Quality cheese

Because of the high total flavor of cheese, the threshold levels of FFAs are higher than for milk or butter. In Cheddar cheese, ADVs of 2.8 3.0 meq/ 100 g fat are usually attained before rancidity is evident (Deeth and FitzGerald, 1975b). Various studies have shown that rancid Cheddar has 2 10 times more FFAs than good quality cheese (Bills and Day, 1964 Ohren and Tuckey, 1969 Law et al., 1976). 

D. Factors that Affect Cheese Quality Cheese Texture... 

As discussed in Section IV, the ripening of cheese, and hence its quality, is due to the activity of microorganisms and enzymes from four or five sources. Therefore, it might reasonably be expected that it should be possible to produce premium quality cheese consistently by controlling these agents however, in spite of considerable research and quality control efforts, it is not yet possible to do so. 

It is generally accepted that calf chymosin produces the best quality cheese. An adequate supply of chymosin from genetically engineered microorganisms is now available and therefore rennet quality should not be a factor in cheese quality. 

Furthermore, probiotics can be included in cheese. Despite the long ripening and shelf life of cheese, probiotic counts appear to be stable in cheese for months. By optimizing fermentation techniques, it is feasible to produce a good-quality cheese with high probiotic counts so that a standard portion of cheese (15 g) provides a dose of at least 10 CFU (Ibrahim et al 2010). 

Figure 3.5 Headspace gas chromatography analysis of volatile fatty acids in Dutch cheese after formation of ethyl esters, (a) High-quality cheese. Chromatographic conditions 10 m x 0.53 mm fused silica column coated with HP-1, 60°C (2 min), 10°C min to 140°C. (b) Poor-quality cheese. Sample thermostatted at 80°C. Reproduced from Osl, F., Bestimmung der niederen freien Fettsauren im Hart- und Schnittkase mit der Head-Space Gaschromatographie, Deutsche Molkerei Zeitung, 45, 1516-18, 1988.

In the dairy industry, lipases are used in the hydrolysis of milk fat. Applications include flavor enhancement of cheeses, acceleration of cheese ripening, manufacture of cheeselike products, and lipolysis of butterfat and cream. Sources of lipases for cheese enhancement are the pancreatic glands or pregastric tissues of lamb, calf, or kid. Each pregastric lipase leads to its own characteristic flavor pattern, and these enzymes are essential in the production of quality cheeses such as Romano and provolone [15]. Pregastric lipases have also been used for the treatment of calf diarrhea or scours [15] and have potential for the treatment of malabsorption syndrome in children. 

Color plays a special role in the foods we eat. For example, when confronted with a food of an unattractive color, the consumer assumes the food is of poor quality or is spoiled. Similarly, a product with an atypical color, e.g., a green cheese or a blue drink, in most cases would be rejected by the consumer. Typically, one associates certain colors with certain food items such as cherry with red, lemon with yellow, and orange with carrot. Therefore, color can serve as a primary identification of food and also as a protective measure to prevent the consumption of spoiled food. Food colors create physiological and psychological expectations and attitudes that are developed by experience, tradition, education, and environment we inevitably eat with our eyes. ... 

The consumption of dairy products plays a significant role in providing high-quality protein, vitamins, minerals, and other bioactive compounds to the American diet. Dairy products are consumed fresh in the United States in the form of fluid milk, cheese, yogurt, butter, and ice cream. Dried and condensed products such as nonfat dried milk, whey, whey protein concentrates, and isolates are also produced which are used as ingredients to boost the nutritional and functional properties of a host of other food... 

Food products can generally be considered as a mixture of many components. For example, milk, cream and cheeses are primarily a mixture of water, fat globules and macromolecules. The concentrations of the components are important parameters in the food industry for the control of production processes, quality assurance and the development of new products. NMR has been used extensively to quantify the amount of each component, and also their states [59, 60]. For example, lipid crystallization has been studied in model systems and in actual food systems [61, 62]. Callaghan et al. [63] have shown that the fat in Cheddar cheese was diffusion-restricted and was most probably associated with small droplets. Many pioneering applications of NMR and MRI in food science and processing have been reviewed in Refs. [19, 20, 59]. 

Recently, organic farms have been encouraged to make added value products such as cheese and yoghurt. The farmer processes the milk and can fix a price for the farmhouse-produced cheese or yoghurt. It needs to be a unique quality product, or have a superior image, if it is going to sell well at a higher price than a similar product in the local supermarket. 

To ensure the safety of food products, representative samples must be inspected so that foodborne bacteria can be identified.15,18,19 Bacteria producing heat-stable enterotoxins, such as Staphylococcus aureus, may be identified by biochemical and serological techniques.20,21 Molecular methods are now widely used for the identification of many pathogenic foodborne bacteria,15,22,23 In addition bacteria used as starter cultures for cheese, yogurt, other fermented foods and beverages, and probiotic dietary supplements may be identified for quality assurance.22,24,25... 

Milk from cows affected with mastitis alters the sensory quality of raw milk and cheese (Munro el al., 1984). Sensory defects are reported as increased rancidity and bitterness, factors which are consistent with higher levels of lipolysis and proteolysis (Ma et al., 2000). 

Vitamin E supplementation has been shown to have positive effects on milk quality in a conventional commercial dairy herd. Milk obtained from cows that received supplemental vitamin E had lower somatic cell counts and plasmin concentrations than corresponding values in milk obtained from control cows. The reduction in plasmin as a result of vitamin E supplementation is very beneficial to the dairy industry because plasmin reduces the cheese-yielding capacity of milk, affects the coagulating properties of milk and its overall ability to withstand processing during cheesemaking (Politis et al., 2004). 

Bertoni G, Calamari L, Maianti M G and Battistotti B (2005), Milk for Protected Denomination of Origin (PDO) cheeses I. The main required features , in Hocquette J H and Gigli S, Indicators of Milk and Beef Quality, EAAP Pub. 112, Wageningen Academic Publishers, The Netherlands. 

NMR is an incredibly versatile tool that can be used for a wide array of applications, including determination of molecular structure, monitoring of molecular dynamics, chemical analysis, and imaging. NMR has found broad application in the food science and food processing areas (Belton et al., 1993, 1995, 1999 Colquhoun and Goodfellow, 1994 Eads, 1999 Gil et al., 1996 Hills, 1998 O Brien, 1992 Schmidt et al., 1996 Webb et al., 1995, 2001). The ability of NMR to quantify food properties and their spatiotemporal variation in a nondestructive, noninvasive manner is especially useful. In turn, these properties can then be related to the safety, stability, and quality of a food (Eads, 1999). Because food materials are transparent to the radio frequency electromagnetic radiation required in an NMR experiment, NMR can be used to probe virtually any type of food sample, from liquids, such as beverages, oils, and broth, to semisolids, such as cheese, mayonnaise, and bread, to solids, such as flour, powdered drink mixes, and potato chips. 

Angeletti, R. Gioacchini, A.M. Seraglia, R. Piro, R. Traldi, P. The Potential of MALDI-MS in die Quality Control of WatCT Buffalo Mozzarella Cheese. J. Mass Spectrom. 1998, 33, 525-531. 

Very low levels of biogenic amines occur in unripened cheese made from pasteurized milk, due to the pasteurization and the lack of a ripening period. Any high levels that may be found in unripened cheese would most likely be due to the use of poor-quality milk (Novella-Rodriguez et al., 2003). 

The concentration of biogenic amines in cheese could be used as an indicator for its freshness, and an indicator of the quality of the raw materials and manufacturing processes involved. 

Some of these government agencies and private companies, because of the nature of their business, will utilize the services of an analytical chemistry laboratory as part of their overall need to assure the required quality operation. For example, municipal governments will employ the use of an analytical chemistry laboratory to test their water supply on a regular basis to make sure it is free of toxic chemicals. The pharmaceutical company will house an analytical chemistry laboratory within its facility to routinely test the products it produces and the raw materials that go into these products to make certain that they meet the required specifications. A fertilizer plant will utilize an analytical chemistry laboratory to confirm that the composition of its product meets the specifications indicated on the individual bags of fertilizer. Companies that produce a food product, such as snack chips, cheese, cereal, or meat products, will have an analytical chemistry laboratory as part of their operation because they want to have the assurance that the... 

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