storage in the absence of carnosine significantly (P < 0.05) increased the PV and TBARS in samples, at higher rates in salted or salted and cooked beef. Moreover, irradiation and storage significantly (P < 0.05) increased the formation of MetMb in ground beef and raw patties in the absence of carnosine. Addition of carnosine significantly (P < 0.05) reduced the oxidative processes and MetMb formation (proportionally to the used concentration) in samples post-irradiation and during storage. Furthermore, carnosine exerted significant efficacy in maintaining an acceptable visual red color post-irradiation and during storage of ground beef and raw patties. These results demonstrate that carnosine can be successfully used as a natural antioxidant to increase the oxidative stability in gamma irradiated raw and cooked meat products.     

Optimizing irradiation treatment of shell eggs using simulation

Accurate dose calculation is needed to ensure proper irradiation process control to maintain the freshness of the product. Our objective was to establish the best irradiation treatment for shell eggs taking into account their different components (shell, albumen, yolk). Computer tomography (CT) data were used to generate a 3-D geometry to simulate dose distributions within 1 egg using a radiation transport code (MCNP5). Radiation energies used for simulation were 10 MeV (high-energy) and 1.35 MeV (low-energy) for electron beam, 5 MeV for X-rays, and 1.25 MeV for a gamma-rays source such as Co-60. Low-energy (surface) e-beam simulation indicated that electrons only penetrate up to the thin albumen (0.6 cm). Because of their irregular shape, shell eggs should be irradiated from the side (rather than from top or bottom) for better dose distribution. For high-energy e-beam simulation, the entire egg was irradiated and the best results were obtained when the egg was irradiated from both sides, showing a dose uniformity ratio (D(max)/D(min)) of 1.42. X- or gamma-ray source simulation from one side only, the dose uniformity ratio was 3.38 and 3.12, respectively. For surface-only irradiation, a low-energy e-beam provides a uniform dose distribution. To irradiate the entire egg, 2-sided high-energy e-beam sources are required for an efficient treatment. Unless the product rotates in front of the source, the dose uniformity ratio for X-ray or gamma ray is not adequate for shell egg treatment for pathogen decontamination purposes. Practical Application: Proper control of irradiation treatment of foods such as shell eggs is critical to ensure pathogen inactivation while maintaining product freshness. Simulation allows for accurate calculation of dose distribution within the egg to further establish the best irradiation scheme.     

Solid phase microextraction as a methodology in the detection of irradiation markers in ground beef

The usefulness of solid phase microextraction (SPME) to detect the occurrence of the irradiation markers 2-dodecylcyclobutanone (2-DCB) and 1,3-bis(1,1-dimethylethyl)benzene in irradiated ground beef was evaluated. To that aim, beef samples were irradiated with different irradiation doses and subsequently examined together with non-irradiated beef samples used as control samples. The SPME conditions applied were selected as a result of performing an optimization process including different fibers (PDMS, DVB/CAR/PDMS, polyacrylate and PDMS/DVB), as well as extraction times (10, 25 and 40 min) and temperatures (40 and 60 °C). For comparison, 2-DCB and 1,3-bis(1,1-dimethylethyl)benzene were additionally identified in some of the samples by steam distillation–solvent extraction (SDE). Although this study is a preliminary work, from the results obtained SPME seemed to be a rapid and valuable technique to determine 2-DCB and 1,3-bis(1,1-dimethylethyl)benzene in ground beef subjected to irradiation, offering advantages over other methods reported in the literature. In addition, SPME allowed to confirm the validity of 2-DCB as an useful marker to distinguish non-irradiated from irradiated ground beef. On the contrary, the occurrence of 1,3-bis(1,1-dimethylethyl)benzene was however established in both types of samples by SPME and SDE.     

Effects of gamma irradiation dose and short-term storage on phytochemicals,antioxidants, and textural properties of boiled ‘Tainan 9’ peanuts

Boiled peanuts are preferable as a ready-to-eat healthy snack; however, gamma irradiation as a postharvest treatment of raw peanuts may induce unfavourable food components. Hence, the phytochemical, antioxidant, and the texture of boiled ‘Tainan 9’ peanuts pretreated with gamma irradiation (0, 2.5, 5, and 10 kGy) and stored at 29 ± 2 °C for up to 180 days were investigated. Both gamma irradiation and storage time contributed to testa darkening in raw peanuts. In boiled irradiated products, irradiation doses and storage time affected the moisture content (MC), total proteins, total oil, total soluble sugars, and antioxidant capacity (P ≤ 0.05). Total phenolic and flavonoid contents showed an increase at days 90 and decreased at days 180 across all treatments. A positive correlation was observed among ferric reducing antioxidant power (FRAP), total phenolics, and total flavonoids. Gamma irradiation at 10 kGy led to increase of peroxide value (PV) (P ≤ 0.05), but malondialdehyde (MDA) content was unaffected. Textural properties of boiled irradiated peanuts were soft. As a result, gamma irradiation at 5 kGy is recommended for postharvest treatment of raw peanuts with subsequent storage up to 180 days to obtain the eating quality of boiled peanuts with good phytochemicals and antioxidant properties, which is a challenge for food industry.     

Sensory Evaluation of Irradiated Ground Beef Patties for the National School Lunch Program

ABSTRACT: The 2002 Farm Bill allows irradiated ground beef to be distributed in the Natl. School Lunch Program (NSLP). Sensory properties of irradiated ground beef specified for the NSLP were evaluated. Frozen ground beef patties with 15% fat content were either not irradiated or irradiated at doses of 1.35 and 3.0 kGy. Aroma, taste, aftertaste, and texture as well as overall liking of cooked patties after 0 and 6 mo of storage were evaluated using nontrained panels. Results showed that irradiation had no significant ( P > 0.05) effect on the ratings of any of the sensory attributes either at 0 or after 6 mo of storage. Average ratings of liking of aroma, taste, aftertaste, and overall were higher at 6 mo than at 0 mo.     

Mold and Aflatoxin Reduction by Gamma Radiation of Packed Hot Peppers and Their Evolution during Storage

The effect of gamma radiation on moisture content, total mold counts, Aspergillus counts, and aflatoxins of three hot pepper hybrids (Sky Red, Maha, and Wonder King) was investigated. Whole dried peppers packed in polyethylene bags were gamma irradiated at 0 (control), 2, 4, and 6 kGy and stored at 25°C for 90 days. Gamma radiation proved to be effective in reducing total mold and Aspergillus counts in a dose-dependent relationship. Total mold counts in irradiated peppers immediately after treatments were significantly lowered compared with those in nonirradiated samples, achieving 90 and 99% reduction at 2- and 4-kGy doses, respectively. Aspergillus counts were significantly reduced, by 93 and 97%, immediately after irradiation at doses of 2 and 4 kGy, respectively. A radiation dose of 6 kGy completely eliminated the population of total molds and Aspergillus fungi. The evolution of total molds in control and irradiated samples indicated no further fungal proliferation during 3 months of storage at 25°C. Aflatoxin levels were slightly affected by radiation doses of 2 and 4 kGy and showed a nonsignificant reduction of 6% at the highest radiation dose of 6 kGy. The distinct effectiveness of gamma radiation in molds and aflatoxins can be explained by the target theory of food irradiation, which states that the likelihood of a microorganism or a molecule being inactivated by gamma rays increases as its size increases.     

Quality characteristics of pork patties irradiated and stored in different packaging and storage conditions

Patties were made from pork loin, individually vacuum- or aerobic-packaged and stored either at 4 or -40°C. Refrigerated patties were irradiated at 0, 1.5, 3.0 or 4.5 kGy absorbed dose, and frozen ones were irradiated at 0, 2.5, 5.0, or 7.5 kGy. Samples were analyzed for lipid oxidation, volatile production and odor characteristics. Refrigerated samples were analyzed at 0, 1 and 2 weeks, and frozen ones after 0, 1.5 and 3 months of storage. With vacuum packaging, the lipid oxidation (TBARS) of both refrigerated and frozen patties was not influenced by irradiation and storage time except for the patties irradiated and refrigerated at 7.5 kGy. With refrigerated storage, panelists could detect irradiation odor at day 0, but not after 1 week at 4°C. With frozen storage, however, irradiation odor was detected even after 3 months of storage. With aerobic packaging, the TBARS of refrigerated pork patties increased with storage time. The TBARS of pork patties increased as irradiation dose increased at day 0, but the effect disappeared after 1 week at 4°C. Nonirradiated patties were preferred to the irradiated ones at day 0 because of the significant irradiation odor in the irradiated ones, but the off-odor disappeared after 1 week at 4°C. With frozen storage, patties irradiated at 7.5 kGy had higher TBARS than those irradiated at lower doses. Nonirradiated patties had higher preference scores than the irradiated ones for 1.5 months in frozen storage. Sulfur-containing compounds were responsible for most of the irradiation off-odor, but these volatilized quickly during storage under aerobic conditions. Overall, vacuum packaging was better than aerobic packaging for irradiation and subsequent storage of meat because it minimized oxidative changes in patties and produced minimal amounts of volatile compounds that might be responsible for irradiation off-odor during storage.     

Use of mild irradiation doses to control pathogenic bacteria on meat trimmings for production of patties aiming at provoking minimal changes in quality attributes

The objectives of the present work were to assess the use of moderate doses of gamma irradiation (2 to 5 kGy) and to reduce the risk of pathogen presence without altering the quality attributes of bovine trimmings and of patties made of irradiated trimmings. Microbiological indicators (coliforms, Pseudomonas spp and mesophilic aerobic counts), physicochemical indicators (pH, color and tiobarbituric acid) and sensory changes were evaluated during storage. 5 kGy irradiation doses slightly increased off flavors in patties. Two pathogenic markers (Listeria monocytogenes and Escherichia coli O157:H7) were inoculated at high or low loads to trimming samples which were subsequently irradiated and lethality curves were obtained. Provided that using irradiation doses ≤ 2.5 kGy are used, reductions of 2 log CFU/g of L. monocytogenes and 5 log CFU/g of E. coli O157:H7 are expected. It seems reasonable to suppose that irradiation can be successfully employed to improve the safety of frozen trimmings when initial pathogenic bacteria burdens are not extremely high.     

About the regulation of ionizing radiation using for food treatment in the international legislation

The international and European legislation in the field of ionizing irradiation (gamma rays, electrons or X-rays) using for food treatment for improving food safety, for disinfestation of plants or plant products and improving of technological characteristics of food are discussed in this article. Obtained data can be used for foundation of Russian legislation and normative documents in the field of radiation methods using in the food industry.     

Effects of gamma irradiation and electron beam irradiation on quality,sensory, and bacterial populations in beef sausage patties

This study compared effects of gamma ray (GR) and electron beam (EB) irradiation on quality (TBARS value, hardness, color), sensory characteristics, and total bacterial populations in beef sausage patties during accelerated storage at 30 °C for 10 days. Beef sausage patties were vacuum-packaged and irradiated by GR and EB at 0, 5, 10, 15, and 20 kGy at room temperature. The results of quality evaluation showed that the effects of GR irradiation were similar (p ? 0.05) to EB irradiation on lipid oxidation, hardness, color and sensory scores of the beef sausage patties. However, GR-irradiated samples had lower (p < 0.05) 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 patties should be useful in reducing bacterial populations with no adverse effect on quality and most of sensory characteristics (color, chewiness, and taste).     

Modification of cotton fabric for textile dyeing: industrial mercerization versus gamma irradiation

The current research is intended to investigate the effect of gamma radiation on the cotton fabric and compare the dyeability of gamma irradiated fabric with that of chemically mercerized fabric using reactive dye, Reactive Violet H3R. The gray cotton fabric samples were desized and bleached, before being mercerized or irradiated, followed by dyeing with reactive dye. The cotton fabric was exposed to variable absorbed doses of 2–10 kGy. The color strength values at various levels of temperature, pH, dyeing time, and salt concentration were evaluated using optimal conditions of mercerization and gamma-ray treatment. The comparison of color strength values for the mercerized and the gamma irradiated cotton fabric showed that the irradiated fabric had high color strength at 60 °C using dye bath of pH10 in the presence of 6 g/L of exhausting agent while dyeing for 40 min. Both mercerization and irradiation increased the surface area of fibers that substantially elevated the dyeing performance and fastness properties.     

Analytical screening studies on irradiated food packaging

Foods may be irradiated in their final packaging and this process may affect the composition of the packaging and in turn affect the migration of substances into food. Headspace and liquid injection GC-MS and HPLC with time-of-flight MS have been used to identify and estimate levels of radiolytic products in irradiated finished plastic packaging materials. Fifteen retail packaging materials were studied. Investigations were carried out into the effect of different irradiation types (gamma and electron beam), irradiation doses (1, 3, 7 and 10 kGy) and dose rates (5 kGy s^–1 for electron beam and 0.4 and 1.85 kGy h^–1 for gamma) on the radiolytic products. Any differences seen in comparing the two ionising radiation types were attributed largely to the very different dose rates; for electron beam a 10 kGy dose was delivered in just 2 s whereas using gamma it took 5.4 h. Differences were also seen when comparing the same samples irradiated at different doses. Some substances were not affected by irradiation, others decreased in concentration and others were formed upon increasing doses of irradiation. These results confirm that irradiation-induced changes do occur in substances with the potential to migrate and that the safety of the finished packaging material following irradiation should be assessed.