There have been many attempts to increase n-3 fatty acids (FA) in beef due to their health benefits and their presence in ruminant animals [1]. However, when polyunsaturated fatty acids are too abundant, oxidation can result in a shorter shelf life and negative flavours or off-flavours in cooked meat. Vahmani et al. [2] improved the profile of health favourable FA (n-3, vaccenic and rumenic) in beef by feeding co-extruded flaxseed (flaxseed, peas, and alfalfa) before alfalfa-grass hay. However, this beef enriched with healthful FA resulted in tougher steaks with lower beef flavour and greater off-flavour intensity, presenting a fishy offflavour to an extent that might be detectable by consumers [3]. The aim of this study was to characterize the volatile compounds responsible for the fishy off-flavour found in beef with health enhanced FA profiles.

Consumption of central nervous system tissue (CNST) from cattle with bovine spongiform encephalopathy (BSE) is thought to cause the human neurological disease, variant Creutzfeldt-Jacob disease. To identify points of cross-contamination of beef carcasses with CNST, 55 young beef cattle were slaughtered and processed through a federally inspected multispecies abattoir. The objectives of this study were to evaluate CNST spread following the placement of a plug in the penetration site of the skull after captive bolt stunning, to evaluate cross-contamination of carcasses before and after splitting, to compare the effects of hot water pasteurization (84°C for 10 s) versus cold water wash (10°C for 30 s) for reducing CNST on the carcass, and to examine other possible sources of cross-contamination in the abattoir. Results indicated that the use of a plastic plug reduced CNST contamination near the bolt penetration site. This study also confirmed that carcass splitting resulted in an increase in CNST contamination at various areas of the carcass. Hot water pasteurization appeared to be an effective means of removing CNST contamination from carcasses in most of the areas sampled.

The effects of tissue antioxidant levels on formation of heterocyclic amines (HAs) and their mutagenicity in grilled lean beef were studied. Meat from 54 feedlot steers fed different levels of vitamin E (340, 690, 1040 and 1740 IU/animal/day) for 120-days was used to provide beef with different levels of antioxidants (α-tocopherol). Prevalent HAs were then analyzed by HPLC using UV/Fluorescence detection. Five major HAs were found: 2-amino-3,8-dimethyl-imidazo(4,5-F)Quinoxaline (MeIQx), 2-amino-3,4,7,8-tetramethyl-imidazo(4,5-F)Quinoxaline (TriMeIQx), ß-Carboline-9H-Pyrido[3,4-b]indole (Norharmane), 1-Methyl-9H-pyrido[3,4-b]indole (Harmane) and 2-amino-1-methyl-6-phenylimidaza(4,5-B)pyridine (PhIP). Total content of HAs in grilled lean beef ranged from 9.57 ng/g to 11.59 ng/g. There was, however, a trend (P=0.097) found for reduced mutagenicity with increasing tissue levels of α-tocopherol. The increasing dietary vitamin E significantly increased the α-tocopherol level in lean beef (P<0.001), but it had no significant (P>0.05) inhibitory effects on the content of individual and total HAs.

Juárez, M., Dugan, M. E. R., Larsen, I. L., Thacker, R., Rolland, D. C. and Aalhus, J. L. 2011. Oxidative stability in grinds from omega-3 enhanced pork. Can. J. Anim. Sci. 91: 623–634. In order to investigate the effect of enhancing n-3 fatty acid levels in carcasses on the retail and sensory characteristics of pork grinds, as well as the ability of increasing dietary levels of vitamin E to stabilize the increase in PUFA levels from flaxseed supplementation, 81 pigs were used in a 3×3 factorial experiment. Dietary treatments included three lengths of time (0, 3 and 6 wk) of flaxseed supplementation and three levels of vitamin E (40, 200 and 400 mg kg feed−1). α-Tocopherol tissue levels increased with dietary vitamin E supplementation (P<0.001), and fat softness (P=0.018) and total PUFA and n-3 fatty acids (P<0.001) increased with flaxseed supplementation. Most other animal performance, carcass and lean pork quality traits were not affected (P>0.05) by dietary treatments. In ground pork, the increase in TBARS after 6 d in retail was lower (P<0.001) with increasing dietary vitamin E levels. However, vitamin E had no effect (P>0.05) on the higher (P<0.001) TBARS levels observed in grinds from flaxseed fed pigs. The dietary addition of flaxseed negatively modified (P<0.05) all the sensory attributes of both cooked and reheated products. Increasing the fat content of the grinds up to 30% seemed to counteract (P>0.05) the negative effects of feeding flaxseed for 3 wk. Feeding vitamin E was not able to prevent negative effects (P<0.05) observed during retail display in grinds with either increasing fat content or higher n-3 fatty acids from dietary flaxseed. However, increasing dietary vitamin E only showed a protective effect (P<0.05) on retail appearance after long periods of ageing.

Micellar electrokinetic chromatography (MEKC) with laser-induced fluorescence (LIF) detection was used for internal standard (pyrrolidinol) based quantification of 4-hydroxyproline (Hyp) in muscle hydrolysates. Hydrolysates were first derivatized with o-phthaldialdehyde to reduce primary amine interference and then 4-chloro-7-nitrobenzo-2-oxa-1,3-diazol (NBD) to enable selective detection of secondary amines. This method allows for rapid and sensitive detection of hydroxyproline in dilute hydrolysates using commercially available capillary electrophoresis equipment.