scholarly journals Inactivation of Staphylococcus aureus in raw milk cheese by combinations of high-pressure treatments and bacteriocin-producing lactic acid bacteria

2005 ◽  
Vol 98 (2) ◽  
pp. 254-260 ◽  
Author(s):  
J.L. Arques ◽  
E. Rodriguez ◽  
P. Gaya ◽  
M. Medina ◽  
B. Guamis ◽  
...  
2005 ◽  
Vol 71 (7) ◽  
pp. 3399-3404 ◽  
Author(s):  
Eva Rodriguez ◽  
Juan L. Arques ◽  
Manuel Nuñez ◽  
Pilar Gaya ◽  
Margarita Medina

ABSTRACT The effect of high-pressure (HP) treatments combined with bacteriocins of lactic acid bacteria (LAB) produced in situ on the survival of Escherichia coli O157:H7 in cheese was investigated. Cheeses were manufactured from raw milk inoculated with E. coli O157:H7 at approximately 105 CFU/ml. Seven different bacteriocin-producing LAB were added at approximately 106 CFU/ml as adjuncts to the starter. Cheeses were pressurized on day 2 or 50 at 300 MPa for 10 min or 500 MPa for 5 min, at 10°C in both cases. After 60 days, E. coli O157:H7 counts in cheeses manufactured without bacteriocin-producing LAB and not pressurized were 5.1 log CFU/g. A higher inactivation of E. coli O157:H7 was achieved in cheeses without bacteriocin-producing LAB when 300 MPa was applied on day 50 (3.8-log-unit reduction) than if applied on day 2 (1.3-log-unit reduction). Application of 500 MPa eliminated E. coli O157:H7 in 60-day-old cheeses. Cheeses made with bacteriocin-producing LAB and not pressurized showed a slight reduction of the pathogen. Pressurization at 300 MPa on day 2 and addition of lacticin 481-, nisin A-, bacteriocin TAB 57-, or enterocin AS-48-producing LAB were synergistic and reduced E. coli O157:H7 counts to levels below 2 log units in 60-day-old cheeses. Pressurization at 300 MPa on day 50 and addition of nisin A-, bacteriocin TAB 57-, enterocin I-, or enterocin AS-48-producing LAB completely inactivated E. coli O157:H7 in 60-day-old cheeses. The application of reduced pressures combined with bacteriocin-producing LAB is a feasible procedure to improve cheese safety.


2017 ◽  
Vol 14 (2) ◽  
pp. 587-591
Author(s):  
K. Mchiouer ◽  
S. Bennani ◽  
N. Sh. El-Gendy ◽  
M. Meziane

ABSTRACT: The aim of this study is to determine the microbiological quality of raw cows’ milk of Oujda city. Raw milk samples are collected randomly between June 2014 and May 2015 from 20 Mahlaba (dairies) for microbiological evaluation. The samples are analyzed to determine total mesophilic aerobic bacteria (TMAB), total coliform, fecal coliform, staphylococcus aureus, fecal streptococci, proteolytic bacteria and lactic acid bacteria. The results of bacterial count showed that there is a variation between all the milk samples and a period effect is also observed. The mean counts of total mesophilic aerobic bacteria from all sale points are between 1.76×106 and 40.17×106 CFU/ml. Milk samples reveled counts total coliform and fecal coliform ranging from 0.58×105 to 11.10×105 CFU/ml and from 0.60×103 to 14.64×103 CFU/ml, respectively. Staphylococcus aureus are also detected in all samples with counts ranging from 0.35 ×103 to 3.08×103 CFU/ml. Fecal streptococci are found in all milk samples, at counts ranging from 0.16 ×102 to 2.18 ×102 CFU/ml. And finally, proteolytic and lactic acid bacteria are between 0.3×103 and 2.86×103 CFU/ml and 2.37×106 and 24.14 ×106 CFU/ml respectively. These results indicate a lack of compliance with good manufacturing practice at milking, collection and transportation of raw milk.


2001 ◽  
Vol 68 (1) ◽  
pp. 131-137 ◽  
Author(s):  
EVA RODRÍGUEZ ◽  
JUAN LUIS ARQUÉS ◽  
PILAR GAYA ◽  
MANUEL NUÑEZ ◽  
MARGARITA MEDINA

The ability of Listeria monocytogenes to grow at low temperatures and increase to hazardous levels during storage of dairy products is of great concern to the dairy industry. List. monocytogenes was detected in 3·6% of 774 cows' milk samples from 114 farms in Central Spain (Gaya et al. 1998). Ewes' and goats' milks produced in Spain had contamination levels of 2·2 and 2·6% respectively (Rodríguez et al. 1994; Gaya et al. 1996). List. monocytogenes may survive during the manufacture and ripening of most cheese varieties, with higher risk in soft surface-ripened cheeses owing to the rise in pH during ripening (Maisnier-Patin et al. 1992; Giraffa & Carminati, 1997).The efficacy with which actively growing bacteriocin-producing cultures inhibit List. monocytogenes in some cheese varieties has been demonstrated. Nisin-producing starters inhibited List. monocytogenes V7 in Camembert cheese (Maisnier-Patin et al. 1992) and List. innocua BL86/26 in raw ewes' milk Manchego cheese (Rodríguez et al. 1998). A lacticin 3147-producing starter culture (McAuliffe et al. 1999) reduced List. monocytogenes Scott A levels in cottage cheese. Inoculation of milk with enterocin AS-48-producing Enterococcus faecalis INIA 4 inhibited List. monocytogenes strains Ohio and Scott A during the manufacture and ripening of Manchego cheese (Nuñez et al. 1997).Semi-hard cheese varieties from raw or pasteurized cows' milk mixed with different proportions of ewes' and/or goats' milk represent ∼ 50% of Spanish cheese production. The objective of the present work was to evaluate the antilisterial activity of three bacteriocin-producing lactic acid bacteria strains isolated from milk (Rodríguez et al. 2000) during the manufacture and ripening of a semi-hard cheese manufactured from raw milk.


2021 ◽  
pp. 1-7
Author(s):  
Harutoshi Tsuda ◽  
Kana Kodama

Abstract This paper reveals the technological properties of lactic acid bacteria isolated from raw milk (colostrum and mature milk) of Wagyu cattle raised in Okayama Prefecture, Japan. Isolates were identified based on their physiological and biochemical characteristics as well as 16S rDNA sequence analysis. Streptococcus lutetiensis and Lactobacillus plantarum showed high acid and diacetyl-acetoin production in milk after 24 h of incubation at 40 and 30°C, respectively. These strains are thought to have potential for use as starter cultures and adjunct cultures for fermented dairy products.


2014 ◽  
Vol 97 (3) ◽  
pp. 1305-1312 ◽  
Author(s):  
J. Hummerjohann ◽  
J. Naskova ◽  
A. Baumgartner ◽  
H.U. Graber

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.


Sign in / Sign up

Export Citation Format

Share Document