Graham Gardner

In this studies a prototype low cost portable handheld microwave system (MiS) designed and tested for back fat depth measurements using non-invasive techniques on lamb carcase in commercial abattoirs. For this application, two different type antennas was designed and tested. These results demonstrate the capacity of this prototype MiS system together with proposed antennas to estimate fat depth at the C site in lamb carcasses non-invasively in commercial abattoir at rate 100 carcase in 30 minutes.

Non-invasive and non-destructive measurements of fat depth are sought after within the beef industries, as overfat carcases cause significant economic loss and wastage for processors. Within the Australian beef industry fat depth is measured manually, however this has the disadvantage of being destructive, subjective and time-consuming [1]. Since biological tissues in animals, feature a high contrast in their dielectric properties (skin, fat, and muscle) at microwave frequencies [2], this represents an opportunity to different fat from lean and thus estimate fat depth and body composition of carcases and live animals. This concept has been tested in lamb carcases where a low-cost portable Microwave System has been developed for measuring C-site back fat depth [3]. This paper details the testing of a similar device in beef, where we hypothesised that it would accurately predict P8 and rib fat depth in beef carcases.

In the meat industries, overfat carcases cause significant economic loss due to the labour required for trimming fat, and the waste that it represents. Fat is the most variable component, both in its amount and distribution in the carcase, and on this basis the measurement of carcase fat depth is the cornerstone of most carcase classification schemes for beef, lamb and pork worldwide [1,2]. Fat depth is often measured manually, however this has the disadvantage of being destructive, subjective and time-consuming. The ability to estimate fat depth accurately via a non-invasive and non-destructive technique is therefore highly sought after [3]. One solution showing considerable promise for determining carcase fatness is a Microwave System (MiS) using low power non-ionizing electromagnetic waves [4]. Since biological tissues in animals, feature a high contrast in the dielectric properties (skin, fat, muscle and bone) at microwave frequencies [4], MiS can accurately evaluate the fat depth and body composition of carcases and live animals. As an illustration of tissue parameters, the range of contrast available in X-ray imagery within soft tissues is less than 2%; whereas within microwave electromagnetic fields the range in relative dielectric constant goes from a minimum of about 4 in fat to a maximum of about 70 in muscle [5]. Furthermore, the microwave devices required to produce and measure these fields are low cost and highly portable. Working within these constraints a low-cost portable Microwave System has been developed for measuring back fat depth in lamb carcases. This paper details early testing of this device, testing the hypothesis that it will provide a reliable estimate of back-fat depth in lamb carcases.

The USA and China are Australia’ s strongest sheep meat export markets , however insights into consumer perceptions of Australian sheep meat are limited . IMF and shear force are good indicators of eating quality for Australian consumers however the relationship for American and Chinese consumers is unknown. Eating quality scores (tenderness, juiciness, liking of flavour, and overall liking) were obtained from American, Australian, and Chinese consumers for Longissimus lumborum and semimembranosus muscles collected from Australian sheep (n=328). Shear force was negatively associated with all sensory traits, consistent for all countries. Whereas, increasing IMF levels had a positive impact on all eating quality scores for all countries, however the most significant change was observed for Australian consumers indicating their higher sensitivity towards IMF differences.

This study tested the palatability of lamb meat derived from pasture versus grain finishing systems. The loin and topside muscles from 105 lambs were collected. Sensory scores were generated using untrained consumers who tasted 5 day aged grilled steaks, scoring tenderness, juiciness, flavour and overall liking. Consumer scores did not differ in female lambs fed grain or pasture diets. However in wether lambs palatability scores for overall liking, tenderness and juiciness were higher for those on grain compared to those on pasture. Correcting for intramuscular fat accounted for most of these differences. These results confirm that Australian consumers do prefer grain-fed lamb meat, but only in wether lambs.