Y Ardo 1
During ripening, several biochemical processes 88 contribute to the development of typical structure and flavour of each Blue cheese variety. Some of the processes may produce pigment if the enzymes needed are present and the environment in the cheese stimulates its production. Brown spots in a Blue cheese are commonly of microbial origin and may be developed by contaminating yeasts or moulds. It may also be a result of highly active Penicillium roqueforti in long-ripened cheese, and...
What products may be produced from whey
For perhaps centuries, whey has been regarded as a problematic by-product of cheesemaking, and not an insubstantial one, with 90 of milk volume generally being released as whey. Options such as feeding to animals, dumping in waterways and spreading on land were practised until relatively recently in many countries, and may still be practised in certain regions. Recognition of problems such as the high biochemical oxygen demand of whey, rendering it a potent pollutant, and interest in recovery...
Starter preparation
Control of environmental conditions within the starter preparation area and application of aseptic methods are probably the most important considerations in the preparation of starter cultures for cheese manufacture. The starter room is a critical control point in ensuring that phage does not cause a problem in the subsequent transformation of milk into cheese. The starter preparation area should be located far away from cheese manufacture and subsequent whey handling facilities, and movement...
Introduction Din
The hardest cheeses are the Italian Grana varieties and their industrial counterpart, Parmesan. The hard grainy texture of Italian Grana-type cheeses e.g. Parmigiano-Reggiano or Grana Padano results from the use of raw semi-skimmed milk for their manufacture and a high cooking temperature -54 0C 36 and evaporation of moisture during their long ripening period often 2 years or more . Grana-type cheeses are sometimes consumed as a table cheese when they are young and relatively soft but the...
HE Spinnler and MN LeclercqPerlat Qyz
The 'toad-skin' and 'cat-hair' defects originate from uncontrolled development of fungi 134 . Specific strains of Geotrichum candidum are responsible for 'toad skin', which is characterised by a web of ridges at the cheese surface. This organism is able to produce arthrospores Fig. 1 which form chains. When these arthrospores are present at high density, the chains join together and are able to create ridges by pushing one against the other, causing the development of 'toad skin'. In some...
Introduction Cbr
A wide range of cheeses and cheese-like products are produced worldwide but from a very limited range of raw materials. Natural cheese is made from cow's, sheep's, goat's or buffalo's milk, lactic acid bacteria, rennet in the case of rennet-coagulated varieties and salt, yet it has been said that there is 'a cheese for every taste preference and a taste preference for every cheese'. Cheese has a long history and the collective heritage of certain varieties has been ensured in Europe by...
Ca2 concentration
A high Ca2 level in milk speeds up coagulation reduces RCT . The effect of Ca2 is mainly on the second stage of rennet coagulation, although it has a slight indirect effect on the first stage because addition of calcium to milk alters its salts balance 4 by causing a precipitation of colloidal calcium phosphate and the production of H , which reduces the pH. Calcium chloride CaCl2 is often added to cheesemilk to improve its coagulation properties 33 . Preheating e.g. pasteurisation, before it...
T P Guinee Tlh
Salt in cheese serves two major roles, namely it acts as a preservative 46 and contributes directly to flavour and quality Fig. 1 . The preservative action of NaCl is due to its depressing effect on the water activity aw of the cheese aw p po, where p and po are the vapour pressure of the water in a cheese and of pure water, respectively. Water not contributing to the vapour pressure of cheese may be considered as being held by the cheese matrix and not available for microbial growth. Moreover,...
Acidification
Cheeses are fermented dairy products and hence the controlled production of lactic acid from lactose by lactic acid bacteria LAB is an essential step during the manufacture of essentially all varieties. Milk for cheesemaking may be acidified by its indigenous LAB or by using a whey culture i.e. a volume of whey retained from a previous day's cheesemaking 18 . While these traditional techniques continue to be used for certain artisanal varieties, the use of selected cultures of LAB, known as...
Milk
Milk is a fluid secreted by the female of all mammals, the primary function of which is the complete nutrition of the neonate of the species. Since the nutritional requirements of the young of the different mammalian species differ greatly, it is unsurprising that the compositions of milks of different species vary considerably. Typical compositions of the milks of the principal dairy species are shown in Table 1. In addition to interspecies differences, milk from a particular species will also...
pH and organic acids
Most bacteria grow optimally at pH around neutrality and growth is often poor at pH values lt 5.0. Notable exceptions are lactobacilli, yeasts and mould, which grow well at pH 4.5. Owing to the fermentation process, organic acids accumulate in the cheese curd post-manufacture and the pH is decreased to between 4.5 and 5.3 these low pH values will not allow the survival of acid-sensitive organisms. The real inhibitor, however, is the undissociated form of the organic acid. The principal organic...
Standardisation and fortification of milk
Fat and protein levels in milk show seasonal variations. Standardisation of the casein to fat ratio 9 is undertaken to produce cheese of the required composition consistently through the year. The casein to fat ratio used is specific to a particular variety and is influenced by efficiency of fat and protein recovery in the manufacturing plant. Further advantage may be gained in terms of cheese yield and vat throughput by fortification of the protein content of milk. Spray dried milk protein...
M T FrohlichWyder and H P Bachmann Tbn
Irregular eye formation, slits and cracks are often a result of undesirable fermentations and or an inadequate body texture. The former include excessive propionic acid fermentation or its restart towards the end of ripening so-called 'late fermentation' and butyric acid fermentation 91 . A strong propionic acid fermentation is very often coupled with a strong aspartase activity of the propionibacteria 121 used together with a high availability of aspartate. Furthermore, excessive proteolysis...
HE Spinnler and MN LeclercqPerlat Wsv
Some yeasts, in starting to hydrolyse proteins and fat, will improve the nutrient content of the curd and thus help the growth of Penicillium camemberti. After 5-7 days of ripening, the growth of the mycelium of P. camemberti is observed and a white felt covers the entire surface of the cheese. The growth of P. camemberti is extremely fast compared with that of the other members of the ripening flora. In 23 days, its growth is complete and its metabolism changes the surface pH, exhausts lactate...
N M OBrien and T P OConnor
Biogenic amines are non-volatile, low molecular mass aliphatic, alicyclic or heterocyclic organic bases. Typically, they originate in foods from the decarboxylation of specific amino acids. Decarboxylation can occur due to indigenous decarboxylases in foods or to decarboxylases produced by microorganisms in the food. Biogenic amines are found in a variety of foodstuffs, most commonly fish of the families Scombridae and Scombereoscidae, but also in cheese. In cheese, biogenic amines are produced...
Yield losses postvat
Most of the losses in cheese manufacture occur in the cheese vat. About 6.5 of milk fat and 4-5 of the casein are lost during commercial Cheddar manufacture. The losses that occur post-vat are comparatively small approximately 2.0 of milk fat but are important determinants of cheesemaking efficiency. Following whey drainage the curd is subjected to a variety of handling procedures such as stirring, cheddaring 101 , milling, salting 39 and prepressing. During these operations, moisture and fat...
How should cheese brine be prepared and maintained
Brine should be prepared by dissolving at room temperature the appropriate quantities of sodium chloride and calcium chloride in reverse-osmosis treated water that has ideally been pasteurised or sterilised by UV radiation. The final levels of NaCl and Ca in the brine should typically be -22 w w and -0.3 to 0.5 w w , respectively, even though the exact calcium level will depend on the level in the cheese. Dissolution of the NaCl is aided by constant recirculation of the brine. The pH of the...
Ripening temperature
Temperature is one of the few parameters the cheesemaker can manipulate to control microbial development during the ripening stage of cheese production. The microorganisms involved in cheese manufacture and ripening are either mesophilic or thermophilic, having temperature optima between 30 and 42 0C. The temperature at which cheese is ripened is a compromise between the need to promote ripening reactions and control growth of the desirable secondary flora, and the need to prevent the...
Further reading Hty
BERESFORD, T.P. and WILLIAMS, A. 2004 . The microbiology of cheese ripening, in Cheese Chemistry, Physics and Microbiology Volume 1 General Aspects, 3rd edn., P.F. Fox, P.L.H. McSweeney, T.M. Cogan and T.P. Guinee eds. , Elsevier Academic Press, Amsterdam, pp. 287-317. GUINEE, T.P. and FOX, P.F. 2004 . Salt in cheese, in Cheese Chemistry, Physics and Microbiology Volume 1 General Aspects, 3rd edn, P.F. Fox, P.L.H. McSweeney, T.M. Cogan and T.P. Guinee eds. , Elsevier Academic Press, Amsterdam,...
Introduction 1
Cheese is analysed for a wide range of reasons including to ascertain its composition as part of a quality control system or to generate data for nutritional labelling 69, 70, 72 , to ensure compliance with standards of identity of a particular variety, to assess the efficiency of production and to ensure the microbial safety of the product 58, 59 . Before analysis, cheese must be sampled properly, as the reliability of the results of any analytical procedure is dependent on how representative...
Bibliography
General reference texts on dairy chemistry FOX, P.F. ed. 1997 . Advanced Dairy Chemistry - 3. Lactose, Water, Salts and Vitamins, 2nd edn, Chapman and Hall, London. FOX, p.F. and McSWEENEY, P.L.H. 1998 . Dairy Chemistry and Biochemistry. Blackie Academic and Professional Publishers, London. Reprinted with corrections, Kluwer Academic Plenum Publishers, New York, 2003. FOX, P.F. and McSWEENEY, P.L.H. eds. 2003 . Advanced Dairy Chemistry - 1. Proteins, 3rd edn, Kluwer Academic Plenum Publishers,...
P L H McSweeney Skl
The composition of milk affects syneresis but the effect is usually not large. Increasing the fat content of the milk slows syneresis somewhat and increases the water-holding capacity of cheese curd. Fat globules act as obstacles for the outward movement of moisture from the curd and for this reason increasing the fat content of milk increases cheese yield 48 absolute yield, Ya by about 1.2 times the mass of added fat. The effect of the casein level in milk on syneresis is not entirely clear,...
Introduction Hir
Hard cheeses are ripened after manufacture for periods ranging from a few months to 2 or more years and it is during this ripening period that the flavour and texture characteristic of the variety develop 54, 88 . Cheese ripening usually involves changes to the microflora of the cheese 54, 56 , often death and lysis of starter cells, the development of an adventitious non-starter microflora 56 and, in certain cases, the growth of secondary organisms 117, 128, 137, 142 . It is often difficult to...
Further reading Fzd
BERESFORD, T.P, FITZSIMONS, N.A., BRENNAN, N.L. and COGAN, T.M. 2001 . Recent advances in cheese microbiology. Int. Dairy J. 11, 259-274. BERESFORD, T. and WILLIAMS, A. 2004 . The microbiology of cheese ripening, in Cheese Chemistry, Physics and Microbiology Volume 1, P.F. Fox, P.L.H. McSweeney, T.M. Cogan and T.P. Guinee eds. , Elsevier Academic Press, Amsterdam, pp. 286-317. COGAN, T.M. and BERESFORD, T.P. 2002 . Microbiology of hard cheese, in Dairy Microbiology Handbook, the Microbiology of...
Further reading Prw
CRABBE, M.J.C. 2004 . Rennets general and molecular aspects, in Cheese Chemistry, Physics and Microbiology Volume 1 General Aspects, 3rd edn, P.F. Fox, P.L.H. McSweeney, T.M. Cogan and T.P Guinee eds. , Elsevier Academic Press, Amsterdam, pp. 19-43. FOX, P.F., GUINEE, T.P., COGAN, T.M. and McSweeney, P.L.H. 2000 . Fundamentals of Cheese Science, Aspen, Gaithersburg, MD. GUINEE, T.P., O'KENNEDY, B.T. and KELLY, P.M. 2006 . Effect of milk protein standardization using different methods on the...
What causes the development of gas during ripening
Development of gas in cheese during ripening is evident by the occurrence of eyes, cracks, slits, fissures, holes or gas within the packaging. Gas produced during cheese ripening may occur within the first few days of ripening early gas or towards the latter stages of ripening late gas . Gas creating numerous small holes and produced in cheeses shortly after manufacture is usually caused by the growth of coliform bacteria or yeasts. This defect is more common in soft and semi-soft cheeses...
Late gas in Cheddartype cheese
Gas production during ripening and openness in Cheddar-type cheeses 100 may be due to contamination of milk by heterofermentative organisms such as lactobacilli. Non-starter lactic acid bacteria NSLAB 56 grow during ripening and heterofermentative lactobacilli such as Lactobacillus brevis and Lactobacillus fermentum are able to produce gas in Cheddar cheese. Gas production occurs from the fermentation of residual lactose and galactose to C02. Salt-in-moisture S M levels influence starter...
P L H McSweeney Psk
The Phe105-Met106 bond of K-casein is many times more sensitive to rennet action 24 than any other bond in the caseins. However, the Phe-Met residues are not essential human, porcine and rodent K-caseins have Ile or Leu at position 106 and, interestingly, the proteinase of Cryphonectria parasitica 29 cleaves the adjacent bond Ser104-Phe105 . The importance of the Phe-Met bond has been investigated by studying the action of chymosin 27 on short peptides with the same amino acid sequence as this...
Contributor contact details
Editor and questions 1, 6, 11, 12, 14, 17, 20, 22-30, 34-36, 38, 54, 58, 69, 72, 76-78, 81, 83-84, 87-91, 96, 100, 105, 107, 141, 187-188, 197 Professor P. L. H. McSweeney Department of Food and Nutritional Sciences University College Cork Cork Ireland Aristotle University of Thessaloniki Professor Y. Ard Department of Food Science Faculty of Life Sciences University of Copenhagen Rolighedsvej 30 1958 Frederiksberg C Denmark Questions 16, 48-52, 79, 80, 85, 92-95, 101-104 Dr J. M. Banks NIZO...
Photooxidation Of Norbixin
Cheddar is a hard cheese that originated from the village of the same name in the south-west of Britain and is now among the most important cheeses made worldwide, particularly in English-speaking countries. Cheddar cheese is made from pasteurised 10, 11 , standardised 9 cow's milk Fig. 1 . Mesophilic starter cultures 18 are used and, in large cheese factories, defined-strain starter systems are common. The milk is renneted at -30 0C and the curds whey mixture is cooked to 37-390C. After whey...
Why is CaCl2 often added to cheesemilk
The addition of CaCl2 at levels of -0.2 g l, i.e. -1.8 mM Ca, to milk is common commercial practice, especially if the cheesemilk displays poor rennet coagulation and curd forming characteristics. Poor rennet coagulability of milk 30 can be the result of a variety of factors such as low protein level in milk, late lactation milk 3 , high pH e.g. gt 6.7 , prolonged holding of milk at low temperature prior to cheese manufacture, high somatic cell count 8 , high enzymatic activity or elevated...
Do pathogens grow during cheese ripening
Whether pathogens grow or decline during ripening depends largely on the chemical and compositional properties of the cheese variety in question. In general, cheeses with high moisture contents, or those with a neutral pH due to bloomy rind or smear development, will support the survival or growth of pathogens during ripening. Conversely, in hard, low-moisture cheeses with a low pH, pathogens die during ripening. Pathogens can be present in cheeses either as a result of surviving pasteurisation...
What factors should be considered to reduce coliform counts
Coliforms refer to a broad group of aerobic and facultatively anaerobic, Gramnegative, non-sporeforming, rod-shaped bacteria that ferment lactose. Coliform bacteria of significance in cheeses include the non-enteric genera Serratia and Aeromonas, along with Citrobacter, Klebsiella, Escherichia and Enterobacter. Some coliforms are indicators of faecal contamination and if counts are high, they can indicate the potential presence of bacterial pathogens 58 . Methods for detection of coliforms in...
Milk handling and cold storage
A cheese factory operating to capacity may have to store milk cold for a period of 1-3 days prior to manufacture. Prior to arrival at the creamery, the milk may have been cold stored on the farm for up to 3 days and then transported substantial distances from farm to creamery. During storage and transport the temperature will be below 60C, and the milk will be subjected to shear through pumping and agitation. Cold storage and shearing encourage a number of physicochemical changes in the milk...
Oxidationreduction potential h
The oxidation-reduction redox potential Eh is a measure of the ability of a chemical biochemical system to lose oxidation or gain reduction electrons. An oxidised or reduced state is indicated by a positive or negative redox potential respectively. The Eh of milk is about 150 mV, while that of cheese is about 250 mV. While the mechanism of Eh reduction in cheese is not fully established, it is most probably related to fermentation of lactic acid by the starter during growth, and the reduction...
What cheeses are most liable to pathogens
The characteristics of the specific cheese variety dictate the potential for growth and survival of microbial pathogens. In general, ripened soft cheeses present a higher risk for growth and survival of pathogens in comparison with aged hard cheeses 83 where a combination of factors including pH, salt content and water activity aw interact to render cheeses microbiologically safe. Many hard cheeses aged for 60 days or more are made from raw milk e.g. Parmigiano Reggiano, Grana Padano 96 ,...
Starter selection
Starter cultures can be divided into two primary types, mixed-strain and defined-strain starters 18 . Mixed-strain cultures contain an undefined mix of species and strains of bacteria. It is estimated that approximately 90 of the bacteria in the culture contribute to acid production while the remaining 10 are predominantly involved in the production of flavour compounds. Such cultures have a long history of successful use in industry and examples of their use in large-scale manufacture of...