Economic feasibility evaluation of microfiltration of milk prior to cheesemaking.
A nonlinear programming optimization model was used to evaluate the net revenues and potential profit-ability of microfiltration (MF) prior to cheesemaking in the 3-year period 1998 to 2000, using monthly milk price and composition data. The model identifies the optimal mix of milk resources and determines if MF cheesemaking produces a higher net revenue than conventional cheesemaking that uses NDM and condensed milk for fortification. This study demonstrates the potential of this model to evaluate new technologies in cheese manufacture and improve decision making in the cheese industry. The use of MF produced higher net revenues in 30 out of the 36 mo for both Cheddar and low-moisture, part-skim mozzarella, leading to an appreciable increase in net revenue (vs. conventional cheesemaking) for both cheeses. The benefit from MF in net revenue was greater when the cream price was high. The use of 3X MF yielded the same net revenue as 2X MF. An estimate of manufacturing costs of MF vs. conventional cheesemaking was also made. To this end, the yields of products were calculated by the optimization model, while the production cost of each product was estimated from data of two economic engineering studies and a MF cheesemaking trial. The manufacturing cost of MF Cheddar was slightly higher than the manufacturing cost of conventional Cheddar. However, the benefit in net revenue from the use of MF was estimated to be higher than the difference in manufacturing costs. Moreover, some advantages in the new coproducts of MF Cheddar could outweigh its higher manufacturing cost. The relationships between prices and recoveries of coproducts required to render MF profitable were identified.
Characterising ripening in UF-cheese
Abstract It is possible to manufacture several varieties of cheese from milk concentrated by ultrafiltration (UF-cheese). Often, the UF-cheese types are divided into three categories: (1) cheese from maximum two-fold concentrate, (2) cheese from approximately five-fold concentrate, and (3) cheese from fully concentrated milk. The most fundamental characteristic of UF-cheese is its content of whey protein. UF-cheese in category 1 ripens more or less similarly to traditionally produced cheese. It is well known, however, that the ripening of UF-cheese from five-fold or fully concentrated milk proceeds much more slowly. This means that protein breakdown and flavour development are retarded relative to traditional cheese, even though the overall composition of the cheese (total solids, TS, fat in dry matter, FDM) is the same. Many studies on this phenomenon have demonstrated that this is due mainly to a very slow breakdown of β-casein in the UF-cheese. The primary hydrolysis of β-casein is catalysed partly by plasmin. Much evidence suggests that the action of plasmin in UF-cheese is inhibitted by β-lactoglobulin and that this is one of the reasons for the slower ripening of UF-cheese. An understanding of the reasons for the slower ripening of UF-cheese opens up the possibility of improving flavour development in such cheese. Studies have shown that it is possible to influence flavour development by using starter strains selected for this purpose, by addition of the correct amount of rennet, by addition of proteolytic enzymes or attenuated starters or by increasing the available amount of plasmin by the addition of a plasminogen activator.
Food security among asylum seekers in Melbourne
Objectives: This research explores food insecurity among asylum seekers who are members of the Asylum Seeker Resource Centre (ASRC) in Melbourne, Australia.