Energy Efficiency in Meat Processing

Meat Processing: Overview

Meat and meat products are rich sources of nutrients including, fats, proteins, vitamins (vitamin B12) and minerals (zinc and iron) and forms an essential part of the diet and consumed across in many parts of the world (FAO, 2012). Ritchie and Roser (2018) highlighted that global meat production had increased 4-5 folds since 1961 and the Figure 1 depicts that movement. However, this trend of meat production and consumption is on the rise in both developing and developed nations.

Figure 1.

Total meat production in tonnes excluding offal & slaughter fats

(Ritchie & Roser, 2018)

Meat production by livestock type has also changed dramatically since 1961 as shown in the Figure 2.

Figure 2.

Meat production by Livestock Type

(Ritchie & Roser, 2018)

Slaughtering of livestock is an important industry in most of the countries to produce meat and meat products. It involves stunning, bleeding, dehiding, dehairing/defeathering, evisceration, dressing and washing. Depending on the customer requirements it may also involve the deboning process (Hui, 2012). During the slaughtering process both edible (e.g. livers, gizzards) and inedible products (e.g. hides, feathers) are produced. Figure 3 presents a flowchart for the basic processes involved in slaughtering and processing of beef.

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  Reception of Beef Cattle: Beef cattle are delivered on a specially designed lorries to the slaughterhouse and kept in the holding area where cattle are washed and rested for one or two days.

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  Stunning and Bleeding: The cattle are led to the stunning area where they are stunned using electric shock or bolt pistol to make animal unconscious without any discomfort or excitement. They are then chained by their rear legs and mounted on overhead rail. Using a sharp blade their carotid arteries and jugular vein are severed to allow all the blood present in the animal to flow out in a trough.

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  Dressing: In this process unwanted parts such as skin, head, hair and hoofs are removed using machines in larger slaughterhouses or by hand in smaller operations. Antimicrobial interventions such as hot/ambient water wash, organic acid wash, steam vacuuming and bunging is carried out on the carcass to reduce the microbial activity. Steam vacuuming is used to remove any contamination from the carcass and bunging is to avoid contaminating the carcass with faecal material.

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  Evisceration: Evisceration is the process to remove internal organs from the carcass. Care must be taken so that internal organs such as stomach and intestines are carefully separated without contaminating the carcass with faecal material.

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  Splitting: In this stage the carcass is split with a saw which allows inspection of the carcass for any disease conditions which can be unfit for human consumption.

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  Trim Rail: Carcass parts which are undesirable or parts which possesses quality issues are removed by trimming.

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  Final Wash & Chilling: In this step the carcass undergoes final wash to remove any further contaminations. The carcass is weighed, marked, branded and sent to chillers. Sending it to the chillers inhibit the growth of harmful microbial pathogens. Appropriate temperatures are maintained in the chillers to ensure quality and safety of the carcass.

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  Cutting and Boning: At this point the carcass is chopped or deboned as per the customer requirements and packed.

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  Packaging, Storage and Distribution: This is the final step where product is packaged with correct specifications (expiry date, description), stored and sent for distribution.