Genomic Analyses of Pediococcus pentosaceus ST65ACC, a Bacteriocinogenic Strain Isolated from Artisanal Raw-Milk Cheese

The implementation of quality assurance schemes for the assessment of PDO food authenticity is an issue involving manufacturers, traders, retailers and consumers. In this respect, reliable analytical methods are needed to integrate paper-trailing information. The feasibility of distinguishing the Italian Fontina PDO cheese from the generic Fontal cheese was preliminarily evaluated on a set of commercial samples by measuring selected parameters (pH, alkaline phosphatase activity, content of copper, volatiles, extent of proteolysis) related to the different manufacturing processes. The relative profile of free amino acids proved to be a promising tool. A new set of 41 samples of Fontina PDO cheese was collected at representative dairies within the recognized production area and analyzed for free amino acids. A chemometric model of Fontina PDO cheese was built based on the mean content and standard deviation of 15 free amino acids. On this basis, all of the PDO samples were correctly identified, whereas all of the Fontal cheeses were recognized as different cheeses.

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Molecular approaches to analysing the microbial composition of raw milk and raw milk cheese

International Journal of Food Microbiology ◽

10.1016/j.ijfoodmicro.2011.08.001 ◽

2011 ◽

Vol 150 (2-3) ◽

pp. 81-94 ◽

Cited By ~ 129

Author(s):

Lisa Quigley ◽

Orla O'Sullivan ◽

Tom P. Beresford ◽

R. Paul Ross ◽

Gerald F. Fitzgerald ◽

...

Keyword(s):

Raw Milk ◽

Microbial Composition ◽

Molecular Approaches ◽

Raw Milk Cheese

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Biochemical changes during the ripening of homemade ‘San Simón da Costa’ raw milk cheese

International Journal of Dairy Technology ◽

10.1111/j.1471-0307.2008.00364.x ◽

2008 ◽

Vol 61 (1) ◽

pp. 80-89 ◽

Cited By ~ 4

Author(s):

E L NHUCH ◽

B PRIETO ◽

I FRANCO ◽

A BERNARDO ◽

J CARBALLO

Keyword(s):

Raw Milk ◽

Biochemical Changes ◽

Raw Milk Cheese

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HIGH-PRESSURE DESTRUCTION KINETICS OF SPOILAGE AND PATHOGENIC BACTERIA IN RAW MILK CHEESE

Journal of Food Process Engineering ◽

10.1111/j.1745-4530.2007.00114.x ◽

2007 ◽

Vol 30 (3) ◽

pp. 357-374 ◽

Cited By ~ 16

Author(s):

Y. SHAO ◽

H.S. RAMASWAMY ◽

S. ZHU

Keyword(s):

High Pressure ◽

Pathogenic Bacteria ◽

Raw Milk ◽

Destruction Kinetics ◽

Raw Milk Cheese ◽

Kinetics Of

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Enterotoxin-producing Staphylococcus aureus genotype B as a major contaminant in Swiss raw milk cheese

Journal of Dairy Science ◽

10.3168/jds.2013-7643 ◽

2014 ◽

Vol 97 (3) ◽

pp. 1305-1312 ◽

Cited By ~ 34

Author(s):

J. Hummerjohann ◽

J. Naskova ◽

A. Baumgartner ◽

H.U. Graber

Keyword(s):

Staphylococcus Aureus ◽

Raw Milk ◽

Raw Milk Cheese

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Genome Sequence and Annotation of a Human Infection Isolate of Escherichia coli O26:H11 Involved in a Raw Milk Cheese Outbreak

Genome Announcements ◽

10.1128/genomea.01568-14 ◽

2015 ◽

Vol 3 (1) ◽

Cited By ~ 5

Author(s):

Wessam Galia ◽

Patricia Mariani-Kurkdjian ◽

Estelle Loukiadis ◽

Stéphanie Blanquet-Diot ◽

Françoise Leriche ◽

...

Keyword(s):

Escherichia Coli ◽

Genome Sequence ◽

Raw Milk ◽

Human Infection ◽

Raw Milk Cheese

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Effect of Phage on Survival of Salmonella Enteritidis during Manufacture and Storage of Cheddar Cheese Made from Raw and Pasteurized Milk

Journal of Food Protection ◽

10.4315/0362-028x-64.7.927 ◽

2001 ◽

Vol 64 (7) ◽

pp. 927-933 ◽

Cited By ~ 108

Author(s):

RAJESH MODI ◽

Y. HIRVI ◽

A. HILL ◽

M. W. GRIFFITHS

Keyword(s):

Lactic Acid ◽

Salmonella Enteritidis ◽

Cheddar Cheese ◽

Raw Milk ◽

Final Concentration ◽

Pasteurized Milk ◽

Ph Values ◽

Standard Procedures ◽

Raw Milk Cheese ◽

And Storage

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.

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Characteristics of Shiga Toxin–Producing Escherichia coli Isolated from Swiss Raw Milk Cheese within a 3-Year Monitoring Program

Journal of Food Protection ◽

10.4315/0362-028x-73.1.88 ◽

2010 ◽

Vol 73 (1) ◽

pp. 88-91 ◽

Cited By ~ 36

Author(s):

C. ZWEIFEL ◽

N. GIEZENDANNER ◽

S. CORTI ◽

G. KRAUSE ◽

L. BEUTIN ◽

...

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Monitoring Program ◽

Raw Milk ◽

Health Impact ◽

Toxin Gene ◽

Genes Encoding ◽

Raw Milk Cheese ◽

Human Infections ◽

Hard Cheese

Food is an important vehicle for transmission of Shiga toxin–producing Escherichia coli (STEC). To assess the potential public health impact of STEC in Swiss raw milk cheese produced from cow's, goat's, and ewe's milk, 1,422 samples from semihard or hard cheese and 80 samples from soft cheese were examined for STEC, and isolated strains were further characterized. By PCR, STEC was detected after enrichment in 5.7% of the 1,502 raw milk cheese samples collected at the producer level. STEC-positive samples comprised 76 semihard, 8 soft, and 1 hard cheese. By colony hybridization, 29 STEC strains were isolated from 24 semihard and 5 soft cheeses. Thirteen of the 24 strains typeable with O antisera belonged to the serogroups O2, O22, and O91. More than half (58.6%) of the 29 strains belonged to O:H serotypes previously isolated from humans, and STEC O22:H8, O91:H10, O91:H21, and O174:H21 have also been identified as agents of hemolytic uremic syndrome. Typing of Shiga toxin genes showed that stx1 was only found in 2 strains, whereas 27 strains carried genes encoding for the Stx2 group, mainly stx2 and stx2vh-a/b. Production of Stx2 and Stx2vh-a/b subtypes might be an indicator for a severe outcome in patients. Nine strains harbored hlyA (enterohemorrhagic E. coli hemolysin), whereas none tested positive for eae (intimin). Consequently, semihard and hard raw milk cheese may be a potential source of STEC, and a notable proportion of the isolated non-O157 STEC strains belonged to serotypes or harbored Shiga toxin gene variants associated with human infections.

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