Izabela Steinka

Chemical Correlations Between Industrial Curds and Final Cheeses. Can Cheesemakers Standardise Productions

The chemical composition of milks and curds influences the microbial ecology and chemical features of produced cheeses. This statement is quite obvious because ‘normal’ cheeses—products with a prevailing ingredient, milk—are obtained by means of the transformation of the main raw material and the addition of minor components. Because of the possible scarcity of readily available milk in many regions or economic areas, the industry of milk and dairy products, including cheeses, has improved the production of ready-to-use curds. These products, also named ‘industrial curds’, are produced exclusively for further cheesemaking processes. For this reason, ready-to-use curds are pre-packaged with the aim of supplying cheesemaking industries. However, the standardisation of curds is easily possible only near curd-making industries. This Chapter discusses adequate countermeasures for final cheesemakers; on the other side, the complete control on cheese production parameters in these conditions does not seem to be a possibility at present.

Technology and Chemical Features of Frozen Vegetables

The aim of this study has been the description of the current state of the art of frozen vegetables. One of the most promising food and beverage categories in the current market is represented by frozen products, although the modern food industry is officially born in 1928 in the United States of America. Before this date, previous freezing systems were based on the production of ice, with the use of refrigerating machines and the development of storage rooms. At present, the evolution of this sector can be briefly identified with the improvement of freezing techniques, the notable demand of food supplies worldwide, and the increasing number of frozen food typologies, including fruits and vegetables. Basically, frozen foods are very similar to original products when speaking of sensorial features. On the other side, some defects have been observed and correlated with freezing techniques and blanching treatments. The most used systems—air blast, plate and immersion freezers—are discussed with the description of correlated advantages and risks, including economic evaluations.

Colorimetric Modifications in Frozen Vegetables

The success of frozen foods in the current market is linked to the virtual absence of sensorial modifications, although irreversible textural modifications and general damages to plant tissues after defrosting are reported when speaking of vegetables. In addition, flavour changes and discoloration have been reported. Reasons may be different and possibly linked to blanching treatment and storage, while freezing techniques could be not so important. With exclusive relation to colorimetric changes, the main cause is reported to be the residual activity of enzymes such as lipoxygenase and peroxidase. For these reasons, the limitation of available oxygen during freezing is a good strategy. The so-called ‘freezer burn’ is also considered as a probable cause. In addition, physical browning may occur after mechanical manipulation and correlated stress, as stated by Parisi in his second Law of Food Degradation. The analytical evaluation of colour modification may be carried out by means of CIE lab-based colorimetric systems, or ‘digital image analysis and processing’ techniques. Moreover, enzymatic browning may be evaluated spectrophotometrically. The diminution of light-sensible vitamin C can be also considered. Finally, food industries are accustomed to use simplified food pictures or colorimetric charts with the aim of simplifying inner quality controls.

Evolutive Profiles of Caseins and Degraded Proteins in Industrial Cow’s Milk Curds

The importance of prepackaged curds in the current cheese market is increased in the last years because of the persistence of cyclic periods with remarkable diminution of stored raw materials. Consequently, the cyclic deficiency of cow’s milk may determine the subsequent lack of correlated derivatives and force manufacturers to use prepackaged curds. Because of the critical importance of the chemical and microbiological ‘quality’ of these curds, the study of evolutive profiles of casein contents in selected industrial curds should be recommended. The aim of this chapter has been to show the analytical results of an industrial study carried out on seven different cow’s milk curds during storage. Obtained data and calculated results seem to suggest that curd samples under refrigerated conditions can show increased proteolysis. In addition, moisture and pH values may show notable augments during refrigerated storage. On the other side, deep-frozen storage is recommended when speaking of curd use after extended storage times.

The Chemistry of Frozen Vegetables

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Antibiotic-Resistant Staphylococci Isolated from Hermetically Packaged Frozen Vegetables

price are net prices, subject to local VAT. Prices indicated with * include VAT for books; the €(D) includes 7% for Germany, the €(A) includes 10% for Austria. Prices indicated with ** include VAT for electronic products; 19% for Germany, 20% for Austria. All prices exclusive of carriage charges. Prices and other details are subject to change without notice. All errors and omissions excepted. I. Steinka, C. Barone, S. Parisi, M. Micali The Chemistry of Frozen Vegetables

Instrumental Systems for the Control of Frozen Vegetables During Refrigeration

The aim of this study was to evaluate the prevalence of antibiotic-resistant staphylococci in frozen vegetables during long-term storage of these products. The vegetables were subjected to freezing at −40 °C (fluidisation technique). Experimental temperature values in frozen tissues reached −18 °C. Vegetables were packed in polyethylene airtight bags. The study involved 33 assortments of frozen vegetables. The number of Staphylococcus aureus in frozen vegetables achieved 3.5 log10 CFU/g; 4.7% of these samples showed unacceptable microbial counts. The maximum level of methicillin-resistant S. aureus was 4.25 log10 CFU/g. All samples showed also the presence of aerobic bacteria without correlation between their number and staphylococci counts. On these bases, the Regulation (EC) No. 2073/2005, recently amended in 2007, could be modified with a condition concerning the absence of S. aureus in vegetable products ready for frozen storage because of the possible detection or the presence of methicillin-resistant S. aureus in final products.

Chemical Profiles of Industrial Cow’s Milk Curds

The aim of this study has been the description of storage technologies used at present for frozen foods. The necessity of long-durability foods seems one of the main distinctive features of the globalised market. In addition, the perishability of certain food commodities has to be considered as a first-level pillar of the modern food science and technology. There are not foods or beverages which could remain unmodified during time, on the basis of Parisi’s Law of Food Degradation. A reliable freezing process is only the first step in the entire preservation flow chart with the exclusion of initial production steps; in fact, the most important result is the final performance of deep-frozen products until the desired or planned expiration date. For this reason, frozen foods have to remain continually exposed to low temperatures (≤−18 °C). This condition is the so-called ‘cooling chain’ and concerns logistic operators into and outside food companies until the final use. The current availability of system controls after freezing and packaging steps—freezer warehouses, rooms, chillers and household freezers—is notable enough in the current market of industrial equipments. Each of these systems is described here with correlated advantages and cost evaluations.

Optimising Lactic Acid Cheese Packaging Systems

On the basis of a previous research, it seems that foil-wrapped tray solutions are not particularly chosen by lactic acid cheese consumers. With relation to this study, almost half of the respondent population would have expressed the desire of different packages. Parchment packages and poly(ethylene-co-vinyl acetate)/polyvinylidene chloride/poly(ethylene-co-vinyl acetate) laminates would be removed by 25.0 and 12.5% of customers, respectively. Polyamide/polyethylene double and single packaging would be removed from the market only by 5.0% of respondents. Data have shown that cheese and packaging quality are dependent on lactic acid cheese surface microflora. The type of this microflora is particularly dependent on packaging air-tightness. Anaerobe microorganisms and their metabolites influence properties of packaging materials. On these bases, and considering customers’ requirements, a modified packaging system was elaborated. One strategy for optimising traditional packaging systems is the aloe incorporation into the packaging design. The proposed modification of cheese packaging system would include the coating of packaging surfaces (made of synthetic materials) with a thin layer of aloe aerosol and an edible layer, decomposed by lactic fermentation bacteria after a given period of cheese storage. C. Barone (&) Associazione “Componiamo il Futuro” (COIF) Palermo, Palermo, Italy e-mail: fct1970@libero.it M. Barbera DEMETRA Department, University of Palermo, Palermo, Italy e-mail: marcellapu@hotmail.it M. Barone Associazione “Componiamo il Futuro” (COIF) Palermo, Palermo, Italy e-mail: fct1970@libero.it S. Parisi Industrial Consultant, FSPCA PCQI, Palermo, Italy e-mail: drparisi@inwind.it I. Steinka Gdynia Maritime University, Gdynia, Poland e-mail: ize13ste@wp.pl

The Production of Industrial Cow’s Milk Curds

On the basis of a previous research, it seems that foil-wrapped tray solutions are not particularly chosen by lactic acid cheese consumers. With relation to this study, almost half of the respondent population would have expressed the desire of different packages. Parchment packages and poly(ethylene-co-vinyl acetate)/polyvinylidene chloride/poly(ethylene-co-vinyl acetate) laminates would be removed by 25.0 and 12.5% of customers, respectively. Polyamide/polyethylene double and single packaging would be removed from the market only by 5.0% of respondents. Data have shown that cheese and packaging quality are dependent on lactic acid cheese surface microflora. The type of this microflora is particularly dependent on packaging air-tightness. Anaerobe microorganisms and their metabolites influence properties of packaging materials. On these bases, and considering customers’ requirements, a modified packaging system was elaborated. One strategy for optimising traditional packaging systems is the aloe incorporation into the packaging design. The proposed modification of cheese packaging system would include the coating of packaging surfaces (made of synthetic materials) with a thin layer of aloe aerosol and an edible layer, decomposed by lactic fermentation bacteria after a given period of cheese storage.