Milk and dairy products can have variable contents of antioxidant compounds that contribute to counteract the oxidation of lipids and proteins during processing and storage. The content of active antioxidant compounds is closely linked to their protection by oxidation. Freezing is one of the factors that can reduce antioxidant activity. Freezing of milk or curd is frequently used in case of the seasonality of milk production and/or seasonal increased demand for some products. In this paper, the effect of using frozen curd on the oxidative stability of buffalo Mozzarella cheese was evaluated. Samples of buffalo Mozzarella with different frozen curd content (0%, 5%, 20%, and 50%) were produced and analyzed at one and nine days. Mozzarella cheese with higher frozen curd content had a significant increase in redox potential parallel to the decrease in antioxidant activity, showing less protection from oxidation. Lipid and protein oxidation, expressed respectively by malondialdehyde and carbonyl content, increased significantly with increasing frozen curd. At nine days, carbonyls significantly increased while malondialdehyde content did not vary, showing that during storage, fat was more protected from oxidation than protein. The average carbonyl levels were comparable to those of some cooked cheeses, and the malondialdehyde levels were even lower. The results of this study stimulate the investigation of new strategies to decrease the oxidative damage in cheeses produced in the presence of factors decreasing oxidative stability.

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CONTEXTLivestock production, and more particularly ruminants, is criticized for its low conversion efficiency of natural resources into edible food. OBJECTIVEThe objectives of this paper are to propose an evaluation of the contribution to food security of different European cattle farms through three criteria: 1) food production assessed by the amount of human-edible protein (HEP) and energy (HEE) produced at farm level, 2) feed-food competition at the beef production scale estimated in terms of net human-edible protein and energy and in terms of land used, and 3) food affordability assessed by the production cost of meat, protein and energy. METHODSThe analysis is based on 16 representative beef production systems in France, Belgium, Ireland, Italy and Germany and covers cow-calf systems, finishing systems, dairy and mixed dairy-finishing systems, with or without cash crops. RESULTS AND CONCLUSIONSThe results show that, at the farm level, systems producing both beef and milk or cereals have higher HEP and HEE production per hectare (up to 370 kg of HEP and 60000 10 6 J.ha -1 ) than specialized beef systems (up to 50 kg of HEP and 1600 10 6 J.ha -1 ) and have lower production costs (approximately €6 kg -1 of HEP in mixed beef system and €29 kg -1 of HEP in a specialized cow-calf-fattener system). Beef systems are almost all HEE net consumers. Results are more variable concerning net HEP efficiency. The cow-calf enterprises are mostly net producers of HEP but, in order to produce human edible meat, these systems need to be combined with finishing systems that are mostly net consumers of HEP. In most cases, cowcalf-finishing systems are net consumers of HEP (between 0.6 and 0.7) but grass-based systems using very little concentrates or systems using co-products not edible by humans are net HEP producers. The grass-based systems use more land area per kilogram of carcass but a major part of this area is non-tilled land, thus these systems are not in direct competition with human food production. The lowest meat production costs are the finishing systems producing the most live weight per livestock unit (LU) per year and dairy systems in lowland which share the costs between milk and meat. SIGNIFICANCEAlthough most of HEE and HEP efficient farms typically have higher meat production costs, some grassland based systems stand out positively for all indicators. These results pave the way for improvements of the contribution of beef production systems to food security.

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The present study aimed to determinate beef meat shelf-life packaged in modified atmosphere (MAP). The experiment was carried out on young bulls Longissimus dorsii muscle and considered 2 thesis (meat portioned and conserved in MAP after 3 days “NA” and after 7 days “7A” of ageing), 2 types of packaging (with or without water absorbent pad) and 3 different conservation times (3, 7 or 11 days). The analysis regarded: water loss, colour, TBArs and protein ossidation. Liquid loss showed higher value in packaged meat with absorbent pad than the other (10.38% vs 2.42% P<0.001), while the evaporate liquid was highest in no absorbent pad samples. The positive effect of pad was found in metmyoglobin percentage (13.98 vs 15.10 % respectively for its presence and absence) and protein oxidation (67.32 vs 79.26 nmol thiol/mg protein P<0.05). TBArs increased with conservation times from 0.88 to 2.57 mg/100g, while it didn’t show differences between the two thesis and the two different packaging methods. In conclusion the use of absorbent pad improved meat nutritive quality despite produced more water loss