Microbial Diversity in Dairy Products

For about one decade, studies of the microbial ecology of cheese have focused on explaining the relationship between microbial population succession (in terms of implantation/growth/colonization), enzyme production/activity (with reference to milk and rennet enzymes too, in addition to those of a microbial origin) and cheese texture, taste and flavor development. Great emphasis has been given to the importance of microbial diversity and the role of non-starter microorganisms. Nevertheless, there is scant information, both in terms of quality and quantity, to be used for total technological control/management of cheese quality, or for producing pasteurized milk cheese with flavor resembling raw milk cheese.

Therefore, given that molecular techniques can quantify both microbial species that can be encountered, targeting rRNA genes and their activity, and evaluating the expression of functional genes according to methods already applied to the study of natural environments (Saleh-Lakha, et al. 2005), it may be worth briefly recalling microorganisms and metabolic activities that are expected during the most important above-mentioned phases of cheese making.

In evaluating cheese milk quality, species- or biotype-specific DNA sequences can be targeted for detection of pathogenic microorganisms. Therefore, sequences of genes encoding for toxins can be used both to detect the producer's occurrence and ascertain the specific gene expression during milk cold-storage, ripening or partial skimming. During these pre-treatments, microbiological investigations should also deal with monitoring the effective growth of useful microflora in comparison with that of psychrotrophic flora regarded as spoilage agents. Of the latter, Pseudomonas spp., Alteromonas putrefaciens, Alcaligenes faecalis, Arthrobacter globiformis, Serratia spp., Enterobacter spp. and Flavobacterium spp. may be responsible for anti-technological activities: undesirable proteolytic and lipolytic activities, ammonia production, diacetyl mineralization and production of many off-flavors, like fruity, sweetish, fecal or putrid.

Within production of long-ripened cheese, the presence of the anaerobic sporeformer Clostridium tyrobutyricum - considered the causative agent of late blowing spoilage - can be verified in cheese-milk by species-specific PCR according to Klijn, et al. (1995a) or by PCR-DGGE (Cocolin, et al. 2004).

In studying microbial ecology during cheese manufacture, microorganisms need to be monitored with reference to their taxonomic and metabolic diversity to be consistent with technological protocol. Of course, mixed and more complex microflora must be expected in raw milk cheeses and when natural starter cultures are used. In these cases, in fact, the acidification process relies on the indigenous microflora, usually taxonomically complex. Considering the temperature ranges suitable for the various LAB groups, both thermophilic and mesophilic species can occur. The most important species of the microflora occurring during the manufacture of the main types of cheese are reported in Table 2.1.

Only residual amounts of lactose are generally available at the end of cheese manufacture. Thus, the initially dominant starter microorganisms responsible for acidification and flavor production from lactose and citrate during the first phase of cheese making are destined to progressively decrease from the phase of cheese ripening. Thereafter, depending on the cheese variety, secondary and/or adventitious microflora begin their growth, carrying out their activities. The latter involve both metabolites formerly produced by starter bacteria and the other constituents of cheese curd, like proteins and fat, generally transformed to a lesser extent within the first stage of cheese making. Moreover, they complement biochemical activities arising from residual milk plasmin, rennet enzymes and starter cell autolysis. However, secondary and adventitious microflora should not be regarded as agents of single specific processes, but as contributors to the overall complex transformations influencing the final cheese quality.

Milk proteins and lipid metabolism by dairy bacteria, yeast and molds will release key flavor molecules that will characterize each kind of cheese. Such compounds are the result of the diversity of the microrganisms and their activities during cheese ripening.

Microbial ecology of cheese, as well as of other fermented dairy products, can greatly benefit from molecular tools supporting identification of microbial species and strains occurring during the production processes, discriminating and quantifying

Taxon

Products

Starter Microorganisms (mainly responsible for production of lactic acid, ethanol, acetaldehyde and diacetyl)*

Lactococcus /actis subsp. /actis

Lactococcus lactis subsp. lactis biovar diacetylactis Lactococcus lactis subsp. cremoris

Streptococcus salivarius Streptococcus thennophilus

Streotococcus macédoniens Enterococcus faecium

Enterococcus faecal is

Enterococcus durons Leuconostoc lactis Leuconostoc mesenteroides subsp. mesenteroides

Vim **(l); Kefir (1); Cheddar (3); Edam-Gouda (4); Cottage cheese (6); Camembert (3); Brie (4);Blue-veined cheeses (3); Limburger and other surface-ripened cheeses (6); Artisanal Mozzarella (16); Water buffalo Mozzarella (8); Artisanal Emmenthal (9); Pecorino Sardo (9); Majorero (9); Fior di Latte di Agerola (10); Caciocavallo Silano (18); Canestrato Pugliese (22); Salers (25); Toma Piemontese (29); Fiore Sardo (30); Stilton (31); Ragusano (32)

Viili (1); Kefir (1); Blue-veined cheeses (3); Limburger and other surface-ripened cheeses (6); Water buffalo Mozzarella (8)

Viili** (1); Kefir (1); Cheddar (3); Edam-Gouda (4); Cottage cheese (6); Camembert (3); Brie (4);

Blue-veined cheeses (3); Limburger and other surface-ripened cheeses (6); Water buffalo Mozzarella (8); Artisanal Emmenthal (9); Pecorino Sardo (9); Majorero (9); Canestrato Pugliese (22); Toma Piemontese (29) Salers (25)

Kefir (1); Yogurt (2); Gorgonzola (4); Brie (4); Emmenthal (4); Artisanal Emmenthal (9); Mozzarella (4); Artisanal Mozzarella (16); Water buffalo Mozzarella (8); Fior di Latte di Agerola (10); Grana Padano (12); Parmigiano Reggiano (13); Pecorino Romano (14); Montasio (14); Provolone (14); Asiago (21); Scamorza Altamurana(23); Toma Piemontese (29); Ragusano (32) Kasseri (19); Asiago (20); Montasio (20); Scamorza Altamurana(23); Salers (25); Toma Piemontese (29) Artisanal Emmenthal (9); Water buffalo Mozzarella (8); Fior di Latte di Agerola (10); Pecorino Sardo (9); Majorero (9); Caciocavallo Silano (18); Canestrato Pugliese (22); Salers (25); Fiore Sardo (27); Toma Piemontese (29)

Artisanal Emmenthal (9); Artisanal Mozzarella (16); Water buffalo Mozzarella (8); Fior di Latte di Agerola (10); Pecorino Sardo (9); Majorero (9); Caciocavallo Silano (18); Canestrato Pugliese (22); Salers (25); Fiore Sardo (27); Toma Piemontese (29); Ragusano (32) Scamorza Altamurana(23); Fiore Sardo (27); Toma Piemontese (29) Water buffalo Mozzarella (8); Ragusano (32)

Artisanal Emmenthal (9); Artisanal Mozzarella (16); Water buffalo Mozzarella (8); Fior di Latte di Agerola (10);Pecorino Sardo (9); Majorero (9); Salers (25); Ragusano (32)

Taxon

Products

Leuconostoc mesenteroides subsp. dextranicum Leuconostoc mesenteroides subsp. cremoris Leuconostoc pseudomesenteroides Leuconostoc argentinum Leuconostoc gelidum Weissella hellenica Weissella paramesenteroides Weissella viridescens

Lactobacillus delbrueckii subsp. bulgaricus

Lactobacillus delbrueckii subsp. lactis

Lactobacillus helveticus

Lactobacillus casei Lactobacillus casei Lactobacillus casei Lactobacillus casei Lactobacillus casei Lactobacillus casei subsp. casei subsp. pseudoplantarum subsp. alactosus subsp. rhamnosus subsp. paracasei Lactobacillus paracasei Lactobacillus paracasei biovar Shirota Lactobacillus paracasei subsp. paracasei Lactobacillus plantarum

Lactobacillus kefir

Kéfir (1); Water buffalo Mozzarella (8)

Viili (1); Kéfir (1); Water buffalo Mozzarella (8)

Canestrato Pugliese (22); Ragusano (32) Fior di Latte di Agerola (10) Artisanal Mozzarella (17) Fior di Latte di Agerola (10) Scamorza Altamurana (23)

Yogurt (2); Gorgonzola (4); Emmenthal (4); Artisanal Emmenthal (9); Mozzarella (4); Fior di Latte di Agerola (10); Grana Padano (12); Parmigiano Reggiano (13); Pecorino Romano (14); Pecorino Sardo (9); Majorero (9); Caciocavallo Silano (18); Asiago (21); Ragusano (32) Kéfir (1); Emmenthal (4); Artisanal Emmenthal (9); Water buffalo Mozzarella (8); Grana Padano (12); Pecorino Romano (14); Pecorino Sardo (9); Majorero (9); Parmigiano Reggiano (13); Caciocavallo Silano (18); Scamorza Altamurana(23); Ragusano (32) Kéfir (1); Emmenthal (4); Artisanal Emmenthal (9); Mozzarella (4); Artisanal Mozzarella (17); Water buffalo Mozzarella (8); Fior di Latte di Agerola (10); Grana Padano (12); Parmigiano Reggiano (13); Pecorino Romano (14); Pecorino Sardo (9); Majorero (9); Montasio (14); Asiago (14); Provolone (14); Scamorza Altamurana(23) Caciocavallo Silano (18); Canestrato Pugliese (22); Fiore Sardo (30); Ragusano (32) Artisanal Mozzarella (17); Fior di Latte di Agerola (10) Water buffalo Mozzarella (8) Kéfir (1) Kéfir (1)

Scamorza Altamurana(23)

Caciocavallo Silano (18); Salers (25); Fiore Sardo (30) Yakult (2)

Fior di Latte di Agerola (10)

Artisanal Mozzarella (17); Water buffalo Mozzarella (8); Fior di Latte di Agerola (10); Caciocavallo Silano

(18); Canestrato Pugliese (22); Salers (25); Fiore Sardo (30); Ragusano (32) Kéfir (1)

Taxon

Products

Lactobacillus brevis Lactobacillus cellobiosus Lactobacillus fennentum

Kluyveromyces lactis

Kluyveromyces marxianus subsp. bulgaricus Kluyveromyces marxianus subsp. matxianus Saccharomyces florentinus Saccharomyces globosus Saccharomyces unisporus

Co-starter or adjuncts (typical Lactobacillus acidophilus Lactobacillus paracasei subsp. paracasei Lactobacillus paracasei biovar Shirota Lactobacillus rhamnosus Lactobacillus reuteri Bifidobacterium spp. Enterococcus faecium Enterococcus faecal is Pediococcus acidilactici Penicillium camemberti Penicillium roqueforti Geotrichum candidum Propionibacterium fruedenreichii subsp.

shennanii Brevibacterium linens

Kefir(1) Kefir(1)

Artisanal Emmenthal (9); Grana Padano (12); Artisanal Mozzarella (17); Caciocavallo Silano (18);

Scamorza Altamurana(23); Ragusano (32) Kefir(1) Kefir(1) Kefir(1) Kefir(1) Kefir(1) Kefir(1)

components of the secondary microflora of some products, often intentionally introduced)

Bio-Yogurt (2)

Bio-Yogurt (2)

Bio-Yogurt (2)

Bio-Yogurt (2)

Bio-Yogurt (2)

Bio-Yogurt (2)

Bio-Yogurt (2)

Bio-Yogurt (2)

Roquefort and other blue-veined cheeses (3); Gorgonzola (4); Stilton (9); Danish blue (9); Stilton (31) Viili (1); Brie (4); Limburger and other surface-ripened cheeses (6) Emmenthal and other Swiss type cheeses (4)

Camembert (3); Limburger and other surface-ripened cheeses (6); Smear ripened cheeses (9); Gubbeen

Taxon

Products

Streptococcus thennophilus Lactobacillus helveticus

Lactobacillus subsp. casei

Lactobacillus casei subsp. pseudoplantarum

Non-starter Microorganisms (generally

Lactococcus rafflnolactis Lactococcus gatyieae Streptococcus durans Streptococcus filant Streptococcus bovis Streptococcus uberis Streptococcus parauberis Streptococcus suis Streptococcus millieri Aerococcus viridans Enterococcus suphurans Enterococcus hirae Enterococcus faecalis Pediococcus acidilactici Pediococcus pentosaceus Lactobacillus casei

Lactobacillus casei subsp. casei Lactobacillus casei subsp. pseudoplantarum Lactobacillus paracasei

adventitious: poorly acidifying lactic acid bacteria, micrococci, corynebacteria, yeasts and molds)

Fior di Latte di Agerola (10)

Artisanal Mozzarella (16); Fior di Latte di Agerola (10); Salers (25); Toma Piemontese (29) Kefir (1) Kefir (1)

Artisanal Mozzarella (16); Scamorza Altamurana(23); Ragusano (32) Artisanal Mozzarella (16) Fior di Latte di Agerola (10)

Fior di Latte di Agerola (10); Toma Piemontese (29) Salers (25)

Artisanal Mozzarella (16) Artisanal Mozzarella (16); Ragusano (32) Ragusano (32) Stilton (31)

Parmigiano Reggiano (13); Ragusano (32) Cheddar (9); Salers (25)

Cheddar (6); Jarlberg (9); Norvegia (9); Herrgard (9); Greve (9); Gouda (9); Irish Cheddar (9); Parmigiano

Reggiano (13) Italian ewe's cheeses (33) Italian ewe's cheeses (33)

Jarlberg (9); Norvegia (9); Herrgard (9); Greve (9); Gouda (9); Kefalotyri (9); Tenerife goat's milk cheese (9); Majorero (9); Arzua (9); Armada (9); Serra da Estrela (9); (9); Casu Axedu (9); Fontina (9); Swiss type (9); British Cheddar (9); Irish Cheddar (9); Pecorino (15); Comté (24)

Taxon

Products

Lactobacillus paracasei subsp. paracasei Lactobacillus paracasei subsp. tolerans Lactobacillus rhamnosus

Lactobacillus plant arum

Lactobacih Lactobacih

Lactobacih Lactobacih

'lus paraplantarum Uus brevis

'lus fennentum 'lus cuiyatus

Lactobacillus helveticus Lactobacillus bifennentans Lactobacillus buchneri Lactobacillus parabuchneri Lactobacillus farciminis Lactobacillus kefir Lactobacillus graminis Lactobacillus sakei Lactobacillus homoiochii Lactobacillus maltaromicus Lactobacillus pentosus Lactobacillus gasseri Camobacterium divergens

Parmigiano Reggiano (13) Italian ewe's cheeses (33) Parmigiano Reggiano (13)

Jarlberg (9); Norvegia (9); Herrgard (9); Greve (9); Gouda (9); Cheddar (9); Grana Padano (12); Parmigiano Reggiano (13); Caciocavallo Silano (18); Comté (24); Fiore Sardo (30); Italian ewe's cheeses(33)

Cheddar (6); Feta (9); Teleme (9); Kefalotyri (9); Tenerife goat's milk cheese (9); Cabrales (9); Afuega'l Pitu (9); Majorero (9); Mahon (9); Arzua (9); Armada (9); Serra da Estrela (9); Casu Axedu (9); Fontina (9); Toma (9); Swiss type (9); Irish Cheddar (9); Pecorino (15); Stilton (31); Italian ewe's cheeses(33) Fiore Sardo (30)

Afuega'l Pitu (9); Majorero (9); Swiss type (9); British Cheddar (9); Irish Cheddar (9); Caciocavallo Silano

(18); Canestrato Pugliese (22); Italian ewe's cheeses (33) Majorero (9); Toma (9); British Cheddar (9); Italian ewe's cheeses (33)

British Cheddar (9); Irish Cheddar (9); Fior di Latte di Agerola (10); Caciocavallo Silano (18); Fiore Sardo

(30); Italian ewe's cheeses (33) British Cheddar (9) British Cheddar (9) British Cheddar (9) British Cheddar (9); Comté (24) British Cheddar (9) British Cheddar (9)

Fior di Latte di Agerola (10); Fiore Sardo (30)

Fior di Latte di Agerola (10); Caciocavallo Silano (18); Fiore Sardo (30) Fior di Latte di Agerola (10) Fior di Latte di Agerola (10)

Fior di Latte di Agerola (10); Canestrato Pugliese (22); Fiore Sardo (30); Italian ewe's cheeses (33) Scamorza Altamurana (23) Artisanal Mozzarella (16)

Taxon

Products

Camobacterium piscícola Brevibacterium imperiale Brevibacterium fuscum Brevibacterium oxyclans Brevibacterium helvolum Corynebacterium casei Corynebacterium ammoniagenes Corynebacterium betae Corynebacterium insidiosum Corynebacterium variabile Arthrobacter aril ait ensis Arthrobacter mysorens Arthrobacter citreus Arthrobacter globifonnis Arthrobacter nicotianae Microbacterium gubbeenense Agrococcus sp. nov Curtobacerium poinsettiae Microbacterium imperiale Rhodococcus fascians Caseobacter variabilis Macrococcus caseoliticus Micrococcus spp. Micrococcus Intens Micrococcus lylae Kocuria kristinae Kokuria roseus Staphylococcus epidennidis Staphylococcus equorum

Artisanal Mozzarella (16) Smear ripened cheeses (9) Smear ripened cheeses (9) Smear ripened cheeses (9) Smear ripened cheeses (9)

Milleens (11); Gubbeen (11); Durrus (11); Adrahan (11) Smear ripened cheeses *** (9) Smear ripened cheeses *** (9) Smear ripened cheeses *** (9)

Smear ripened cheeses *** (9); Milleens (11); Gubbeen (11) Milleens (11); Gubbeen (11); Durrus (11); Adrahan (11) Durrus (11)

Smear ripened cheeses *** (9) Smear ripened cheeses *** (9) Smear ripened cheeses *** (9) Gubbeen (11) Gubbeen (11)

Smear ripened cheeses *** (9) Smear ripened cheeses *** (9) Smear ripened cheeses *** (9) Smear ripened cheeses *** (9) Ragusano (32)

Limburger and other surface-ripened cheeses *** (6)

Durrus (11); Artisanal Mozzarella (16)

Smear ripened cheeses *** (9); Milleens (11); Adrahan (11); Stilton (31)

(continued)

Taxon

Products

Staphylococcus vitulus Staphylococcus xylosus Staphylococcus saprophyticus Staphylococcus carnosus Staphylococcus lentus Staphylococcus sciuri Halomonas venusta Saccharomyces cerevisiae Saccharomyces unisporus Candida utilis Debaiyomyces hansenii

Kluyveromyces lactis

Kluyveromyces marxianus Geotrichum candidum Yarrowia lipolytica

Brettanomyces spp. Dekkera anomala Candida spp. Candida zeylanoides Candida parapsilosis Candida silvae Candida intennedia Candida kefir Candida catanulata

Artisanal Mozzarella (16)

Salers (26)

Salers (26)

Roquefort (5); Camembert (7); Limburger and other surface-ripened cheeses *** (6); Smear ripened cheeses *** (9); Danish blue (9); Milleens (11); Gubbeen (11); Durrus (11); Adrahan (11); Water buffalo Mozzarella (8); Salers (26); Sardinian ewe's cheeses (28) Roquefort (5); Camembert (7); Water buffalo Mozzarella (8); Smear ripened cheeses *** (9); Salers (26);

Sardinian ewe's cheeses (28) Salers (26); Sardinian ewe's cheeses (28) Smear ripened cheeses *** (9); Sardinian ewe's cheeses (28)

Camembert (7) Limburger and other surface-ripened cheeses *** (6); Danish blue (9); Milleens (11);

Sardinian ewe's cheeses (28) Water buffalo Mozzarella (8) Sardinian ewe's cheeses (28)

Roquefort (5); Camembert (7); Limburger and other surface-ripened cheeses *** (6)

Salers (26)

Salers (26)

Salers (26)

Salers (26)

Kefir(1)

Sardinian ewe's cheeses (28)

Taxon

Products

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  • Karin
    What is the diversity for dairy products?
    7 years ago

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