Electron beam processing of fresh and/or frozen raw ground beef

H.E. Clemmons , ... E.J. Brown , in Electron Beam Pasteurization and Complementary Food Processing Technologies, 2015

14.5 Product feasibility testing

Ground beef may be electron beam irradiated in various product and packaging configurations. The configurations must adhere to the dimensional requirements that permit proper and uniform dose delivery. The precise dimensional requirements for uniform dose delivery are determined through the feasibility testing. Feasibility testing allows the manufacturer to design the ideal product configuration, packaging, and master case layout. Each of these identified parameters for each of the ground beef products to be irradiated will allow for the proper penetration and uniform electron distribution and dose delivery.

Height or thickness of the ground beef in relation to how the electron beam is presented to the surface of the ground beef is the primary dimensional requirement that determines a uniform dose delivery. The "height" of the ground beef is the ground beef's overall height excluding packaging material and airspace. The height of the ground beef affects the electron distribution. The bulk density, beam penetration, and electron distribution in the ground beef remain constant, whether in the fresh or frozen state. Typically, the overall height is between 3.5 and 3.7 inches, which allows for a uniform electron dose distribution using a dual electron beam irradiation system. Certain factors will affect the overall height at which ground beef can be properly irradiated. Chubs, or the cylindrical tubes of ground beef, and ground beef patties, which are scored to permit quicker uniform cooking of the patty, are a couple of examples that will affect dose distributions.

When ground beef height increases and the thickness exceeds the limit for uniform deposition of electrons, the max:min ratio increases. The max:min ratio will identify the maximum thickness at which the ground beef can receive a uniform dose delivery and be properly irradiated. Eventually, as ground beef thickness increases, it will exceed the allowable thickness limit. When the allowable thickness limit is exceeded, the beam will not penetrate to the center of the ground beef, resulting in a minimal dose of electrons being distributed to the center of the ground beef (Fig. 14.1).

Figure 14.1. Dual beam max:min ratio dose uniformity unacceptable: ground beef thickness/height is too tall or thick (low or no dose is in the center of the product).

When ground beef thickness is lessened or thinned, the beam penetration and electron distribution will overlap. The overlap of the electrons results in an increased dose in the center of the ground beef and the max:min ratio increases. The max:min ratio will identify the minimum thickness at which the ground beef can receive a uniform dose delivery and be properly irradiated. Eventually, as thickness decreases, it will allow additional packages of ground beef to be stacked until the thickness achieves a thickness for uniform dose delivery and a reasonable max:min ratio. When the allowable thickness limit is too thin or minimized, the electrons will abundantly penetrate to the center of the ground beef resulting in a higher than desired dose being delivered to the center of the product (Fig. 14.2).

Figure 14.2. Dual beam max:min ratio dose uniformity unacceptable: ground beef thickness/ height is too thin or short (high dose is in the center of the product).

Determining if the total overall height of the ground beef must be increased or decreased is dependent on the dose point measurement within the ground beef that receives the least or minimum dose during the irradiation treatment. When the minimum dose point is in the center of the ground beef and maximum dose point is near to or on the surface of the ground beef, the product's height must be decreased. When the minimum dose point is near or on the surface of the ground beef and the maximum dose point is in the center the product's height must be increased.

The ideal height or thickness is established when the irradiation dose is uniformly distributed throughout the ground beef. The optimal product height or thickness for irradiation is identified when the measured absorbed dose applied to the top and bottom surfaces and the midpoint at the center of the ground beef are all equal (Fig. 14.3).

Figure 14.3. Dual beam max:min ratio dose uniformity acceptable: ground beef thickness/height is ideal (dose is uniformly distributed and will be properly applied throughout the product).

Ground beef with overall thickness too thin for uniform dose delivery but is too thick when the packages are double stacked for uniform dose delivery, can be irradiated using attenuation. Attenuation is the use of an absorption fixture placed between the ground beef and linear accelerator applying the electron beam, to absorb a specified amount of electrons being applied to the product.

The thickness of the attenuation required to adsorb the electrons for uniform dose delivery in ground beef that is packaged too thin is a product of the density of the attenuation fixture material used, the density of the ground beef, and its overall thickness. Attenuation acts as a replacement or a filler for the ground beef to get to the required density needed to achieve a uniform dose delivery and tight max:min ratio.

While the use of attenuation is an alternative to achieving uniform dose delivery, its use will reduce the irradiation processing efficiency. eBeam irradiation efficiency is reduced as a result of the electrons being deposited in the attenuation device instead of being delivered into the ground beef to reduce foodborne pathogens and adulterants. Consideration should be given in identifying and designing the height of the ground beef and packaging configuration to achieve a uniform dose delivery.

Feasibility testing will also assist the manufacturer in the development, engineering, and designing of each individual stack of ground beef patties, individual package of ground beef, and master case layout of stacks of beef patties or individual packages. Individual package and master case design is the second most critical step in the engineering and feasibility testing process.

The purpose of identifying the ideal thickness of each ground beef product is to achieve a uniform dose delivery throughout the product with a fairly tight targeted max:min ratio. The targeted max:min ratio range for the best ground beef organoleptic values and ground beef performance is typically 1.35–1.45   max:min when ground beef is packaged at the ideal height or thickness.

While it is important to maintain a tight max:min ratio for both quality attributes and processing efficiencies, the manufacturer may determine during the feasibility testing phase whether some other max:min ratio is suitable for irradiating the ground beef. The max:min ratio is based on the manufacturer's desired end results for ground beef's safety and acceptability. The manufacturer's criteria for the ground beef include the evaluation and results for reduction of foodborne pathogens and adulterants, organoleptic properties and product performance. The ground beef's max:min ratio is driven by the height or thickness of the ground beef to be irradiated. Identifying the proper height or thickness will yield the tightest or best max:min ratio for irradiating the ground beef. The irradiation dose uniformity delivered throughout the ground beef is measured and calculated by dosimetry.

Dosimeters are used to measure the dose of ionizing radiation to which the ground beef has been exposed. There are two types of dosimeters: alanine in the form of pellets or films, and radiochromic dye films. Alanine pellets and alanine films are considered the "Gold Standard" in dosimetry. They are placed at identified measurement points throughout the ground beef. The measurement points identify where the ground beef receives the lowest minimum dose and highest maximum dose of irradiation. Dividing the maximum dose by the minimum dose equates to the max:min ratio. If the calculated ratio allows the ground beef to be irradiated within the customer's established minimum to maximum dose range, then product configuration is established. If the calculated ratio does not allow the ground beef to be irradiated within the customer's established minimum to maximum dose range, additional product engineering is required.

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Fresh and cured meat processing and preservation

Steven M. Lonergan , ... Dennis N. Marple , in The Science of Animal Growth and Meat Technology (Second Edition), 2019

Ground Beef

Ground beef is a major market for beef in the United States. More than one half of the beef sold in the United States is in the form of ground beef. It has a big market share in fast-food restaurants, traditional restaurants, institutions, and in US homes. The terms ground beef and chopped beef are considered to have the same meaning. Ground beef is prepared by the use of mechanical, high-speed grinding and/or chopping of boneless beef cuts and trimmings. The manufacture of ground beef products is regulated by the United States Department of Agriculture—Food Safety and Inspection Service (USDA-FSIS) codes in which composition and labeling regulations of ground beef products are spelled out in detail. These regulations specify that ground beef must be made from fresh and/or frozen beef, with or without seasoning, and without the addition of fat, and is limited to 30% fat. Many ground beef products are much leaner (e.g., 90% lean, 10% fat, and they must be labeled as such). Furthermore, the regulations state that ground beef may not contain added water, extenders, or binders and not exceed 25% cheek meat (the masseter muscles of the head). Ground beef made from the round or ground beef made from the chuck must be listed on the package label to denote the cut or part used for making that specific product. Hamburger is a popular term used for ground beef, and the USDA definition for hamburger is only slightly different from that for ground beef. Based on its legal definition, hamburger can have added beef fat. Interestingly, hamburger has nothing to do with the pork carcass wholesale cut, ham.

A product labeled "beef patties" is different from ground beef in that beef patties can contain binders and extenders and may or may not have added water. The word patty is commonly used to describe ground beef products. Low-fat beef patties are those products combining meat and other nonmeat ingredients for the production of low-fat meat products. These products must be labeled as low fat, fat reduced, and/or containing nonmeat ingredients. In addition to being used in patties, it is also used in the manufacture of foods such as pizza, spaghetti, tacos, and burritos, and often it is frozen for use in ready to heat and serve dishes such as casseroles. A large amount of patty manufacturing takes place by using a continuous system of grinding, blending, forming, freezing, and packaging. Large beef-patty processing plants have equipment capable of producing 10,000 pounds per hour. Fat content is monitored online by rapid analytical methods like infrared (Fig. 13.1). Immediate and constant analysis is essential in producing the desired blends of lean and fat to meet company specifications and making necessary blend adjustments. Special meat grinder plates are available to greatly reduce or eliminate any bone particles that have been part of the beef trimmings (Fig. 13.2). Use of rapid cryogenic freezing substances such as liquid nitrogen (−   80°F) has become more common because of its beneficial effects on decreasing cooking loss and improving the flavor of the ground beef products. After rapid freezing, the packaged ground beef product is placed in freezers for storage for subsequent shipment to retail stores, restaurants, and institutions.

Fig. 13.1

Fig. 13.1. An example of a rapid analytical method to determine the fat, moisture, and protein percentages of ground beef using an infrared unit.

 From: NDC Infrared Engineering Inc., Irwindale, California.

Fig. 13.2

Fig. 13.2. Special meat grinder plates used to greatly reduce or eliminate bone particles in ground beef products.

 Courtesy, Iowa State University Meat Science Laboratory.

Precooking patties at the wholesale level is becoming increasingly more popular because of the demand for rapid meal preparation and service, especially in the fast-food industry. Usually, the three stages of precooking doneness are fully cooked, partially cooked, and char-marked. Also, ground lamb, pork, chicken, and turkey patties are manufactured for retail sale using the same techniques described for beef patties.

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Handling of hamburgers and cooking practices

Daniel A. Unruh , ... Sara E. Gragg , in Food Hygiene and Toxicology in Ready-to-Eat Foods, 2016

Storage

Upon purchase, ground beef should be refrigerated or frozen as soon as possible. This practice both preserves freshness and, importantly, slows the growth of any bacteria present in the beef. Fresh ground beef can be stored for 1–3 days at a temperature below 40°F (4.4°C), with an optimum temperature of 28°F (−2.2°C). If vacuum packaged, fresh ground beef can be stored under these conditions for up to 14 days, depending on the supplier. Frozen ground beef should be stored at, or below, 0°F (−17.8°C) for up to 90 days ( Anonymous, 2014). If properly held under these conditions, frozen ground beef is considered safe indefinitely; however, the quality will degrade throughout storage (USDA-FSIS, 2013a). Following cooking, ground beef can be refrigerated for 2–3 days below 40°F (4.4°C) and frozen up to 90 days at 0°F (−17.8°C) or below (Anonymous, 2014). If the ground beef is to be used soon, it is appropriate to refrigerate or freeze it in the original packaging. If the product will be stored in the freezer for extended periods of time it should be wrapped in aluminum foil, heavy-duty plastic wrap, freezer paper, or plastic freezer bags prior to freezing (USDA-FSIS, 2013a).

Frozen ground beef can be thawed safely in the refrigerator and should be cooked or refrozen within 1–2 days (Anonymous, 2014; USDA-FSIS, 2013a). It is also appropriate to use a microwave oven to defrost frozen ground beef; however, the ground beef should be cooked immediately, as portions of the product may have begun to cook while defrosting. Submerging frozen ground beef in cold water can also be a safe defrosting method, if the meat is placed in a waterproof plastic bag and the water is replaced every 30   min. Ground beef thawed in this manner should be cooked immediately. Ground beef defrosted in the microwave oven or submerged in cold water should never be refrozen, unless it has been cooked prior to freezing (USDA-FSIS, 2013a).

Following storage and thawing guidelines is important for ensuring quality as well as safety of ground beef products. Both spoilage and pathogenic microorganisms may be present in ground beef and can rapidly multiply between 40°F and 140°F (4.4°C and 60°C), which is known as the temperature "danger zone." Growth of spoilage microorganisms can degrade product quality, while pathogenic microbial growth poses a risk of foodborne illness (USDA-FSIS, 2013a). Before cooking, consumers may notice ground beef packaging containing a blood-like liquid remaining after taking the meat out. This liquid is known as "purge" and is a result of cellular breakage and moisture loss from the ground beef. It is completely normal and often becomes more pronounced as temperature increases or the longer the product sits in the package (USDA-FSIS, 2011).

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CANDIDA | Yarrowia lipolytica (Candida lipolytica)

J.B. Sutherland , ... S.A. CrowJr., in Encyclopedia of Food Microbiology (Second Edition), 2014

Isolation from Meat Products

Poultry, ground beef, ground lamb, sausage and other dry-cured meat products, crabs, mussels, and several types of fish frequently contain Y. lipolytica (Table 1). Even meat products in cold storage may harbor slow-growing cultures of Y. lipolytica.

Table 1. Foods that frequently contain Y. lipolytica

Beef (ground)
Butter
Cheese
Chicken
Crab
Cream
Fermented milk products (amasi, kumis, etc.)
Ham
Kefir (or kefyr)
Lamb (ground)
Margarine
Milk (cow, ewe, goat, and mare)
Mussels
Sausage
Seafood
Turkey
Yogurt

In refrigerated chickens and turkeys, 39% of the yeast isolates consist of strains of Y. lipolytica that are able to grow at 5 °C. Comparable numbers can be found in fresh, frozen, smoked, and roasted chickens and turkeys.

In dry-cured ham and sausages, Y. lipolytica is typically abundant. Although cultures may be obtained from raw ham, high numbers found in cured ham often are associated with spoilage. Yarrowia lipolytica tolerates the sulfur dioxide that often is added to unfermented sausages and also is found in many types of fermented sausage. Yarrowia lipolytica sometimes is combined with the yeast Debaryomyces hansenii and the lactic acid bacterium Lactobacillus plantarum in starter cultures for pork sausages because its lipases produce free fatty acids and other volatile compounds that add flavor to the product. It also has proteases that cause an increase in low-molecular weight peptides. In some but not all countries, the polyene antibiotic natamycin (pimaricin) is permitted to be used on sausages as a surface preservative, where it acts as an inhibitor of Y. lipolytica.

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MEAT | Eating Quality

I. Lebert , ... R. Talon , in Encyclopedia of Food Sciences and Nutrition (Second Edition), 2003

Other pathogenic bacteria causing sporadic cases

Undercooked or raw ground beef has been implicated in nearly all documented outbreaks of E. coli O157:H7 and in other sporadic cases. E. coli is a normal inhabitant of the intestine of all animals, including humans. Currently, there are four recognized classes of enterovirulent E. coli that cause gastroenteritis in humans. The enterohemorrhagic strain, designated E. coli serotype O157:H7, is a rare variety of E. coli that produces large quantities of one or two toxins that cause severe damage to the lining of the intestine. These toxins are closely related to the toxin produced by Shigella dysenteriae.

C. jejuni frequently contaminates raw chicken. Surveys show that 20–100% of retail chickens are contaminated. This is not entirely surprising, since many healthy chickens have these bacteria in their intestinal tracts. Raw milk is also a source of infections. The bacteria are often carried by healthy cattle and by flies on farms. However, properly cooking chicken or pasteurizing milk kills the bacteria. Campylobacters can be isolated from freshly slaughtered red-meat carcasses, but in smaller numbers than on poultry. This bacterium is recognized as an important enteric pathogen. Recent surveys have shown that C. jejuni is the leading cause of bacterial diarrhea in the USA, causing more illness than Shigella spp. and Salmonella spp. combined.

L. monocytogenes has been associated with foods such as raw milk, cheeses (particularly soft-ripened varieties), raw vegetables, but also fermented raw-meat sausages, raw and cooked poultry, all types of raw meats, and raw and smoked fish. Its ability to grow at temperatures as low as 3   °C permits multiplication in refrigerated foods. The contamination of meat and meat products can be due to fecal contamination during slaughter, presence on clean and unclean sections in slaughterhouses, and contaminated ground and processed meats: 10–80% of contaminated samples contain less than 10–100   CFU   g−1. L. monocytogenes is a ubiquitous bacteria found in soil, silage, and other environmental sources, and is present in the intestines of 1–10% of humans. L. monocytogenes is quite hardy and resists the deleterious effects of freezing, drying, and heat.

Y. enterocolitica has been recovered from a wide variety of animals, foods, and water. Pigs seem to be the principal reservoir of bioserotypes pathogenic to humans, but the exact cause of the food contamination is unknown.

Aeromonas spp. are ubiquitous and are also associated with foods of animal origin (raw meats, poultry, and milk). A. hydrophila grows rapidly in a refrigerated environment and can increase its number 10–1000-fold in meat and fish samples over 1 week of refrigerated storage.

Among several environments (Table 4), the home is where the pathogens are frequently identified (13%), with 46% of the outbreaks occurring in people eating at home largely due to mishandling of food products (Table 4). The consumer must take care when handling food at home, and recommendations have been given by The National Advisory Committee on Microbiological Criteria for Foods to prevent the contamination of food products by foodborne pathogens (Table 5).

Table 4. Results of foodborne disease surveillance

Place of contamination or mishandling Identified outbreaks when people eat food products Factors contributing to outbreaks
Entering the food chain at the farm (50%) Homes (46%) Temperature abuse, inadequate cooling, and improper cooking (44%)
Restaurants/hotels (15%)
Mishandling Catered events (8%) Contaminated or toxic raw products (16%)
  Restaurants (22%) Medical-care facilities (6%) Contamination by personnel or equipment (15%)
  Homes (13%) Canteens (6%) Lack of hygiene in processing, preparing, and handling (10%)
  Catering establishments (7%) Schools (5%) Cross-contamination (4%)

Table 5. Recommendations of safe food preparation

Wash hands and utensils before handling food, especially after handling raw foods
Reheat all foods thoroughly (above an internal temperature of 74   °C)
Keep hot food hot (above 63   °C)
Keep cold foods cold (below 4   °C)
Thoroughly cook meat, poultry, and seafood, and adequately heat frozen or refrigerated foods
Chill foods rapidly in shallow containers
Keep raw and cooked foods separate, especially when shopping, preparing, cooking, and storing these products
Wrap and cover foods in the refrigerator
Keep the refrigerator temperature between 1 and 4   °C

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On-line monitoring of meat quality

H.J. Swatland , in Meat Processing, 2002

10.8.2 In meat processing

Connective tissue levels in ground beef may be a problem if too many meat scraps with a high content of tendon are worked into a product. The result may be a gritty texture for hamburger, or excessive gelatin formation in a cooked product. Elastin derived from elastic ligaments has virtually the same fluorescence emission spectrum as Type I collagen from tendon and ligaments. This enables fluorescence emission ratios to be used to predict total connective tissue levels.

Under experimental conditions, collagen fluorescence in comminuted mixtures of chicken skin and muscle may be measured through a quartz-glass rod with a window onto the product (Swatland and Barbut, 1991). High proportions of skin decrease the gel strength of the cooked product (r =– 0.99), causing high cooking losses (r = 0.99) and decreased WHC (r =– 0.92). Fluorescence intensity may be strongly correlated with skin content (r > 0.99 from 460 to 510 nm) and, thus, may be strongly correlated with gel strength, cooking losses and fluid-holding capacity (Fig. 10.5). Correlations would be weaker in a practical application, but still adequate for feed-back control of product composition.

Fig. 10.5. Spectral distribution of the t-statistic for the correlation of fluorescence emission with skin content (line), gel strength (solid squares) and cooking losses (empty squares) in mixtures of chicken breast meat and skin.

One of the problems in calibration is pseudofluorescence - reflectance of the upper edge of the excitation band-pass. This occurs because excitation and emission maxima are fairly close, and the filters and dichroic mirrors used to separate excitation from emission are not perfect. Thus, the standard used to calibrate the apparatus for the measurement of relative fluorescence should have a similar reflectance to meat. Clean aluminium foil with a dull surface is a fairly close match to meat.

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Risk Assessment of Irradiated Foods

Ioannis S. Arvanitoyannis , Nikoletta K. Dionisopoulou , in Irradiation of Food Commodities, 2010

Beef

Research was performed to extend ground beef retail display life using antioxidants, reductants, and/or total aerobic plate count (TSP) treatments combined with e-beam irradiation. Half of the treated samples were irradiated at 2.0 kGy absorbed dose under a nitrogen atmosphere, and half remained non-irradiated. Samples were displayed under atmospheric oxygen and evaluated for TPC, thiobarbituric acid reactive substances (TBARS), and instrumental color during 9 days of simulated retail display (SRD). Treated irradiated samples were just as red and vivid on SRD Day 9 as the non-irradiated untreated control at Day 0 ( Duong et al., 2008).

Escherichia coli O157:H7 can contaminate raw ground beef and cause serious human foodborne illness. Although lag phase duration decreased from 10.5 to 45°C, no lag phase was observed at 6, 8, or 10°C. The specific growth rate increased from 6 to 42°C and then declined up to 45°C. In contrast to these profiles, the maximum population density declined with increasing temperature, from approximately 9.7 to 8.2 log CFU/g (Tamplin et al., 2005).

The inactivation kinetics in the death of Listeria innocua NTC 11288 (more radioresistant than five different strains of L. monocytogenes) and Salmonella enterica serovar Enteritidis and S. enterica serovar Typhimurium by e-beam irradiation has been studied in two types of vacuum-packed RTE dry fermented sausages ("salchichon" and "chorizo") in order to optimize the sanitation treatment of these products. Therefore, this treatment produces safe, dry fermented sausages with similar sensory properties to the non-irradiated product (Cabeza et al., 2009).

Moist beef biltong (mean moisture content, 46.7%; a w, 0.919) was vacuum packaged and irradiated to target doses of 0, 2, 4, 6, and 8 kGy. TBARS measurements and sensory difference and hedonic tests were performed to determine the effect of γ-irradiation on the sensory quality of the biltong. Although lean moist beef biltong can thus be irradiated to doses up to 8 kGy without adversely affecting the sensory acceptability, low-dose irradiation (64 kGy) is most feasible to optimize the sensory quality (Nortjé et al., 2005).

E-beam and X-ray irradiation (2 kGy) inactivated E. coli O157:H7 below the limit of detection, whereas hydrostatic pressure treatment (300 mPa for 5 min at 4°C) did not inactivate this pathogen. Solid-phase microextraction was used to extract volatile compounds from treated ground beef patties. Irradiation and hydrostatic pressure altered the volatile composition of the ground beef patties with respect to radiolytic products. However, results were inconclusive regarding whether these differences were great enough to use this method to differentiate between irradiated and non-irradiated samples in a commercial setting (Schilling et al., 2009).

The effect of γ-irradiation (4 and 9 kGy) and packaging on the lipolytic and oxidative processes in lipid fraction of Bulgarian fermented salami during storage at 5°C was evaluated (1, 15, and 30 days). No significant differences were observed in the amounts of total lipids, total phospholipids, and acid number within the vacuum-packed samples of salami treated with 4 and 9 kGy during storage. The changes in TBARS depended mainly on the irradiation dose applied and did not exceed 1.37 mg/kg in all groups (Bakalivanova et al., 2009).

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Reducing fats in processed meat products

Barbut S. , in Processed Meats, 2011

14.3 Consequences of reducing fat in processed meats from an organoleptic and functional perspective

As indicated earlier, a straight fat reduction in ground beef-type patties to 10% or below, results in an inferior product. Reitmeier and Prusa (1987) also reported that as fat level was reduced, in pork patties from 23 to 4%, the product became less tender and juicy and had a lower oily mouth coating. Pork flavor was less pronounced in the 4% fat patties. As observed with the beef patties, fat reduction by itself will not likely produce a palatable low-fat pork sausage. The authors suggested that additional ingredients be tried/used to enhance the eating quality of reduced fat products.

In a comminuted-type sausage, Bishop et al. (1993) reported that replacing fat (15% of the 30%) with added water prevented the increase in firmness normally associated with low fat bologna. However during storage, accumulated purge in vacuum packages increased with water content in the products, and also with the use of pre-emulsified oil. In terms of modifying processing methods, the authors also tried pre-emulsifying the fat or oil. They indicated that it helped to decrease the firmness of low fat bologna. The color was darker for all the reduced fat bologna except the one pre-emulsified with corn oil. Flavor and overall acceptability scores, from a consumer sensory panel, did not differ among bologna samples, but juiciness scores were higher in bologna containing additional water.

Huffman and Egbert (1990) reported that beef patties produced with approximately 20% fat were highest in overall acceptability over a fat content ranging from 5 to 25%. When changing the particle size they noted that overall palatability of low fat ground beef was slightly improved by a final grind through a 0.48   cm (3/16 inch) plate rather than the more common 0.32   cm (1/8 inch) plate.

Huffman and Egbert (1990) and Egbert et al. (1991) have also evaluated the use of a carrageenan gum, in a large-scale study, targeted to bring a new low fat product to the market. They compared beef patties containing 20% fat with those with 8% fat with or without 0.5% iota carrageenan, 10% water, 0.4% encapsulated salt and 0.2% hydrolyzed vegetable proteins. Broiled carrageenan patties with 8% fat were rated more tender by a sensory panel and contained 16% more moisture, 58% less fat, 16% (14   mg/100   g) less cholesterol and 37% (100   kcal/100   g) fewer calories than the 20% fat control. Reducing the fat content to 8% without any additives resulted in patties that were less juicy, had lower flavor intensity, and greater shear force values than either the 20% control or 8% fat-carrageenan patties. Patties with 20% fat had the highest cooking losses but lowest shear force. Serving temperature also appeared to be more critical for low-fat patties than regular fat patties. The McDonald's Corporation adapted a low fat carrageenan formulation pretty similar to the one described by Huffman and Egbert (1990) and introduced the McLean Delux™ hamburger in 1991. The product was on the market for several years but then removed, probably due to low sale volumes. It is interesting to note that in consumer surveys, most people would indicate that they would like to buy low fat hamburgers (e.g., when asked in focus groups), but when they enter a fast food restaurant they would actually like to have a more juicy/full flavor hamburger. Since the 1991 introduction, there has been quite a lot of development done in this area by various meat and/or ingredient companies and quality has dramatically improved, but the McLean has not been re-introduced. Overall, the application of any gum : water substitution combination (e.g., water : carrageenan) must be carefully done, otherwise unexpected product changes can negatively affect acceptability. For example, when using carrageenan one must remember that it has a low melting point and it forms a reversible gel (melts at about 50   °C). This can cause premature moisture loss and/or water-soluble flavors; fewer browning reaction products may develop during grilling/broiling, thus reducing meaty flavor (both just after cooking and more so after holding under a fast-food service situation). This is on top of natural variations in carrageenan performance (e.g., the gum is extracted from seaweeds at different locations around the world, refined by different processes, and is affected by the presence of mono- and divalent salts).

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FREEZING | Structural and Flavor (Flavour) Changes

C. James , S. James , in Encyclopedia of Food Sciences and Nutrition (Second Edition), 2003

Freezing rate

The effect of variations in freezing rate on the tenderness of ground beef patties has been investigated using conditions which achieved freezing times to −18  °C of 24, 48, 72, and 97   h. In one study, immediately after freezing, patties frozen in 24   h were less tough than those frozen in 96   h (Table 1). This difference was still found after 6 months storage. After 18 months, patties frozen in 48   h were tenderer than those frozen at faster or slower rates. Slight reductions in flavor and juiciness were also found in patties frozen in 96   h. Taste panel and sensory scores for the tenderness of ground beef patties frozen in air at −43   °C were higher than for those frozen at −20   °C. Freezing rates were not detailed, and patties were stored for 2 weeks at −30   °C.

Table 1. Effect of freezing rate on tenderness of ground-beef patties (ranging from 1, extremely tough, to 8, extremely tender)

Storage time Freezing rate (hours to −18   °C)
24 48 72 96 SE
Just before freezing 6.1 d 5.6 f 5.8 e 6.0 d 0.03
Just after freezing 5.1 d 4.7 d,e 4.8 d, e 3.7 e 0.25
  6 months 4.9 d 4.9 d 4.2 e 4.3 e 0.10
  18 months 4.5 e,f 5.2 d 4.7 d,e 4.1 f 0.09

From Berry BW and Leddy KF (1989) Effects of freezing rate, frozen storage temperature and storage time on tenderness values of beef patties. Journal of Food Science 54: 291–296.

a, b, c, d, e, f
The same letters indicate no statistical differences.

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CHEMICAL AND PHYSICAL CHARACTERISTICS OF MEAT | Color and Pigment

S.P. Suman , P. Joseph , in Encyclopedia of Meat Sciences (Second Edition), 2014

Premature Browning

Premature browning (PMB) is the phenomenon observed in cooked ground beef wherein myoglobin denaturation occurs at a temperature lower than that is required to destroy foodborne pathogens. Because the dull-brown color of cooked beef is often considered as an indicator of doneness, PMB can lead to food safety concerns. The thermal denaturation temperatures are different for myoglobin redox forms, and therefore the incidence of PMB is influenced by the predominant redox form of myoglobin in beef before cooking. The resistance of myoglobin redox forms to thermal denaturation is in the order: deoxymyoglobin>oxymyoglobin>metmyoglobin. Processing strategies that increase the proportion of oxymyoglobin and metmyoglobin in beef, such as oxygen-rich packaging (high-oxygen MAP and aerobic packaging), thawing frozen beef, and bulk packaging, increase the incidence of PMB. In these cases, meat pigments are exposed to oxidative conditions before cooking, causing accelerated pigment denaturation during cooking. However, antioxidants and vacuum packaging increase the relative proportion of deoxymyoglobin and thus minimize PMB. Ground beef packaged in CO MAP demonstrates a low incidence of PMB, presumably due to the increased resistance of carboxymyoglobin pigment to oxidative environments and/or due to the pink-red denatured globin CO hemochrome resulting from the cooking of CO-treated beef.

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