scholarly journals Improvement of Raw Milk Cheese Hygiene through the Selection of Starter and Non-Starter Lactic Acid Bacteria: The Successful Case of PDO Pecorino Siciliano Cheese

Author(s):  
Raimondo Gaglio ◽  
Massimo Todaro ◽  
Luca Settanni

This review article focuses on the technological aspects and microbiological critical points of pressed-cooked cheeses processed from raw ewe’s milk without the inoculation of starter cultures, in particular “Pecorino” cheese typology produced in Italy. After showing the composition of the biofilms adhering to the surface of the traditional dairy equipment (mainly wooden vat used to collect milk) and the microbiological characteristics of PDO Pecorino Siciliano cheese manufactured throughout Sicily, this cheese is taken as a case study to develop a strategy to improve its hygienic and safety characteristics. Basically, the natural lactic acid bacterial populations of fresh and ripened cheeses were characterized to select an autochthonous starter and non-starter cultures to stabilize the microbial community of PDO Pecorino Siciliano cheese. These bacteria were applied at a small scale level to prove their in situ efficacy, and finally introduced within the consortium for protection and promotion of this cheese to disseminate their performances to all dairy factories. The innovation in PDO Pecorino Siciliano cheese production was proven to be respectful of the traditional protocol, the final cheeses preserved their typicality, and the general cheese safety was improved. An overview of the future research prospects is also reported.

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.


2014 ◽  
Vol 32 (No. 2) ◽  
pp. 145-151 ◽  
Author(s):  
I. Složilová ◽  
S. Purkrtová ◽  
M. Kosová ◽  
M. Mihulová ◽  
E. Šviráková ◽  
...  

Eight individual bacteriocin-producing lactic acid bacteria (LAB) strains and three bacteriocin-non-producing cheese starter cultures were evaluated for their ability to inhibit the growth of six Listeria monocytogenes strains, originating from the guinea-pig lymph nodes, raw cow milk, and manufacturing dairy equipment. Results showed that either live cells or cell-free neutralised supernatant (CFNS) and/or heated CFNS of six individual LAB strains (Lcc. lactis subsp. lactis CCDM 416 and NIZO R5, Lbc. plantarum HV 11 and DC 1246, P. acidilactici HV 12, and Ent. mundtii CCM 1282) and one starter culture (DELVO-ADD<sup>&reg;</sup> 100-X DSF) were effective in the suppression of at least one listeria strain. Neither any individual LAB strain nor starter culture was antagonistic toward all studied L. monocytogenes strains, indicating diverse sensitivity/resistance among L. monocytogenes strains to antimicrobial compounds of LAB. The significant susceptibility of listerias isolated from raw milk and dairy equipment together with the strong antilisterial activity of DELVO-ADD<sup>&reg; </sup>100-X DSF could be applied in dairy technology, where commonly used starter cultures could play both the biopreservative and fermentation role. &nbsp;


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.


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.


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>


Author(s):  
Maria Tereza Pereira ◽  
Elsa Helena Walter de Santana ◽  
Joice Sifuentes dos Santos

Produtos lácteos fermentados contêm bactérias ácido lácticas (BAL), naturalmente presentes ou adicionadas na matriz láctea como culturas iniciadoras (starters), contribuindo com aroma, textura, valor nutricional e segurança microbiológica. Lactobacillus spp., Streptococcus spp., Lactococcus spp. e Leuconostoc spp. são utilizados como culturas starters em laticínios. As BAL podem ser classificadas em mesofílicas (ex Lactococcus lactis) e termofílicas (ex Streptococcus thermophilus), e de acordo com seus metabólitos de fermentação em homofermentativas (ácido lático) e heterofermentativas (ácido lático, dióxido de carbono, diacetil e outros compostos flavorizantes). Entre as BAL há um grupo de bactérias lácticas que não fazem parte da cultura láctica (non starter lactic acid bacteria - NSLAB), que são oriundas do leite cru, do ambiente de ordenha ou da indústria formando biofilmes. As NSLAB são representadas por espécies heterofermentativas de lactobacilos mesofílicos como Lactobacillus casei spp., L. paracasei spp., L. rhamnosus spp. e L. plantarum spp., e ainda por Pediococcus spp., Leuconostoc spp. e Micrococcus spp. NSLAB termoduricas como Bacillus spp. também são relatadas. As NSLAB em queijos podem ajudar a desenvolver sabor e aroma, porém também são associadas aos defeitos em queijos e leites fermentados. Problemas como odores estranhos, sabor amargo ou muito ácido, perda de viscosidade, perda de coloração, estufamento e formação de gás são associados com a presença e contaminação por NSLAB. Assim, as BAL são importantes micro-organismos na indústria láctea, garantindo sabores e aromas aos derivados. Já a presença de NSLAB podem ser associados com defeitos em queijos e leites fermentados, sendo um problema na indústria beneficiadora.   Palavras-chave: Característica Sensorial. Leites Fermentados. Queijo. Textura.                       Abstract Fermented dairy products contain acid bacteria (BAL) naturally present or added to the dairy matrix as starter cultures (starters), contributing to aroma, texture, nutritional value and microbiological safety. Lactobacillus spp., Streptococcus spp., Lactococcus spp. and Leuconostoc spp. are used as starter dairy crops. As BAL it can be classified as mesophilic (ex: Lactococcus lactis) and thermophilic (ex: Streptococcus thermophilus), and agree with its fermentation metabolites in homofermentative (lactic acid) and heterofermentative (lactic acid, carbon dioxide, diacetyl and other flavorings). Among the BAL, there is a group of lactic bacteria that are not part of the dairy culture (non-initiating lactic acid bacteria - NSLAB) that originate from raw milk, the milking environment or the biofilm-forming industry. NSLAB is represented by heterofermentative species of mesophilic lactobacilli such as Lactobacillus casei spp., L. paracasei spp., L. rhamnosus spp. and L. plantarum spp., and also by Pediococcus spp., Leuconostoc spp. and Micrococcus spp. Termoduric NSLAB such as Bacillus spp. are also related. NSLAB in cheeses may help develop flavor and aroma, and they are also associated with defects in fermented cheeses and milks. Problems such as strange odors, bitter or very acidic taste, loss of viscosity, loss of color, establishment and gas training are associated with the presence and contamination by NSLAB. Thus,  BALs are important microorganisms in the dairy industry, contributing to the dairy flavors and aromas. The presence of NSLAB, on the other hand, can be associated with defects in fermented milk and cheese, being a problem in the processing industry.   Keywords: Cheese. Fermented Milk. Sensory Characteristic. Texture.


2016 ◽  
Vol 5 (1) ◽  
Author(s):  
Giusi Macaluso ◽  
Gerlando Fiorenza ◽  
Raimondo Gaglio ◽  
Isabella Mancuso ◽  
Maria Luisa Scatassa

Bacteriocins are antimicrobial proteins produced by bacteria that inhibit with a bactericidal or bacteriostatic mode of action, the growth of other bacteria. Many lactic acid bacteria (LAB) produce a high diversity of different bacteriocins. Bacteriocinogenic LAB are generally recognized as safe (GRAS) and useful to control the frequent development of pathogens and spoilage microorganisms; for this reason they are commonly used as starter cultures in food fermentations. In this study, the authors describe the results of a screening on 699 LAB isolated from wooden vat surfaces, raw milk and traditional Sicilian cheeses, for the production of bacteriocin-like inhibitory substances (BLIS), by comparing two alternative methods. The antagonistic activity of LAB and its proteinaceous nature were evaluated using the <em>spot on the lawn</em> and the <em>well-diffusion assay</em> and the sensitivity to proteolytic (proteinase K, protease B and trypsin), amylolytic (α-amylase) and lipolytic (lipase) enzymes. The indicator strains used were: <em>Listeria monocytogenes</em>, <em>Staphylococcus aureus</em>, <em>E. coli</em>, <em>Salmonella enteritidis</em>. A total of 223 strains (belonged to the species <em>Enterococcus</em> spp., <em>Lactobacillus</em> spp., <em>Pediococcus</em> spp., <em>Streptococcus</em> spp., <em>Leuconostoc</em> spp. and <em>Lactococcus lactis</em>) were found to inhibit the growth of <em>Listeria monocytogenes</em> by using the <em>spot on the lawn</em> method; only 37 of these were confirmed by using the well-diffusion assay. The direct addition of bacteriocin-producing cultures into dairy products can be a more practical and economic option for the improvement of the safety and quality of the final product.


2011 ◽  
Vol 63 (1) ◽  
pp. 11-20 ◽  
Author(s):  
Jelena Begovic ◽  
J.B. Brandsma ◽  
B. Jovcic ◽  
Maja Tolinacki ◽  
Katarina Veljovic ◽  
...  

Traditional Serbian cheese production has a long history and generates products with rich flavor profiles. To enable the industrial manufacture of these home-made Serbian cheeses, the lactic acid bacteria present in them needs to be characterized. Five fresh white cheeses made from raw cow?s milk without commercial starter cultures were collected from households on the mountain Stara Planina, Serbia. According to phenotypical and molecular analysis, 262 isolated Lwere found to belong to Lactococcus, Lactobacillus, Streptococcus, Leuconostoc or Enterococcus. The unique bacterial composition of each cheese indicates that the preservation of household industry is the way to maintain production of distinct cheeses.


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