Irradiated Beef Research Articles

Effect of information and information source on consumer preference for food irradiation

The effect of consumer information about food irradiation and the source of the information was studied through a survey mailed to 400 residents each of Manhattan and Topeka, Kansas. Two-thirds of the surveys contained a brochure providing answers to frequently asked questions about irradiation, one-third did not. Half of the informational brochures were altered to suggest they were from industry, half from the government. The survey questioned consumer choice between irradiated and non-irradiated ground beef patties, with price differentials from 10 cents/lb to 40 cents/lb costlier for irradiated patties. A greater price differential resulted in less preference for irradiated beef patties. The informational brochure increased the choice of irradiated patties, with that from a “government source” rather than an “industry source” being more effective (57% compared to 51%).

Chefs’ attitudes in North‐Eastern US toward irradiated beef, Olestra, rBST and genetically engineered tomatoes

AbstractSocial and economic factors, such as cost, income, attitudes, availability and convenience have traditionally impacted consumer food choices. Newer determinants of food choice include the effects of legislation, technology and the increase in percentage of meals eaten outside the home (45% today, projected to be 53% by 2010). In this decade, controversial food technologies include irradiation, genetic engineering and and development of non‐digestible fat substitutes. With higher frequency of meals eaten outside the home, there is an increase in transfer of decision making from individuals and families to chefs. This study surveyed 115 chefs for their awareness of and willingness to purchase such technically altered foods. Chefs were also queried concerning support for labeling for genetically modified ingredients and foods. Irradiated ground beef and genetically engineered tomatoes had high levels of willingness to purchase; potato chips made with Olestra had the lowest level of willingness to purchase. Chefs supported mandatory labeling of food containing genetically modified ingredients.

Liking of Ground Beef Patties is Not Affected by Irradiation

ABSTRACT: Our objectives were to determine the acceptability of irradiated fresh ground beef and to determine whether the acceptability was affected by information about benefits or by identifying the samples. The 218 subjects were separated into 4 groups comprising a 2 × 2 design of benefits and information. All subjects tasted 4 patties: 2 irradiated and 2 control. Ratings of overall liking, toughness, and flavor and texture liking were equal for both. Subjects rated the irradiated beef patties juicier than the nonirradiated. Benefit information and sample identification increased the liking ratings of the patties‐because the group with no benefit information and no sample identification generally rated all samples lower.

The effects of herbal pre-seasoning on microbial and oxidative changes in irradiated beef steaks

Abstract This study was undertaken to examine the effects of electron beam (e− beam) irradiation, with and without pre-seasoning with ginseng and garlic herbs, on microbial growth and oxidative stability of beef sirloin steaks. All dosages (e.g. 2, 3 and 4 kGy) of e− beam irradiation were effective at reducing the population of psychrotrophic bacteria in beef steaks. A further reduction in psychrotroph count was observed with the pre-seasoning of garlic, in both non-irradiated and irradiated steaks. The use of 3 and 4 kGy irradiation dosages, however, increased lipid oxidation during 4 weeks of storage. Ginseng decreased malondialdehyde concentrations in sirloin steaks more than garlic after e− beam irradiation of meats but had no effect on psychrotroph count. Inhibition of lipid oxidation by ginseng also minimized the discolouration of surface redness on sirloin steaks. The pre-application of garlic to irradiated steaks resulted in a lower hardness value and relative moisture loss. Electron beam irradiation, after pre-seasoning with ginseng or garlic, was shown to enhance the quality of beef sirloin steaks.

Consumer Acceptance of Irradiated Meat and Poultry in the United States

Food manufacturers in the United States are currently allowed to irradiate raw meat and poultry to control microbial pathogens and began marketing irradiated beef products in mid-2000. Consumers can reduce their risk of foodborne illness by substituting irradiated meat and poultry for nonirradiated products, particularly if they are more susceptible to foodborne illness. The objective of this study was to identify the individual characteristics associated with willingness to buy irradiated meat and poultry, with a focus on five risk factors for foodborne illness: unsafe food handling and consumption behavior, young and old age, and compromised immune status. A logistic regression model of willingness to buy irradiated meat or poultry was estimated using data from the 1998–1999 FoodNet Population Survey, a single-stage random-digit dialing telephone survey conducted in seven sites covering 11% of the U.S. population. Nearly one-half (49.8%) of the 10,780 adult respondents were willing to buy irradiated meat or poultry. After adjusting for other factors, consumer acceptance of these products was associated with male gender, greater education, higher household income, food irradiation knowledge, household exposure to raw meat and poultry, consumption of animal flesh, and geographic location. However, there was no difference in consumer acceptance by any of the foodborne illness risk factors. It is unclear why persons at increased risk of foodborne illness were not more willing to buy irradiated products, which could reduce the hazards they faced from handling or undercooking raw meat or poultry contaminated by microbial pathogens.

Growth Rates of Salmonella and Escherichia coli O157:H7 in Irradiated Beef

Ground beef was irradiated to 0, 2, or 4 kGy and then inoculated with a mixed culture of four serotypes of salmonellae or five strains of Escherichia coli O157:H7. The ground beef was stored at either 15 or 25°C, and the growth of the inoculated bacteria was monitored over time. Growth parameters were determined for both the salmonellae and the E. coli O157:H7 using the Gompertz equation. There was no significant difference in lag phase duration or generation time, irrespective of the dose to which the ground beef had previously been exposed. Furthermore, the lag phase durations and generation times determined in this study did not differ significantly from previously published values. This suggests that, although irradiation eliminates a significant portion of the spoilage microflora in ground beef, the absence of this microflora provides no competitive advantage to the growth of salmonellae or E. coli O157:H7 in ground beef.

Consumer purchase behaviour of irradiated beef products: a simulated supermarket setting

AbstractIn December 1997, the US Food and Drug Administration approved the use of irradiation to kill harmful bacteria in beef. As a result of limited information about consumers’ potential response to implementation of this technology, a supermarket simulation setting (SSS) test was conducted to assess consumer purchase behaviour. The objectives were to determine consumers’ willingness to purchase irradiated beef products when provided with information at the grocery store level and consumer's perceptions towards irradiated beef. Primary household grocery shoppers (n = 207) in Griffin, Georgia, USA who consumed beef at least twice per week participated in the study. Ground beef, ground chuck, top round steak and rib eye steak were displayed in refrigerated cases in either traditionally labelled packages (non‐irradiated) or in packages labelled as irradiated. Irradiated and non‐irradiated beef had the same unit price. Participants were instructed to purchase two packages of each cut on their first shopping trip; they then shopped a second time after an informative poster about irradiation had been placed in the display cases. The results indicated that irradiation information displayed on the poster at the point of purchase was effective in causing significant change in beef purchase behaviour. The information caused some consumers who had bought traditional packages initially to buy irradiated packages subsequently while others who bought irradiated packages initially subsequently bought traditional packages. Hence, the net effect of the information was minimal. A mean test across form/cut showed that consumers did not differentiate between the ground form and the muscle form in selecting irradiated packages.

Consumer purchase behaviour of irradiated beef products: a simulated supermarket setting

Consumer purchase behaviour of irradiated beef products: a simulated supermarket setting

A comparison of γ-irradiation and microwave treatments on the lipids and microbiological pattern of beef liver

The effects of γ-irradiation (0, 2.5, 5 and, 10 kGy) and microwaves (generated from an oven at low and defrost settings for 0.5, 1 and 2 min) treatments on the chemical composition and microbiological aspects of beef liver samples were studied. The chemical and microbiological analyses were performed on the non-treated and treated beef liver immediately after treatments and during frozen storage (-18oC) for 3 months. The chemical analyses of beef liver lipids showed that acid, peroxide and TBA values were slightly increased after irradiation treatments and also during frozen storage (-18oC). On the contrary, iodine value of the treated beef liver was decreased. Irradiation treatments remarkably reduced the total bacterial counts in beef liver. The percent reduction of bacterial load for beef liver exposed to microwaves generated from an oven at defrost mode for 2 min and after 3 months at -18oC was 62%. The bacterial load for beef liver exposed to γ-irradiation at 10 kGy after 3 months at -18oC was decreased by 98%. Hence, γ-irradiation treatment was far better than microwave treatment for reduction of the associated microorganisms with beef liver. Salmonellae was not detected in non-irradiated and irradiated beef liver throughout the storage period.

EPR evaluation of absorbed doses in γ-irradiated animal bone tissues

The accumulation of CO2- radicals in γ-irradiated porcine, chicken, bovine, walleye pollack, and navaga bone tissues and chicken eggshells was studied by EPR spectroscopy for the purpose of detecting irradiated food and evaluating the dose absorbed during its radiation processing. It was found that, in the dose range 0–10 kGy, the concentration of radicals is a linear function of dose, and the variation coefficient of the radiationchemical yield of radicals is no higher than 30% for bone tissues from various biological species. The applicability of the additive dose method to the EPR dosimetry of irradiated beef was examined. A linear regression model used in the additive dose method was found to give overestimated results, as compared with an exponential fitting model.

Conformational changes of myosin by gamma irradiation

Conformational and decompositional changes of bovine skeletal muscle myosin caused by gamma irradiation were studied for understanding the effects of irradiation treatment on myofibrillar proteins. Myosin solution and beef cuts were irradiated 0, 1, 3, 5 and 10 kGy. Competitive indirect enzyme linked immunosorbent assay (Ci-ELISA) showed that subunits of myosin were structurally modified with different patterns. Binding abilities of anti-myosin whole molecule and anti heavy meromyosin S-1 IgG, which were produced from rabbits, with irradiated myosin decreased in the same tendency depending upon the dose. Anti-light meromyosin IgG appeared to have the highest binding ability at 3 kGy. Irradiated beef cuts (≥5 kGy) could be identified by Ci-ELISA. Myosin solution became increasingly turbid with increasing dose. Hydrophobicity of myosin solution also increased by irradiation. Electrophoretic patterns showed that the myosin heavy chain disappeared and new bands were generated at higher molecular weight ranges.

The effect of ionising radiation on the colour of beef, pork and lamb

The effect of irradiation (0 and 5 kGy) of beef, pork and lamb portions in retail overwrap packs and subsequent storage at 4°C was studied in relation to colour changes. The colour of the exterior surface of beef and pork was measured on the same samples on each day of storage for up to 7 days post irradiation. On day 7 the colour of a freshly cut surface was measured. The colour of both the exterior and a freshly cut surface of lamb, in similar retail overwrap packs was measured at 2, 5 and 7 days, post irradiation, different samples being used on each day of measurement. L* values of irradiated beef increased significantly with storage and a* values for unirradiated samples decreased significantly with storage. For lamb there was a general increase in L* and h o values and a decrease in a*, b* and C* values with storage. Analyses of the day 7 data showed statistically significant effects for species on all CIELAB parameters. Irradiation resulted in significantly higher hue angle ( h o) values and the a*, b* and C* values were significantly higher on the exterior than freshly cut surface. There were a number of statistically significant 2 factor and 3 factor interactions. The role of formation of a carboxyhaem pigment in the colour of irradiated meat is discussed. The problem of interpretation of pigment changes from CIELAB values is highlighted.

IRRADIATION AND STORAGE EFFECTS ON AROMA AND COLOR OF RAW BEEF PATTIES IN ANAEROBIC OR AEROBIC PACKAGING1

ABSTRACT Effects of irradiation (2 kGy) of ground beef from trimmings aged 3, 6, or 9 days postmortem (PM) and packaged aerobically or anaerobically on lean color and aroma were investigated. Irradiation increased off‐odors and reduced color scores and Hunter a* (redness) and b* (yellowness) values (P < 0.05). Aerobic packaging increased (P < 0.05) off‐odors and Hunter L* (lightness) and b* values while reducing color scores and a* values. Irradiated patties made from trimmings of the shortest aged meat, 3‐days, had higher color scores and a* values, compared to irradiated samples aged 6‐ and 9‐days PM (P < 0.05). Irradiated patties packaged aerobically had more (P < 0.05) off‐odors, hue angle and L* and b* values and lower color scores and a* values when compared to irradiated anaerobic patties. Thus, irradiated beef patties should be made of short aged trimmings and anaerobically packaged to prevent discoloration and off‐odors.

Color Characteristics of Irradiated Vacuum‐Packaged Pork, Beef, and Turkey

ABSTRACTChanges in color of irradiated meat were observed to be species‐dependent. Irradiated pork and turkey became redder due to irradiation but irradiated beef a* values decreased and yellowness increased with dose and storage time. The extent of color change was irradiation dose‐dependent and was not related to myoglobin concentration. Visual evaluation indicated pork and turkey increased in red ness whereas beef decreased in redness as dose levels increased. Reflectance spectra showed that irradiation induced an oxymyoglobin‐like pigment in pork and that both oxymyoglobin and metmyoglobin developed in beef as a result of irradiation.

SENSORY ANALYSIS OF IRRADIATED GROUND BEEF PATTIES AND WHOLE MUSCLE BEEF1

ABSTRACTThe effects of two doses (2.0 and 3.5 kGy) of nonradioactive irradiation on flavor, texture and aroma were compared to nonirradiated controls for (1) frozen raw and precooked, ground beef patties with 10 and 22% fat packaged in vacuum or aerobically; (2) frozen, vacuum‐packaged, boneless beef steaks; and (3) chilled, vacuum‐packaged, boneless, beef steaks that were repackaged in an oxygen‐permeable film (PVC) after 14 days of storage. Samples were evaluated by a highly trained descriptive panel for fifteen sensory attributes for ground beef patties and eighteen sensory attributes for whole muscle beef. Irradiation had minimal effects on flavor, texture, and aroma of frozen, raw and precooked, ground beef patties; frozen boneless beef steaks; and vacuum‐packaged, chilled, boneless, beef steaks. Reintroduction of oxygen to irradiated beef by repackaging into PVC film after vacuum aging increased liver‐like (at 3.5 kGy) and toughness (at 2.0 kGy) attributes and slightly decreased beef identity and browned/roasted flavor notes (at 2.0 kGy.)

Sensory traits, color, and shelf life of low-dose irradiated beef steaks (1996)

Irradiation had minimal effects on flavor and texture of frozen or chilled vacuum-packaged boneless beef steaks. A dose level of 3.5 kilograys (kGy) reduced beef aroma in chilled steaks. Irradiation did not influence internal or external cooked color, most raw color traits, cooking loss, pH, oxidative rancidity, or Warner-Bratzler shear force in chilled or frozen boneless steaks. PVC-wrapped controls were less red than irradiated steaks after 5 days of display. Exposure to oxygen by repackaging into oxygen-permeable film increased oxidative rancidity after display. Vacuum-packaging, in combination with irradiation, enables boneless beef steaks to be stored and/or displayed up to 28 days with minimal effects on color, oxidative rancidity, and bacterial counts.

Evaluation of a Gas Chromatographic Method to Identify Irradiated Chicken, Pork, and Beef by Detection of Volatile Hydrocarbons

A method suitable for routine application was used in an interlaboratory study to detect irradiation treatment of chicken carcass, pork, and beef. By using gas chromatographic analysis, 17 participating laboratories determined the quantity of 4 different radiation-induced volatile hydrocarbons (tetradecene, pentadecane, hexadecadiene, and heptadecene) in the fat fraction of coded specimens approximately 3 and 6 months after irradiation. The specimens of each type of meat were supplied by 2 different producers. The dose range tested (0.6-7.5 kGy) included levels commercially used to reduce the number of contaminating microorganisms (1-5 kGy). The method employed permitted a correct identification of irradiated or nonirradiated in 98.3% of the 864 specimens.

Quantitation of cholesterol oxidation products in unirradiated and irradiated meats

A method to detect 7‐ketocholesterol, cholesterol‐5β,6β‐epoxide, cholesterol‐5α,6α‐epoxide, 4‐cholesten‐3‐one, 4,6‐cholestadien‐3‐one and 4‐cholestene‐3,6‐dione in unirradiated and irradiated beef, pork and veal was developed by use of chloroform‐methanol‐water extraction, solid‐phase extraction, column separation, thin‐layer chromatography and gas chromatography. This method recovered 78–88% of the cholesterol oxidation products and detected the cholesterol oxidation products at 10 ppb or higher. Irradiation of the meats to a dose of 10 kGy increased these compounds, except 4,6‐cholestadien‐3‐one for all three types of meat, over unirradiated, and except cholesterol‐5α,6α‐epoxide and 4‐cholesten‐3‐one for the pork. All the cholesterol oxidation products in the unirradiated meats increased during storage at 0–4°C for 2 wk with some exceptions for the pork. The increases of cholesterol oxidation products in stored irradiated meats were greater than those in the unirradiated.

Alterations of mitochondrial DNA: A method for the detection of irradiated beef liver

The study of the radio degradation of DNA is one of a number of phenomena being investigated to develop methods for identifying irradiated foods. The specific behaviour under radiation of the mitochondrial DNA from beef liver gives the possibility of detecting if the product has been irradiated or not. An identification method could finally be developed. The appraisal of the mitochondrial supercoiled DNA fraction constitutes an unambiguous detection test for beef liver irradiation. A total of 120 different samples were irradiated at 5 different doses. The dose limit of detection is lower than 2 kGy. No effects due to storage conditions were observed.

Formation of gamma and delta lactones in irradiated beef.

AbstractFormation of γ and δ lactones by irradiation in beef has been recently reported. This paper provides evidence for their presence and postulates a mechanism for their formation.