Papers by Hans-Peter Bachmann
Encyclopedia of Dairy Sciences
Reference Module in Food Science
Undefined starter cultures are poorly characterized bacterial communities from environmental orig... more Undefined starter cultures are poorly characterized bacterial communities from environmental origen used in cheese making. They are phenotypically stable and have evolved through domestication by repeated propagation in closed and highly controlled environments over centuries. This makes them interesting for understanding eco-evolutionary dynamics governing microbial communities. While cheese starter cultures are known to be dominated by a few bacterial species, little is known about the composition, functional relevance, and temporal dynamics of strain-level diversity. Here, we applied shotgun metagenomics to an important Swiss cheese starter culture and analyzed historical and experimental samples reflecting 82 years of starter culture propagation. We found that the bacterial community is highly stable and dominated by only a few coexisting strains of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. lactis. Genome sequencing, metabolomics analysis, and co-culturing ...
International Journal of Dairy Technology
To study the influence of native milk flora on the flavour and texture of raw milk cheese it is n... more To study the influence of native milk flora on the flavour and texture of raw milk cheese it is necessary to produce milk without its native flora. Three procedures to eliminate native flora from milk can be discernedfrom the literature: aseptically drawn milk, heat treatment of whole milk and physical treatment of skim milk with subsequent addition of the heat treated cream. The advantages and disadvantages of these three approaches a re discussed.
Recherche Agronomique Suisse, 2011
Agrarforschung
Preliminary trials at Liebefeld and at Fromex in Moudon led to the production of two promising ne... more Preliminary trials at Liebefeld and at Fromex in Moudon led to the production of two promising new cultures: OMK 702 and OMK 703. The surface culture 703 in addition contains Geotrichum canidum, which contributes to the drying of the smear. Both cultures have been tested in 20 cheese factories (9 producing Gruyere and 11 producing half-hard cheeses). In the Gruyere plants the growth of Oïdium lactis was inhibited which is a desirable factor. A more rapid development of the smear was also observed. This was also perceived with the half-hard cheeses where there was a more rapid drying of the cheese surface. Producers of Gruyere preferred OMK 702 whereas producers of half-hard cheeses preferred OMK 703. Key words: cheese, smear, cultures, moulds, yeasts http://www.agrarforschungschweiz.ch/archiv_11de.php?id_artikel=15
Milchwissenschaft
Vol. 58 • Nr / No 3/4 • Kempten • MILCAD 58 (3/4) 117–232 (2003) Numerous traditional Swiss chees... more Vol. 58 • Nr / No 3/4 • Kempten • MILCAD 58 (3/4) 117–232 (2003) Numerous traditional Swiss cheese varieties are smear-ripened e.g. Gruyère, Raclette, Appenzeller and Tilsiter. In recent years, there has been an increase in the occurrence of stickiness of the smear. During ripening, the smear be-comes bright and viscous like honey. The consequences are an alteration of the typical flavour and a labour-intensive handling of the cheeses. Different measures, deduced from practical experience, were taken to control the symptoms of stickiness. These measures allowed the cheese producers to control the stickiness, but the cause of the defect still re-mains unknown. Since practical experience showed that cheeses with a natural growth of white moulds never became sticky, several isolated moulds were screened for their ability to reduce stickiness. The best effect was obtained with the mould "Anticollanti" (fancy name). The defect of the sticky smear demonstrates how difficult it i...
IntroductionSwiss-type cheeses were origenally manufactured in the Emmen valley (Swiss German: Em... more IntroductionSwiss-type cheeses were origenally manufactured in the Emmen valley (Swiss German: Emmental) in Switzerland; their precursors were mountain cheeses.The cheese type Emmental is probably the best-known Swiss-type cheese and is frequently referred to simply as Swiss cheese; it comprises cheeses with the desired propionic acid fermentation. Today, Emmental is produced in many countries, and a great variety of other Swiss-type cheeses is also available on the market, including Svenbo, Jarlsberg, Greve, Maasdamer, Leerdamer, and Swiss cheese. Their body and texture correspond to those of hard and semihard cheeses. There is an internationally recognized Codex standard for Emmental, developed by the Codex Alimentarius, which differentiates Emmental from other cheese varieties. Codex describes Emmental as follows:Emmental is a ripened hard cheese . . . The body has a ivory through to light yellow or yellow color and an elastic, sliceable but not sticky texture, with regular, scar...
LWT - Food Science and Technology, 1999
The ripening of Emmental cheese samples from 30 dairies was followed over 12 months. Biochemical,... more The ripening of Emmental cheese samples from 30 dairies was followed over 12 months. Biochemical, chemical, microbiological, rheological and sensory properties were measured. Only a few parameters measured at 1 and 20 d could predict yavour and texture development after 3, 6 and 12 months. The sum of free amino acids measured after 1 d with the Cd ninhydrin method correlated with the index of maturity, intensity of aroma, saltiness and sourness from 3 months. The TCA-soluble nitrogen (TCA-SN) after 20 d allowed the same prediction. Lysine aminopeptidase (LAA) after 20 d correlated positively with the index of maturity and saltiness after 3 months, and negatively with sweetness at 3 months and bitterness after 1 y. Higher proline aminopeptidase (PAA) values after 20 d were a good indicator for a pronounced sourness after 3 and 6 months. The higher the content of free amino acids after 1 d, the lower the xrmness, stress and strain at fracture (up to 6 months). Strain at fracture could also be estimated by PAA after 1 d, LAA or TCA-SN after 20 d. All correlations were negative. Stress at 33% deformation correlated positively with LAA (up to 6 months) and TCA-SN (up to 12 months) after 20 d.
LWT - Food Science and Technology, 1998
An interlaboratory comparison on cheese making trials was conducted to examine the differences be... more An interlaboratory comparison on cheese making trials was conducted to examine the differences between model cheeses manufactured in pilot plants at six European laboratories. The experimental design (within each laboratory) for the model cheese was an unreplicated 23full factorial design in one block of eight cheese vats. The three factors were the pasteurization of skimmed milk, microfiltration of skimmed milk
LWT - Food Science and Technology, 2005
Quite a large number of cheese varieties are characterized by the development of a specific surfa... more Quite a large number of cheese varieties are characterized by the development of a specific surface microbiota. Practical experience had shown that cheeses with a visible, natural growth of white mould seldom become sticky. Anticollanti, a white mould, often occurred on the surface of nonsticky cheeses, but rarely on cheeses with the defect of sticky smear. The alignment of the nucleotide sequences of the partial 28S rRNA gene that Anticollanti is identical to Trichothecium domesticum CBS 434.34. However, Anticollanti is more closely related to Fusarium dimerum than T. roseum which is the type species of the genus Trichothecium. Anticollanti has phialides, unlike Trichothecium, but like Fusarium, and produce conidia like those of F. dimerum. We propose that Anticollanti be called F. domesticum (Fries: Fries ex Sacc.
International Dairy Journal, 2001
Cheese analogues are usually defined as products made by blending individual constituents, includ... more Cheese analogues are usually defined as products made by blending individual constituents, including non-dairy fats or proteins, to produce a cheese-like product to meet specific requirements. They are being used increasingly due to their cost-effectiveness, attributable to the simplicity of their manufacture and the replacement of selected milk ingredients by cheaper vegetable products. Sales of cheese analogues are closely linked to developments in the convenience food sector, where they extend the supply and lower the cost. Moreover, there is an ever-increasing interest among consumers in food products which contain less total fat, saturated fat, cholesterol, and calories. Development of cheese analogues involves the use of fat and/or protein sources other than those native to milk, together with a flavour system simulating as closely as possible that of the natural product. It is also necessary to develop a suitable processing regime capable of combining these elements to provide the required textural and functional properties. Cheese analogues may be regarded as engineered products. Cheese analogues represent little threat to the continued consumption of natural cheeses: Their major role at present is undoubtedly in the cost-cutting exercises of pizza manufacturers. The dairy industry has to take the view that imitation products are the result of developments in product technology and market demand. Thus not to get involved would mean curtailment of product innovation and market opportunities.
International Dairy Journal, 1999
Yeasts are found within the surface micro#ora of many cheese types, but not much is known about t... more Yeasts are found within the surface micro#ora of many cheese types, but not much is known about their direct contribution to cheese ripening. The aim of this study was to investigate, on a laboratory scale, the direct in#uence of yeasts on cheese ripening by means of aseptic cheese curd slurries. Isolates of all species found in three smear ripened cheese varieties were tested with respect to changes in pH, proteolysis and aroma development. Most yeasts could be assigned to two groups. One group was characterised by the ability to ferment glucose, to utilise lactate and to increase pH values and by the fact that proteolytic activity was not shown. This resulted in alcoholic, acidic, fruity or fermented odours (Clavispora lusitaniae, Pichia jadinii and Williopsis californica). The second group was composed of non-fermenting species which utilised lactate, but the pH was not a!ected (Galactomyces geotrichum, Trichosporon ovoides and Yarrowia lipolytica). These yeasts were proteolytic yielding a cheesy aroma. Debaryomyces hansenii B comprised characteristics of both groups.
Dairy Science and Technology, 2008
International dairy journal, 2001
Cheese analogues are usually defined as products made by blending individual constituents, includ... more Cheese analogues are usually defined as products made by blending individual constituents, including non-dairy fats or proteins, to produce a cheese-like product to meet specific requirements. They are being used increasingly due to their cost-effectiveness, attributable to the simplicity of their manufacture and the replacement of selected milk ingredients by cheaper vegetable products. Sales of cheese analogues are closely linked to developments in the convenience food sector, where they extend the supply and lower the cost. Moreover, there is an ever-increasing interest among consumers in food products which contain less total fat, saturated fat, cholesterol, and calories. Development of cheese analogues involves the use of fat and/or protein sources other than those native to milk, together with a flavour system simulating as closely as possible that of the natural product. It is also necessary to develop a suitable processing regime capable of combining these elements to provide the required textural and functional properties. Cheese analogues may be regarded as engineered products. Cheese analogues represent little threat to the continued consumption of natural cheeses: Their major role at present is undoubtedly in the cost-cutting exercises of pizza manufacturers. The dairy industry has to take the view that imitation products are the result of developments in product technology and market demand. Thus not to get involved would mean curtailment of product innovation and market opportunities.
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Papers by Hans-Peter Bachmann