Effect of temperature during early stage of curing upon cheddar cheese characteristics (original) (raw)
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Nutritive and bacteriological analysis of different types of cheese
Chittagong University Journal of Biological Sciences, 2013
In the present investigation five cheese samples were collected and their pH and moisture contents were determined which was found to vary from 6.0 to 6.5 and 35.0-40.0% respectively. Major nutritional factors protein (1N NaOH soluble) and fat (chloroform soluble) of the samples were also analyzed and found 57.9 to 100.0 mg/g protein and 15-25% fat. The samples showed higher number of total bacterial count (5.3×104 - 2.9×107cfu/g) than the load of Lactobacilli (1.9x105 cfu/g) and Streptococci (2.1x105cfu/g). All the isolates were grouped into six on the basis of their morphological and cultural features. Six isolates were selected on the basis of their morphological, cultural, physiological and biochemical characteristics. An attempt was made to identify the isolates. They were found to belong to the three genera viz. Bacillus (S1X3, S1X8, S2Y1, and S2Y2), Staphylococcus (S1X7) and Planococcus (S1X11). They were provisionally identified as Bacillus fastidiosus (S1X3); B. sphaericus ...
The effect of non-starter bacteria on the chemical composition and the flavour of Cheddar cheese
Journal of Dairy Research, 1976
SummaryDifferences in flavour scores and in the concentrations of free fatty acids, methyl ketones and H2S were measured in Cheddar cheeses containing various groups of non-starter bacteria or starter streptococci alone, made under controlled bacteriological conditions by the aseptic vat technique. The non-starter bacteria were made up of lactobacilli, leuconostocs, pediococci, micrococci and Gram-negative rods isolated in commercial creameries from raw milk or fresh cheese curd. These were added to the experimental cheese as single groups or as complete floras (reference floras). Several bacterial groups influenced the measured concentrations of the flavour compounds, but flavour differences were not correlated with these chemical differences. Only cheese containing a curd-derived whole reference flora or cheese made in open vats in the N.I.R.D. Experimental Dairy had significantly better flavour than starter-only cheese, but this improvement was not attributable to any particular ...
Microorganisms influence on quality and flavor of cheese
2016
For this study information about microorganism in cheese and their effect on the final product was gained from science databases, e.g. Science Direct, Web of Science and Prima. The taxonomic structures of microbial communities in cheese can be studied by culture-dependent and culture independent methods. Some problems with production of cheese are early and late gas formation and growth of pathogens. Although these problems can be counteracted by sanitation, adding nitrate, microfiltration, bactofugation, lower water activity and by lowering the pH, they can give the cheese inferior quality. Biological hazards can be avoided by good sanitation. For a good shelf-life cheese, techniques such as fermentation and pasteurization are important. Lactic acid bacteria are very important for flavor development and toxin-producing bacteria can in combination with resistant bacteria be used to control flavor development.
Journal of Dairy Science, 2022
Traditionally, starter cultures for Cheddar cheese are combinations of Lactococcus lactis and Lactococcus cremoris. Our goal was to compare growth and survival of individual strains during cheesemaking, and after salting and pressing. Cultures used were 2 strains of L. lactis (SSM 7605, SSM 7436) and 2 strains of L. cremoris (SSM 7136, SSM 7661). A standardized Cheddar cheese make procedure was used that included a 38°C cook temperature and salting levels of 2.0, 2.4, 2.8, 3.2, and 3.6% from which were selected cheeses with salt-in-moisture levels of 3.5, 4.5, and 5.5%. Vats of cheese were made using each strain on its own as biological duplicates on different days. Starter culture numbers were enumerated by plate counting during cheesemaking and after 6 d storage at 6°C. Flow cytometry with fluorescent staining by SYBR Green and propidium iodide was used to determine the number of live and dead cells in cheese at the different salt levels. Differences in cheese make times were strain dependent rather than species dependent. Even with correction for average culture chain length, cheeses made using L. lactis strains contained ~4 times (~0.6 log) more bacterial cells than those made using L. cremoris strains. Growth of the strains used in this study was not influenced by the amount of salt added to the curd. The higher pH of cheeses with higher salting levels was attributed to those cheeses having a lower moisture content. Based on flow cytometry, ~5% of the total starter culture cells in the cheese were dead after 6 d of storage. Another 3 to 19% of the cells were designated as being live, but semipermeable, with L. cremoris strains having the higher number of semipermeable cells.
Investigation of Some Microbiological and Chemical Properties of Different Cheeses
Bitlis Eren Üniversitesi Fen Bilimleri Dergisi, 2020
In this study, some microbiological and chemical analyses were performed on samples of kashar, chechil, lor and white cheeses produced in the region of Kars. The samples were microbiologically evaluated in means of total aerob mesophilic bacteria, coliform group bacteria, Escherichia coli, Enterobacteriaceae, Staphylococci-Micrococci, yeast-mold, Salmonella spp. and Listeria monocytogenes. The pH values of cheese samples were determined by pH-meter, acidity and salt content by titration method, fat content by Gerber method and moisture content by gravimetric method. The chemical analyses were completed and investigated for compliance with Turkish standards. Of the examined kashar cheese samples, 28% in terms of salt content and 40% in terms of moisture content did not meet Turkish standards. Of the chechil cheese samples, 60% in terms of salt content and 40% in terms of moisture content did not meet Turkish standards. Of the lor cheese samples, 4% contained L. monocytogenes, while 20% in terms of salt content and 28% in terms of moisture content did not meet Turkish standards. Of the white cheese samples, 8% contained L. monocytogenes, while 48% in terms of salt content and 28% in terms of moisture content did not meet Turkish standards It was determined that some of the cheese samples examined in accordance with the obtained results may pose a risk in microbiological terms and do not comply with the relevant standards in terms of chemistry.
Starter strain related effects on the biochemical and sensory properties of Cheddar cheese
The Journal of dairy research, 2007
A detailed investigation was undertaken to determine the effects of four single starter strains, Lactococcus lactis subsp. lactis 303, Lc. lactis subsp. cremoris HP, Lc. lactis subsp. cremoris AM2, and Lactobacillus helveticus DPC4571 on the proteolytic, lipolytic and sensory characteristics of Cheddar cheese. Cheeses produced using the highly autolytic starters 4571 and AM2 positively impacted on flavour development, whereas cheeses produced from the poorly autolytic starters 303 and HP developed off-flavours. Starter selection impacted significantly on the proteolytic and sensory characteristics of the resulting Cheddar cheeses. It appeared that the autolytic and/or lipolytic properties of starter strains also influenced lipolysis, however lipolysis appeared to be limited due to a possible lack of availability or access to suitable milk fat substrates over ripening. The impact of lipolysis on the sensory characteristics of Cheddar cheese was unclear, possibly due to minimal differ...
2014
A potentially hazardous food (PHF) requires time/temperature control to maintain safety. The US Food and Drug Administration would classify most cheeses as PHF based on pH and a w, and a product assessment would be required to evaluate safety for >6 h storage at 21°C. We tested the ability of 67 market cheeses to support growth of Listeria monocytogenes (LM), Salmonella spp. (SALM), Escherichia coli O157:H7 (EC), and Staphylococcus aureus (SA) over 15-day storage at 25°C. Hard (Asiago and Cheddar), semi-hard (Colby and Havarti), and soft cheeses (Mozzarella and Mexican-style) were among types tested, and included some reducedsodium and reduced-fat types. Single-pathogen cocktails were prepared and individually inoculated onto cheese slices (~10 5 CFU/g). Cocktails were comprised of 10 strains of LM, six of SALM, or five of EC or SA. Inoculated slices were vacuum packaged and stored at 25˚C for < 15 days, with surviving inocula enumerated every three days. Salt-in-the-moisture phase (%SMP), calculated from measured moisture (%) and salt (%), titratable acidity (%), pH, and a w were measured. Pathogens did not grow on 53 cheeses, while 14 cheeses supported growth of SA, six of SALM, four of LM, and three of EC. Of the cheeses supporting pathogen growth, all supported growth of SA, ranging from 0.57 to 3.08 log CFU/g (avg. 1.70 log CFU/g). Growth of SALM, LM, and EC ranged from 1.01 to 2.05 log CFU/g (avg. 2.05 log CFU/g), 0.60 to 2.68 log CFU/g (avg. 1.60 CFU/g), and 0.41 to 2.90 log CFU/g (avg. 1.69 CFU/g), respectively. Cheese pH and %SMP most affected pathogen growth, with pH having a dominant effect. Pathogen growth/no-growth varied within some cheese types or lots. Except for Swiss-type cheeses, moldor bacterial-ripened cheeses, and cheeses made with non-bovine milk where insufficient data exists, the pathogen growth/no-growth interface could be modeled and boundary conditions established for safe, extended storage (<25°C) of cheeses based on pH and %SMP.
Journal of Dairy Science, 2012
The aim of this study was to evaluate the influence of different storage temperatures and delivery system of the milk on the microbiological and physicochemical characteristics of Grana Trentino, a long-ripened hardcooked Italian cheese. In particular, 3 kinds of milk storage and delivery were studied: milk delivered to the dairy in the traditional manner without temperature control, milk delivered at 18°C, and milk stored at the farm and delivered at 12°C. Milk, natural whey starter, and cheeses after 18 mo of ripening were sampled for microbiological profiles, physicochemical analysis, and proteolysis evaluation, and a study of cheese volatile compounds through a solid-phase microextraction gas chromatography-mass spectrometry technique was performed. Milk microbiota was not affected by any of the treatments. At the end of ripening, free fatty acid and ester contents were significantly higher in cheeses from milk without temperature control. This was probably due to the milk delivery to the dairy in churns causing the fat globule membrane break during transport and, consequently, a greater release of fat and deeper lipolysis. Milk refrigeration at 12°C for 12 h before delivery affected the distribution of nitrogen fractions in cheeses. Lower temperatures of milk storage favored a larger soluble nitrogen fraction and greater cheese proteolysis, probably caused by an enhanced plasmin activity. From this work, it is concluded that both milk temperature storage and transport system could affect cheese ripening, leading to significant differences in chemical compounds: if milk was delivered by churns, higher free fatty acid and ester content in cheeses was observed; if milk was stored at 12°C for 12 h before delivery, greater cheese proteolysis was induced with consequent faster ripening.