Kenneth McMillin

Where is MAP Going? A review and future potential of modified atmosphere packaging for meat.

Modified atmosphere packaging (MAP) is the removal and/or replacement of the atmosphere surrounding the product before sealing in vapor-barrier materials. While technically different, many forms of MAP are also case-ready packaging, where meat is cut and packaged at a centralized location for transport to and display at a retail store. Most of the shelf life properties of meat are extended by use of MAP, but anoxic forms of MAP without carbon monoxide (CO) do not provide bloomed red meat color and MAP with oxygen (O(2)) may promote oxidation of lipids and pigments. Advances in plastic materials and equipment have propelled advances in MAP, but other technological and logistical considerations are needed for successful MAP systems for raw chilled fresh meat. Current MAP options of air-permeable overwrapped trays in master packs, low O(2) formats of shrunk film vacuum packaging (VP) or MAP with carbon dioxide (CO(2)) and nitrogen (N(2)) and their peelable barrier film derivatives, and high O(2) MAP each have advantages and disadvantages. Packaging technology innovations and ingenuity will continue to provide MAP that is consumer oriented, product enhancing, environmentally responsive, and cost effective, but continued research and development by the scientific and industry sectors will be needed.

Effects of Postmortem time of calcium chloride injection on beef tenderness and drip, cooking, and total loss

The effect of postmortem time of calcium chloride (CaCl(2)) injection in conjunction with postmortem aging was determined on 16 beef semimembranosus muscles. Each muscle was cut into four equal segments that were randomly assigned: (1) no injection (control); (2) CaCl(2) at 1 h postmortem; (3) CaCl(2) at 12 h postmortem; or (4) CaCl(2) at 24 h postmortem. Samples were injected with a 0·3 m solution of CaCl(2) at 10% by weight. At 24 h postmortem, each segment was divided into two pieces that were randomly assigned to either a 10-day aging period (2°C) or to frozen storage (-29°C). Shear force values were higher (P < 0·01) in control samples compared with injected samples and increased linearly (P < 0·05) with time of injection. Drip loss was lower (P < 0·01) in control samples compared with injected samples. A linear (P < 0·05) effect was found for the increases in cooking and total loss due to injection time. Aging decreased (P < 0·05) shear force values and cooking loss. CaCl(2) injection at 1 h postmortem was most effective in reducing shear force values and preventing excessive moisture loss. However, injection at 12 or 24 h postmortem was also effective in lowering shear force values.

Quality and Shelf-Life of Meat in Case-Ready Modified Atmosphere Packaging

Case-ready packaging of meat in a central location involves minimal package or product manipulation before retail sale. Dynamic gas exchange modified atmosphere packaging (MAP) is the replacement of the package gaseous environments through passive or active means during storage or for display. Passive systems rely upon removal of external barrier materials or changes in film permeability to cause diffusion of different gases into the package. Active systems physically replace the package gases with mixtures of a different composition. Use of CO, increases inhibition of microorganisms more than vacuum techniques. Incorporation of O, into gas mixtures will cause formation of bloomed oxymyoglobin pigments, but microorganism growth and lipid stability may be influenced. Case-ready packaging using anoxic environments for storage of meat that are exchanged for those with higher levels of oxygen before retail display gives storage life generally equivalent to conventional systems of primal cut vacuum packaging while providing extended display life compared with air-permeable over-wrap packaging. Postmortem fabrication time, gas mixture compositions, and type of products influence the color, lipid stability, microorganism growth, drip loss, formation of radical oxidation initiator compounds, and metmyoglobin reducing activity of meat in gas exchange MAP. This technique may also be useful for incorporation of aerosols or gases to inhibit or destroy pathogenic microorganisms on the surface of cuts or ground meats

Effects of electrical stimulation and temperature on beef quality and tenderness.

Beef carcasses were stimulated with either 50 or 500 V and exposed to three chilling temperatures during the first 3 to 9 h post mortem. Both high (HV) and low voltage (LV) electrical stimulation (ES) treatments improved lean maturity scores, lowered the pH values at 2 h through 12 h and reduced the time required for the ATP level to reach minimum values. Both HV-ES and LV-ES treatments influenced firmness, fragmentation and connective tissue (CT) residue as measured by sensory panel and reduced Instron shear value (ISV) of loin steaks. The 30°C temperature treatment had an adverse effect while the 20°C temperature treatment had a beneficial effect on ISV and panel ratings for firmness and CT residue. There was an interaction between conditioning treatments and ES for ISV and sensory panel traits. The LV-ES-20C treatment resulted in the lowest ISV and superior panel ratings; however, the LV-ES-30C treatment had ISV and sensory panel ratings that were similar to the NES-2C (control) group.

Advancements in meat packaging

Packaging of meat provides the same or similar benefits for raw chilled and processed meats as other types of food packaging. Although air-permeable packaging is most prevalent for raw chilled red meat, vacuum and modified atmosphere packaging offer longer shelf life. The major advancements in meat packaging have been in the widely used plastic polymers while biobased materials and their integration into composite packaging are receiving much attention for functionality and sustainability. At this time, active and intelligent packaging are not widely used for antioxidant, antimicrobial, and other functions to stabilize and enhance meat properties although many options are being developed and investigated. The advances being made in nanotechnology will be incorporated into food packaging and presumably into meat packaging when appropriate and useful. Intelligent packaging using sensors for transmission of desired information and prompting of subsequent changes in packaging materials, environments or the products to maintain safety and quality are still in developmental stages.

The relationship between ATP and R-values in postmortem bovine Longissimus dorsi muscle

To study the relationship between ATP and each of three R-values (R248, R250 and R258) in beef longissimus dorsi muscle data, appropriate mathematical functional forms were estimated by the Box-Cox transformation and then tested for linearity. Two separate tests for linearity indicated that the relationships between ATP and the three R-values were nonlinear. A shifting parameter restriction on the Box-Cox model was used to produce a curve that was more parallel to the y axis in the lower range of x axis, but the restriction lowered the R(2) compared with the Box-Cox model. ATP (1 μmol) could be estimated by R248 of 0·925, R250 of 0·967 and R258 of 1·038 with standard errors of 0·033, 0·034 and 0·032, respectively. There were no significant differences among the three R-values for the prediction of ATP, but there was a suggestion that R258 was the preferred R-value for predicting ATP in beef muscle.

Producer perceptions of important challenges currently facing the United States meat-goat industry

There is an apparent increase in demand for goat meat in the United States, perhaps because of recent immigrants and population growth. This is driving an increase in meat-goat production. This paper addresses the importance of 11 challenges faced by United States meat-goat producers, with results having implications for research, extension, and teaching efforts by universities, governmental agencies, and industry. A survey of meat-goat producers was conducted. Differences in opinion as to the importance of challenges by industry segment were analyzed using ordered probit models. The 4 items selected by producers as the most important challenges facing producers were high cost of goat production, lack of a clear marketing system for goats, lack of a goat meat processor close by, and internal parasites. Others of note were the lack of a grading system for goats, pasture management problems, diseases, and insufficient government support for the industry.

Intramuscular Fat Characteristics of Namibian Common Eland (Tragelaphus oryx)

The influence of sex on the intramuscular fat characteristics of eland harvested from the highland savanna in Namibia was investigated. No significant differences were observed between sexes for moisture, protein and ash content in the longissimus dorsi et lumborum (LDL). Fat content in LDL differed (P = 0.022) for male (1.2%) and female (2.0%) eland. Stearic acid was the most abundant fatty acid (26.1%) in males and differed from females (21.7%) whilst oleic acid was the most abundant fatty acid (39.1%) in females. Females contained more MUFA (41.6%) than males (26.4%). Eland had a PUFA to SFA ratio of 4–5. Males did not differ from females for the n-6:n-3 ratio (2.7–2.9). No significant differences for sex were observed in cholesterol content. The chemical composition of eland can serve as a reference standard for future studies as well as be of value for food labelling and marketing strategies.

Breeding Technologies in U.S. Meat Goat Production: Who Are the Adopters and How Does Adoption Impact Productivity?

Adoption of advanced breeding technologies and management practices (BTMP) in U.S. meat goat production and their impact were examined. Adopters generally had larger-scale operations, used rotational grazing and/or dry lot systems, and sold larger percentages of animals for breeding and show purposes. Farmer demographics and farm variables also influenced adoption. Complementarity of adoption was found—adopters of one BTMP tended to adopt other BTMPs. Measures of productivity and profitability were not affected by adoption. Goat breed, farmer experience, production system used, and specialization influenced productivity, and farm size had the greatest influence on enterprise profitability.

Influence of Energy and Protein Supplementation on Growth Rate, Empty Body Composition and Ruminal and Blood Metabolites of Goat Kids Fed Hay Diets1

A comparative slaughter experiment was conducted with 28 Spanish kids (BW = 20.6 kg) fed a hay-based diet to determine the effects of supplemental energy and protein on growth rate, body composition, and ruminal and blood metabolites. After 84 d, kids were harvested, digesta contents removed and empty body weighed and ground. Samples were freeze-dried and analyzed for DM, CP, ether extract, ash, and gross energy. All kids had increased BW gains. However, unsupplemented kids lost empty BW and weight of all body components except ash. Kids supplemented with energy or protein increased (P<0.05) empty BW, body water, protein, fat, ash, and gross energy when compared with unsupplemented kids. The percentages of body water and ash decreased (P<0.05) when supplemental energy or protein was fed. The percentage of body protein was reduced (P<0.05) by supplemental energy and unaffected (P=0.81) by supplemental protein. Supplemental energy reduced (P<0.05) ruminal acetate and increased (P<0.05) propionate and butyrate. Supplemental protein increased (P<0.05) concentrations of ruminal ammonia N, plasma urea N, and all ruminal volatile fatty acids. Regression equations suggest that intake of 144 kcal of ME and 6.0 g of CP per kilogram of empty BW0.75 are necessary to maintain empty BW.