The key innovation that was to define the commodity cheesemaking industry for decades, not only in New Zealand but also world-wide, occurred from 1960 onwards, when the essentially manual cheesemaking industry was mechanised and automated. Driven by the need to reduce cost, increase scale and reduce labour inputs and the need for greater product uniformity and consistency, the cheesemaking process underwent significant changes with respect to the equipment and processes used. Those changes maximised milk processing capacity and minimised labour input while maintaining, and in many cases enhancing, product quality. As a consequence of this revolutionary approach to cheesemaking, cheese plants in New Zealand became larger and fewer, and the companies that operated them amalgamated.Although the past 40 years have not seen the same magnitude of change in technology that defined the mechanisation of the cheesemaking process in the decade preceding 1970, continued innovation has seen significant refinements in the way in which cheese is made by the mechanised process that have led to further reductions in cost, increased scale efficiencies, greater product uniformity and consistency and fewer labour units being required. Recent published literature and patent applications would suggest that the next innovative steps in the evolution of cheesemaking in the 21st Century will be the development of new ways of making cheese together with the continued refinement of the traditional processes that we have seen to date.As an example, in February 2008, the New Zealand dairy industry commercialised an innovative mozzarella process that is an alternative approach to traditional mozzarella manufacture. Unique to New Zealand, this process produces a functionally acceptable product in a shredded format directly off the line in less time than the traditional process. Aust. J. Dairy Technol. 65, 122-127
An effective process for reducing milk cholesterol by enzymatic treatment was investigated in this study. Cholesterol oxidase from Nocardia erythropolis was used for this purpose. The target of this investigation was to obtain the optimum operational conditions for bioconversion of milk cholesterol by cholesterol oxidase (COD). The bioconversion process was investigated first, to obtain basic information about the process, and was further optimised by analysing the parameters, including temperature, pH, incubation time and enzyme content, by using the Taguchi Approach, which is a statistical method for optimisation. Also the direct effect of each parameter on cholesterol bioconversion rate has been studied. As a result, the suitable operational conditions were obtained: temperature 32 C, pH 7.5, incubation time of 120 min and enzyme content in milk 0.15 U/mL, which under these conditions, approximately 70% of milk cholesterol was removed. Aust. J. Dairy Technol. 65, 10-14
Adjunct cultures increase the intensity, and change the balance of cheese flavour, mainly in hard and semi-hard varieties. They are purpose-made cultures added deliberately by the cheesemaker, over and above the normal culture usage, to achieve flavour enhancement and/or modification. Most flavour adjuncts are lactic acid bacteria (LAB) derived from existing cheese starter lactic acid bacteria (SLAB), or the natural adventitious secondary non-starter lactic acid bacteria (NSLAB). SLAB-based adjuncts, developed from good flavour-producing starters, are effective in flavour enhancement, but require attenuation of acid production and concentration to high biomass before inclusion in cheesemaking recipes. NSLAB-based adjuncts are easier to use, not requiring any modification before use in cheesemaking, but can produce flavour and texture defects. Cheese smear bacteria, yeasts and moulds might be adapted as flavour adjunct, but they remain essentially experimental at this stage. Exopolysaccharide-producing LAB are under active trial, particularly in low fat cheese technology, to compensate for their poor texture and water phase control. Probiotic health 'functional' adjuncts are also in the pipeline.
This review addresses the importance of effective cleaning and sanitation programs in assuring food safety and dairy product quality. The processes of organic fouling and biofilm fouling have a major impact on cleaning efficiencies and methods and have a significant impact on operational efficiencies. The challenge for the dairy industry is to improve cleaning performance against biofilm matrices and achieve complete disinfection, extending the time for re-colonisation of new biofilms and increasing production run lengths. The fundamental requirements for effective cleaning remain constant and limitations cannot be compensated for through chemistry solutions. Traditional cleaning chemistries have improved only incrementally in the last 60 years, but very recent developments using oxidative precursor programs offer significant cleaning performance enhancement whilst addressing key sustainability performance indicators and operational gains. The use of latest generation biocides in association with these chemistries offers the prospect of genuine biofilm disinfection. Alternative methods for biofilm disruption including surface modification, phage disruption and temperature cycling offer future prospect although none are yet ready for commercial adoption.
Non-thermal treatments and the use of natural antimicrobial compounds, whether deliberately added (ex situ) or produced in situ by food bacteria, are of considerable interest to the dairy industry. Foodgrade lactic acid bacteria (LAB), the majority of starter cultures applied in the dairy industry, possess an enormous antimicrobial potential. Bacteriocins, which are antibacterial peptides, are produced by all LAB species. Due to their antagonistic activities, bacteriocins can be used as non-thermal means to prevent spoilage, technical defects or safety problems in cheese, and to promote cheese quality. In the present review paper, a state-of-the-art is given of the best-studied bacteriocins that may help to combat undesirable bacteria in dairy applications, i.e. nisins, lacticins, macedocin and a range of non-lantibiotic bacteriocins, in particular enterocins. Although bacteriocins and bacteriocin-producing starter or adjunct cultures are already applied industrially by cheese manufacturers, several drawbacks hinder wider applications. Aust. J. Dairy Technol. 65, 143-149
Fermentation-produced camel chymosin (CC) has been shown to produce full-fat cheddar cheese with good flavour and reduced bitterness. We investigated the use of CC on the-flavour and texture of low-fat cheddar cheese. Cheeses were manufactured from skim milk (0.5% fat, casein:fat 5.1). Lactococcus lactis subsp. lactis blend that was known to produce bitterness in cheddar cheese was used as the starter culture. Calf chymosin and CC were added at levels of 7.7 and 3.9 mL/100 kg milk, respectively. Cheese functionality was assessed using the UW-Meltprofiler, texture profile analysis (TPA) and dynamic low-amplitude oscillatory rheology. A trained sensory panel evaluated the cheeses for textural and flavour attributes. There were no significant differences (p>0.05) in the composition and pH between the cheeses. TPA hardness and chewiness decreased during ripening and both parameters were significantly higher (p<0.05) in cheeses made with CC. During ripening, the maximum loss tangent (LTmax) values (meltability index from rheology tests) were always significantly lower in cheeses made with CC. Temperature of LTmax was similar in all cheeses but decreased with age. Degree of flow was also lower in the cheeses made with CC compared to those made with calf chymosin. Descriptive sensory analysis indicated that the cheeses manufactured with CC had lower bitterness than those made with calf chymosin. Sensory texture analyses demonstrated that cheeses manufactured with calf chymosin were softer and less chewy than those made with CC. In low-fat cheddar cheese made with cultures prone to produce bitterness, the use of CC resulted in lower bitterness compared to cheese made with calf chymosin but CC use did not entirely eliminate bitterness. Aust. J. Dairy Technol. 65, 139-142
In order to determine the effect feeding differences on natural antioxidant vitamin delivery, two contrasting diets, lucerne (ALF) and sorghum silage (SS), were analysed. Diets showed different profiles for fat-soluble vitamins. ALF was higher in a-tocopherol, beta-carotene and retinol than the SS diet. On the contrary, SS diet was higher in gamma- and delta- tocopherol, due to the soy expeller contribution in these isomers. The ALF diet favoured higher milk production and protein yield in comparison to SS, whereas the fat content was the opposite (p<0.01). The composition of the diets was partially reflected in milk. The ALF diet favoured the incorporation of alpha-tocopherol, retinol, beta-carotene and vitamin D-3 into raw milk. Meanwhile, a less abundant isomer of vitamin E, gamma-tocopherol, was significantly higher in the SS than the ALE milk and delta-tocopherol was not detected. In addition, the ALF diet also promoted higher antioxidant activity. The ferric reduction antioxidant power (FRAP) was significantly higher in ALE than in SS milk, however oxidation determined by thiobarbituric acid reactive substances (TBARS) was similar for both types of milk. Also, no differences in ascorbic acid concentration were detected in either type of milk. The ALE and SS milks were clearly separated (100%) by their antioxidant status and odour profiles as a function of feeding into SS and ALE groups when the biochemical variables and sensor LY2/gCTI were analysed together. Two linear Fischer's discriminant functions were defined according to dietary treatments using beta-carotene and sensor LY2/gCTI. The success rate of correct classification of each sample was 100%, either for the original cases or after cross-validation (p<0.0001). The use of an electronic nose proved to be a useful instrumental method to discriminate the odour profile of milk samples with a different antioxidant status. Aust. J. Dairy Technol. 65, 3-9
Factors associated with split and secondary fermentation defects in Swiss-type cheeses include seasonality of milk supply, interactions between lactic and propionic acid bacteria and variability in cheese composition. Swiss-type cheeses produced from a seasonal milk supply were sampled on two days per month of the production year (season), at three different times during the manufacturing day (time of day), at internal and external regions of the cheese block (area) and at four ripening time points (ripening: d 7, post hot room, d 14 post hot room and 3 months in a cold room). Compositional, biochemical and microbial indices were determined, and the results were analysed as a split-plot with a factorial arrangement of treatments (season, time of day, area) on the main plot and ripening time on the sub-plot. Cheese salt levels were not equilibrated within the 60 kg cheese block 3 months post exit from hot room. Season (and interactions) had a significant effect on pH and salt-in-moisture levels (p<0.01), on mean counts of L. helveticus, propionic acid (p<0.05) and non-starter lactic acid bacteria (p<0.001), on levels of primary and secondary proteolysis (p<0.01; as measured by nitrogen soluble at pH 4.6 and in 5% phosphotungstic acid) and on cheese firmness. Levels of proteolysis increased significantly during hot room ripening but also during cool room storage. Rheological parameters (e.g. springiness and cohesiveness) were significantly affected by interactions between ripening and sampling area within cheese blocks. Trends identified will enable seasonal manipulation of manufacture protocols to minimise compositional and biochemical variability and to reduce the occurrence of split and secondary fermentation defects.
Milk processing prior to cheesemaking serves a number of functions, but may also irreversibly change the structure of the milk components. The effect of processing parameters on the microstructure of several milk preparations was assessed using transmission electron microscopy (TEM). Our TEM results confirmed the presence of the native milkfat globule membrane on fat globules within raw milk, within raw milk ultrafiltration retentate and within pasteurised and standardised milk for cheddar cheesemaking. Sodium dodecyl sulphate - polyacrylamide gel electrophoresis confirmed the identity of the native MFGM proteins isolated from the surface of fat globules. In contrast, homogenisation produced the greatest changes in the microstructure of the fat globules, where the native MFGM could not be detected using TEM. The fat globules within homogenised milk had mostly casein present on the fat globule surface. These changes in the microstructure of the milk components may alter the microstructure of downstream products. Our results highlight the potential use of TEM to complement previously reported techniques such as confocal laser scanning microscopy (CLSM) to provide valuable information about membrane integrity and changes associated with milk preparation for cheddar cheese production. Aust. J. Dairy Technol. 65, 222-225
Pathogenic E. coli cause gastrointestinal illness in humans with the most severe cases resulting in long term sequelae or death. Clinical disease results from ingestion of pathogenic E. coli following contact with infected humans or animals or via the consumption of contaminated water or food. Many types of pathogenic E. coli can be found in animals including cattle, sheep, buffalo and goats, and wildlife. E. coli are shed in animal faeces which can contaminate primary produce. A range of dairy products have been implicated in E. coli illness including milk, cheese, yogurt and ice- cream. Outbreaks have frequently been attributed to raw or unpasteurised dairy products, although products inadequately processed and contaminated post-processing have also been implicated. Pathogenic E. coli are carried in healthy animals raised on dairy farms in Australia and are important hazards in the food safety risk profile for the dairy industry. In the few outbreaks of disease caused by pathogenic E. coli reported in Australia, dairy products have not been implicated, highlighting effective risk management for this hazard in local dairy products. The safety of dairy products will be ensured by continued awareness of the hazards and management of the food safety risks through the dairy product supply chain from farm to consumer.
Non-starter adventitious lactobacilli grow in cheese, reaching elevated numbers during late ripening. The interest may concern the use of non-starter lactobacilli as an adjunct in the form of fresh or attenuated cells. The use of adjunct starters may have several repercussions for flavour and acceleration of the maturation, depending on microbial species/strains and/or the cheese varieties. Caciotta is a traditional cows' milk cheese manufactured in Italy. Usually, ripening of this variety is not extended to more than three months. This work aimed to study the effect of selected non-starter lactobacilli adjuncts, in the form of fresh or attenuated cells, on the ripening of caciotta cheese. In a preliminary study, 60 strains of mesophilic lactic acid bacteria were screened based on the following enzyme activities: aminopeptidase type N, proline iminopeptidase, endopeptidase, glutamate dehydrogenase, and cystathionine lyase. Lactobacillus easel LC01, Lactobacillus curvatus 2770 and Lactobacillus paracasei FC25 were selected and used as adjuncts, in form of fresh or attenuated cells for making caciotta cheese at an industrial plant. The control cheese was manufactured under the same conditions, except for the adjunct. Cheeses were analysed during the ripening (60 days) for chemical and microbiological composition. Random Amplified Polymorphic DNA-Polymerase Chain Reaction (RAPD-PCR) analysis was used to monitor the population of non-starter lactobacilli during caciotta cheese ripening. Proteolysis was evaluated by the determination of total and individual concentration of free amino acids and by urea-PAGE and RP-FPLC analyses of water-soluble and insoluble fractions. Enzyme activities were determined in the water extract of the cheeses. Aust. J. Dairy Technol. 65, 189-191
There is a long tradition of artisanal cheesemaking in Portugal. A number of cheese varieties are indeed manufactured locally from raw ewes' or goats' milk (or a mixture of both) at the farmhouse level, which are traded chiefly within their production area. Despite the current dominance of industrial cheeses on the world market obtained from pasteurised cows' milk, farmhouse ewes' and goats' milk cheeses still have an important market niche in that country, and are in increasingly higher demand owing to their organoleptic uniqueness. The most outstanding Appellation d'Origine Protegee (AOP) cheeses are Azeitao, Castelo Branco, Evora, Nisa, Serpa and Serra da Estrela, for which the milk is clotted with a plant coagulant without deliberate addition of any starter or non-starter culture. The aforementioned coagulant is a crude aqueous extract from the flowers of Cynara cardunculus (cardoon) - a kind of thistle related to the globe artichoke, which can be found in dry, stony areas in Southern Portugal. Its (aspartic) proteinases possess an unusually wide specificity towards cleavage of peptide bonds; their activity spectra account for an extensive primary proteolysis of caseins to medium- and small-sized peptides. On the other hand, the adventitious microflora entail several lactic acid bacteria, e.g. Leuconostoc lactis and L. mesenteroides ssp. dextranicum, Lactobacillus paracasei ssp. paracasei, Lactococcus lactis ssp. lactis and Enterococcus faecium; their contribution to flavour development throughout ripening is crucial, especially owing to secondary proteolysis followed by amino acid catabolism toward small volatile molecules with a very low odour threshold.
This paper investigates two of the most commonly used end product microbial indicator tests, Standard Plate Count and coliforms, that are used by the dairy industry in Australia. The use of these particular tests, as a component of dairy manufacturers' food safety programs, is discussed. Their use as a tool to benchmark industry performance through an industry-wide Product Testing Program in the state of Victoria is also described, and the benefits derived from the program explored.
The main causes of cardiovascular diseases are obesity and hypertension, both of which are associated with high fat intake and high fat and sodium intake, respectively. Requeijao cremoso - a type of processed cheese that is an important part of the eating habits of average Brazilians - is a source of fat and salt (sodium chloride), as are most cheeses. In view of the high consumption of this cheese in Brazil, and the current demand for healthier foods, no-fat added reduced-sodium requeijao (NFARSR) would be an alternative to meet the needs of the changing market. The objective of this study was to optimise the use of emulsifying salts (JohaS9+JohaB50) so as to reduce the level of sodium of an existing no-fat added requeijao formulation developed earlier at the Instituto de Tecnologia de Alimentos-ITAL. In this study, the fat in requeijao was replaced by whey protein concentrate (WPC34), and sodium reduction was achieved by partially (40%) substituting potassium chloride for sodium chloride and by replacing part of the traditional sodium phosphate-based emulsifying salt (JohaS9) by a sodium-and-potassium-based emulsifying salt (JohaB50) containing 85% less sodium compared to S9. To this purpose, a 22 factorial design with two factors (JohaS9 and JohaB50) and two levels (+1, -1) was used, resulting in 11 experimental trials. The results were evaluated by response surface methodology to assess physical-chemical, sensory and instrumental texture parameters. Analysis of the response surface graphs showed that R5 - made with 1.0% JohaS9 and 1.2% JohaB50 - was the NFARSR formulation that best met the pre-set specifications. Aust. J. Dairy Technol. 65, 217-221
Modern cheesemakers seek much the same result as their ancestors: a predictable, consistent product that is safe to eat, tastes good, keeps well and is not too expensive to make. The difference is 8,000 years of technological development and just over a century of microbiological science. This paper reviews some of the fundamentals of starter cultures and their application, with reference to present practices and issues facing starter producers and users.
In the present study, 26 traditional cheeses manufactured with raw or pasteurised milk in the Marche region (central Italy) were characterised on the basis of gross composition, bacterial ecology and volatile compound profile. The cheeses under study were made from goats' milk (caprino), ewes' milk (pecorino) or a mixture of cows' and ewes' milk (caciotta). Data obtained were subjected to Principal Component Analysis (PCA) and Partial Least Square Discriminant Analysis (PLS-DA) in order to assess the relationships between cheesemaking techniques and physico-chemical, microbiological and aromatic traits. A clear separation between the three types of cheese was seen, whereas no distinction between raw and pasteurised milk cheeses was highlighted. Eight selected cheeses were subjected to a consumer test to evaluate the acceptance of potential purchasers. Aust. J. Dairy Technol. 65, 135-138
Flavour development in dairy fermentations, most notably cheeses, results from a series of (bio)chemical processes in which lactic acid bacteria (LAB) play a pivotal role. Flavour compounds in cheese arise from the action of added enzymes such as rennet, indigenous milk enzymes, enzymes originating from added primary and secondary (adjunct) starter organisms and the nonstarter bacteria (so-called NSLAB). Studies on flavour compound formation by LAB have shown that three main processes can be distinguished: conversion of lactose and citrate (carbohydrate metabolism); degradation of fat (lipolysis); and degradation of caseins (proteolysis). The diversity of cheeses in the market requires a diversity of commercial starter cultures, including the use of different species as adjunct cultures that are selected based on their flavour-related properties. In addition, specifically selected adjuncts are helpful for modulating the cheese texture, i.e. the exopolysaccharide producers. This paper will review the opportunities offered by the adjunct starter concept for modulating the cheese characteristics. These adjunct cultures provide added value to the cheese without affecting its primary cheese manufacturing process. In addition, modification of cheese and whey processing can be achieved by using selected enzymes, i.e. an Aspergillus niger carboxy-peptidase is found to accelerate the flavour development and reduce bitterness in cheese, and a novel peroxidase isolated from the mushroom Marasmius scorodonius gives reduced levels of annato-derived colour in whey without adverse side-effects on flavour and functionality of the whey. Aust. J. Dairy Technol. 65, 159-161
The Victorian Food Act 1984 (s.44) allows for a food recall to be made where there is reasonable grounds to believe that a recall is necessary to prevent or reduce the possibility of a serious danger to public health or to mitigate the adverse consequences of an identified serious danger to public health. This paper discusses the food regulatory framework in Victoria, outlining responsibilities and interactions between regulators, and the type of information that informs effective decision-making processes in a timely manner.
This study examined two commercial Australian organic cheddar cheeses (A and B) for the presence of antimicrobial, antioxidant and antihypertensive activities. The antimicrobial activity of the peptides was determined by the growth inhibition of Escherichia coli, Bacillus cereus and Staphylococcus aureus. The bacteria were inhibited the greatest by the whole peptide extracts derived from organic cheddar cheese A. Overall, B. cereus was inhibited the most by fractionated peptides derived from organic cheddar cheese A between >5 kDa and <10 kDa (34.6%), followed by E. coli (28%), which was inhibited the most by fractionated peptides greater than 10 kDa derived from organic cheddar cheese A. Antioxidant activity was determined by the inhibition of the free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH). Overall, both organic cheddar cheese peptide extracts had similar inhibition. No significant differences (p>0.05) were observed. Antihypertensive activity was determined by inhibition of the angiotensin l-converting enzyme. Overall, organic cheddar cheese B peptides less than 5 kDa had the lowest IC50 value (0.114 mg/mL), followed closely by the fraction containing peptides between 5 kDa and 10 kDa from organic cheddar cheese B (0.122 mg/mL). This study has shown that peptides derived from Australian organic cheddar cheeses potentially have antioxidant, antihypertensive and antioxidant properties. Aust. J. Dairy Technol. 65, 170-173
