Fate of Aflatoxin M1 in Cheddar Cheese and in Process Cheese Spread

1982 ◽  
Vol 45 (6) ◽  
pp. 549-552 ◽  
Author(s):  
ROBERT E. BRACKETT ◽  
ELMER H. MARTH
Keyword(s):  
Analytical Method ◽  
Cheddar Cheese ◽  
Aflatoxin M1 ◽  
Processing Conditions ◽  
Ripening Period ◽  
Process Cheese

Four batches of stirred-curd Cheddar cheese were prepared, using milk which was naturally contaminated with aflatoxin M1. This cheese was analyzed for aflatoxin M1 content at intervals while the cheese ripened for about 1 year. Levels of aflatoxin M1 detected in cheese started low, increased and then leveled off for the remainder of the ripening period. This cheese was used to make process cheese spread. The spread appeared to contain as much or more aflatoxin M1 as the cheese from which it was made. The aflatoxin M1 content of cheese spread appeared to increase, and then return to near original levels during storage at 7°C. Contaminated Cheddar cheese was treated with heat (90°C for 20 min), emulsifying salt (5% Na2HPO4) or both to determine the influence of processing conditions on aflatoxin M1. Samples treated with emulsifying salt or heat showed an increase in aflatoxin M1 content but not as much as when samples were treated with both. The apparent increased in aflatoxin M1 content in natural cheese and in process cheese spread may be associated with greater recovery of toxin by the analytical method as cheese ripens or is treated to make the process cheese spread.

20. Pasteurised Milk for Cheddar Cheese Making. II: The Mineral Content of Cheddar Cheese

1931 ◽  
Vol 2 (2) ◽  
pp. 176-178 ◽  
Author(s):  
George M. Moir
Keyword(s):  
Mineral Content ◽  
Cheddar Cheese ◽  
Ripening Period ◽  
Cheese Making

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.

Histamine Production in Low-Salt Cheddar Cheese

1991 ◽  
Vol 54 (11) ◽  
pp. 852-860 ◽  
Author(s):  
JAYNE E. STRATTON ◽  
ROBERT W. HUTKINS ◽  
STEVE L. TAYLOR
Keyword(s):  
Low Temperature ◽  
Trichloroacetic Acid ◽  
Phosphotungstic Acid ◽  
Cheddar Cheese ◽  
Ripening Period ◽  
Histamine Production ◽  
Low Salt ◽  
Histamine Formation ◽  
Low Levels ◽  
Control Milk

To assess the potential for histamine production in low-salt Cheddar cheese, pasteurized milk was inoculated with Lactobacillus buchneri St2A at levels of 102, 103, and 104 microorganisms per ml of milk. One additional vat was uninoculated and served as a control. Milk was then manufactured into low-salt (0.40%) Cheddar cheese. After 180 d of aging at 7°C, levels of L. buchneri St2A had increased approximately 100-fold in the inoculated cheese. Proteolysis, expressed as μmoles free glycine per g cheese, increased from 40 to 150 (trichloroacetic acid soluble) and from 25 to 130 (phosphotungstic acid soluble) during the ripening period. Histamine levels, however, remained low in the inoculated cheeses (<5 mg/100 g), suggesting that the potential for histamine formation may be minimal in low-salt Cheddar cheese. It was concluded that the relatively low levels of proteolysis and low temperature of storage were primarily responsible for inhibiting histamine production.

Survival of some non-starter bacteria in naturally ripened and enzyme-accelerated Cheddar cheese

1988 ◽  
Vol 55 (4) ◽  
pp. 597-602 ◽  
Author(s):  
Lydia Bautista ◽  
Rohan G. Kroll
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Enterococcus Faecalis ◽  
Enzyme System ◽  
Cheddar Cheese ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Ripening Period ◽  
Gram Positive Bacteria

SummaryEffects of the addition of a proteinase (Neutrase 1–5S) and a peptidase (aminopeptidase DP-102) as agents for accelerating the ripening of Cheddar cheese on the survival of some non-starter bacteria (Staphylococcus aureus, Enterococcus faecalis, Escherichia coliand aSalmonellasp.) were studied throughout a 4-month ripening period. The enzymes were found to have no significant effect on the survival of the Gram-positive bacteria but some significant effects were observed, at some stages of the ripening period, with the Gram-negative bacteria in that lower levels were recovered from cheeses treated with the enzyme system.

Effect of the Compositional Factors and Processing Conditions on the Creaming Reaction During Process Cheese Manufacturing

2019 ◽  
Vol 12 (4) ◽  
pp. 575-586 ◽  
Author(s):  
Sonja Lenze ◽  
Alan Wolfschoon-Pombo ◽  
Katrin Schrader ◽  
Ulrich Kulozik
Keyword(s):  
Processing Conditions ◽  
Process Cheese

Aflatoxin: Toxicity to Dairy Cattle and Occurrence in Milk and Milk Products - A Review

1982 ◽  
Vol 45 (8) ◽  
pp. 752-777 ◽  
Author(s):  
RHONA S. APPLEBAUM ◽  
ROBERT E. BRACKETT ◽  
DANA W. WISEMAN ◽  
ELMER H. MARTH
Keyword(s):  
Dairy Cattle ◽  
High Performance ◽  
Raw Milk ◽  
Aflatoxin M1 ◽  
Milk Products ◽  
Blood Constituents ◽  
Dry Milk ◽  
Norsolorinic Acid ◽  
Mixed Function Oxidase System ◽  
Process Cheese

Aflatoxins are toxic and carcinogenic secondary metabolites produced by some common aspergilli during growth on feeds, foods or laboratory media. Aflatoxin B1 (AFB1) is a decaketide (C20-polyketide) which is synthesized by the mold from acetate units via the polyketide pathway. Methionine contributes the methoxy-methyl group. Six known intermediate compounds in the biosynthesis of AFB1 include norsolorinic acid, averantin, averufin, versiconal hemiacetal acetate, versicolorin A and sterigmatocystin. Other aflatoxins (B2, B2a, G1, G2 and G2a) appear to be conversion products of AFB1. When aflatoxins, and in particular AFB1, occur in feed and are consumed by dairy cattle, a variety of symptoms can occur, which includes unthriftiness, anorexia and decreased milk production. Changes in amounts of enzymes and other blood constituents also result from ingestion of AFB1. The hepatic microsomal mixed-function oxidase system of the cow converts some of the ingested AFB1 into aflatoxin M1 (AFM1), which is excreted in milk. AFM1 retains the toxicity of, but is less carcinogenic than AFB1. Certain heat treatments associated with milk processing appear to inactivate a portion of the AFM1 in milk. If raw milk contains AFM1, products (fluid products, nonfat dried milk, cultured milks, natural cheese, process cheese, butter) made from such milk also will contain AFM1. AFM1 appears to be associated with the casein fraction of milk, hence concentrating the casein in the manufacture of products (e.g. cheese, nonfat dry milk) is accompanied by concentrating of the AFM1. Methods involving thin-layer or high-performance liquid chromatography are commonly used to detect and quantify AFM1 in milk and milk products.

Methods for investigating the bacteria in young Cheddar cheese: inhibition of starter streptococci with bacteriophage and α-bromopropionic acid

1960 ◽  
Vol 27 (1) ◽  
pp. 1-7 ◽  
Author(s):  
P. S. Robertson
Keyword(s):  
Pure Culture ◽  
Bacterial Population ◽  
Bacterial Flora ◽  
Cheddar Cheese ◽  
Single Strain ◽  
Normal Culture ◽  
Ripening Period ◽  
Phage Development ◽  
Bacterial Mixtures ◽  
Resistant Cells

SummaryThe investigation of the non-starter bacterial flora of Cheddar cheese during the first few weeks of the ripening period is rendered difficult by the great preponderance of starter streptococci in the bacterial population. It was found that the starter streptococci could be eliminated from agar plates containing various dilutions of the emulsified cheese by the use of phage specific for the pure culture starters used to make the cheese or alternatively by the use of α-bromopropionic acid.The successful use of the phage method of eliminating lactic streptococci from bacterial mixtures in poured agar plates depends on the use of single strain starters, and on the absence of phage-resistant forms in the culture used. The latter objective may be achieved by use of starter strains showing a low proportion of resistant cells in a normal culture and by taking precautions to avoid excessive phage development during the cheesemaking process.

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