Lactobacilli in Cheddar cheese

1959 ◽  
Vol 26 (2) ◽  
pp. 157-161 ◽  
Author(s):  
C. K. Johns ◽  
Shirley E. Cole

The numbers of lactobacilli present in milk for cheese-making and in the cheese at various stages of ripening, have been determined for 38 Cheddar cheeses made during studies on flavour enhancement. These organisms multiplied rapidly even during the first few days of curing. Maximum levels were attained at 3–6 months; at 1 year counts had declined appreciably.Flavour intensity in the experimental cheese appeared to be correlated with the level of lactobacilli present in (a) milk at the start of cheese-making and (b) at subsequent stages of ripening. These two count levels were usually closely correlated. Factory raw milk had the highest counts and gave the highest degree of flavour, followed by similar milk pasteurized and inoculated with selected strains of lactobacilli.

1979 ◽  
Vol 46 (3) ◽  
pp. 497-509 ◽  
Author(s):  
Barry A. Law ◽  
Anthony T. Andrews ◽  
Allan J. Cliffe ◽  
M. Elisabeth Sharpe ◽  
Helen R. Chapman

SummaryThe effect of proteolytic, psychrotrophic strains of Pseudomonas fluorescens, Ps. putida and Acinetobacter spp. on cheese-making with stored milk has been investigated. Ps. fluorescens and Ps. putida growing for 72 h in raw milk at 7·5 °C to levels of approx. 107 colony-forming units/ml caused a low degree of β- and к-casein breakdown detectable by gel electrophoresis, but this was insufficient to affect N losses in whey or cheese yields. Variations in cheese-making times with pasteurized milks were not attributable to the counts of psychrotrophs in the corresponding raw milks. The water-soluble and TCA-soluble N fractions of maturing cheeses were unaffected by psychrotroph counts in raw milks, but small differences in levels of casein fractions of cheeses made from milks stored for 72 h were detected by quantitative polyacrylamide gel electrophoresis. The incidence of casein breakdown in raw milk and subsequently in cheese were not necessarily related. None of the cheeses developed off flavour related to excessive protein breakdown but many became lipolytically rancid, despite the selection of strains with low lipolytic activity on a diagnostic medium. It is concluded that the numbers of psychrotrophic bacteria likely to occur in stored raw milk under commercial conditions are unlikely to cause significant changes in the yields or quality of Cheddar cheese through their proteolytic activity.


1931 ◽  
Vol 2 (2) ◽  
pp. 176-178 ◽  
Author(s):  
George M. Moir

The preceding investigation left a little doubt as to the effect produced by pasteurisation of clean milk upon the flavour of the mature cheese. For although the cheese made from milk, flash-pasteurised at 165° F., appeared to develop a desirable flavour more rapidly than the raw control throughout the greater part of the ripening period, yet at the end this was spoilt by a very slight bitterness.


2001 ◽  
Vol 64 (7) ◽  
pp. 927-933 ◽  
Author(s):  
RAJESH MODI ◽  
Y. HIRVI ◽  
A. HILL ◽  
M. W. GRIFFITHS

The ability of Salmonella Enteritidis to survive in the presence of phage, SJ2, during manufacture, ripening, and storage of Cheddar cheese produced from raw and pasteurized milk was investigated. Raw milk and pasteurized milk were inoculated to contain 104 CFU/ml of a luminescent strain of Salmonella Enteritidis (lux) and 108 PFU/ml SJ2 phage. The milks were processed into Cheddar cheese following standard procedures. Cheese samples were examined for Salmonella Enteritidis (lux), lactic acid bacteria, molds and yeasts, coliforms, and total counts, while moisture, fat, salt, and pH values were also measured. Salmonella Enteritidis (lux) was enumerated in duplicate samples by surface plating on MacConkey novobiocin agar. Bioluminescent colonies of Salmonella Enteritidis were identified in the NightOwl molecular imager. Samples were taken over a period of 99 days. Counts of Salmonella Enteritidis (lux) decreased by 1 to 2 log cycles in raw and pasteurized milk cheeses made from milk containing phage. In cheeses made from milks to which phage was not added, there was an increase in Salmonella counts of about 1 log cycle. Lower counts of Salmonella Enteritidis (lux) were observed after 24 h in pasteurized milk cheese containing phage compared to Salmonella counts in raw milk cheese with phage. Salmonella Enteritidis (lux) survived in raw milk and pasteurized milk cheese without phage, reaching a final concentration of 103 CFU/g after 99 days of storage at 8°C. Salmonella did not survive in pasteurized milk cheese after 89 days in the presence of phage. However, Salmonella counts of approximately 50 CFU/g were observed in raw milk cheese containing phage even after 99 days of storage. In conclusion, this study demonstrates that the addition of phage may be a useful adjunct to reduce the ability of Salmonella to survive in Cheddar cheese made from both raw and pasteurized milk.


1911 ◽  
Vol 72 (1877supp) ◽  
pp. 408-411
Author(s):  
G. C. Sawyers
Keyword(s):  

1984 ◽  
Vol 47 (7) ◽  
pp. 530-531 ◽  
Author(s):  
MICHAEL H. BRODSKY

One hundred twenty-seven 60-d aged Cheddar cheese samples produced by 21 provincially inspected cheese plants were analyzed by 8 regional laboratories of the Ontario Ministry of Health. Coliforms were detected in 37 (31.2%) and fecal coliforms confirmed in 22 (18.3%) samples, with geometric mean counts per g of 92.5 and 79.3, respectively. Staphylococcus aureus was found in only two products at a level of >1000 per g. Salmonella spp. and Campylobacter jejuni were not isolated from any of the samples tested. Yersinia enterocolitica was isolated from one product; however, the isolate was bile esculin-and salicin-positive, and considered a non-pathogenic biotype. The pH of these aged Cheddars ranged between 4.98 and 5.50, with a mean of 5.26. Alkaline phosphatase activity was detected in 94 (79.7%) of the 118 samples tested. These results suggest that 60-d aged raw milk Cheddar cheese produced in Ontario does not pose a significant bacteriological health risk.


2017 ◽  
Vol 108 (2) ◽  
pp. 103
Author(s):  
Aikaterini GEORGALA

<p>This review focuses on the lipolysis profile of some non European raw milk cheese varieties. Lipolysis data of some traditional/artisanal non-European raw milk cheeses such as cheeses ripened in an animal skin, cheeses ripened in brine, cheeses produced in small scale by local dairies etc., are collected and presented in this study. The main characteristics of these cheeses and their lipolysis profile in general are discussed. Factors such as the type of cheese, the technology applied for cheese making and the age of cheese are shown to influence the lipolysis profile.</p>


1981 ◽  
Vol 64 (11) ◽  
pp. 2270-2277 ◽  
Author(s):  
R.K. Thunell ◽  
W.E. Sandine ◽  
F.W. Bodyfelt
Keyword(s):  

2012 ◽  
Vol 16 ◽  
pp. 391-397 ◽  
Author(s):  
Giorgio Marchesini ◽  
Stefania Balzan ◽  
Filomena Montemurro ◽  
Luca Fasolato ◽  
Igino Andrighetto ◽  
...  

1972 ◽  
Vol 39 (2) ◽  
pp. 261-273 ◽  
Author(s):  
Margaret L. Green

SummaryThree enzymes were assessed as rennet substitutes for cheese-making. The bovine and chicken pepsins used were relatively crude extracts of bovine stomach mucosa and chicken proventriculae respectively; the swine pepsin was a partially purified commercial product. The ratios of milk-clotting activity to general proteolytic activity were high for rennet and bovine pepsin and low for swine and chicken pepsins. Both bovine mucosa and chicken stomach gave low milk-clotting activities compared with calf stomach. For all the enzymes the chemical reactions causing milk clotting appeared to be the same. The milk-clotting activity showed a decrease with increase in substrate pH for all the enzymes, although they were all still active at pH 6·81.Duplicate cheeses were made from each of the swine, bovine and chicken pepsins, with rennet as a standard in each trial. The cheese-making process was similar with each enzyme, but differences appeared during ripening. The chicken-pepsin cheeses had poor body and weak Cheddar-cheese flavour, with many and intense off-flavours. The cheeses made with bovine and swine pepsins were only slightly inferior in quality and intensity of Cheddar-cheese flavour to the rennet cheeses. From a simulated cheese-making experiment it was concluded that 30–40 % of the added rennet, bovine pepsin and chicken pepsin was probably inactivated during the cheese-making process and that most or all of the swine pepsin was lost. These results provide an explanation for the variations observed in cheese ripening.It was concluded that chicken pepsin would not prove a suitable rennet substitute for making Cheddar cheese because of the quality of the cheese produced, and that bovine pepsin would not prove suitable because of the cost of preparing a suitable extract. Swine pepsin would appear to be suitable if the ripening time were to be lengthened or if another enzyme were to be added to assist ripening; it is cheaper than rennet and other rennet substitutes.


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