Europaisches Patentamt 295 © J) European Patent Office © Publication number: 0 359 A2 Office europeen des brevets EUROPEAN PATENT APPLICATION © Application number: 89201832.6 © int. Cl.5: A23C 19/032 © Date of filing: 10.07.89 © Priority: 22.07.88 NL 8801861 © Applicant: NEDERLANDS INSTITUUT VOOR ZUIVELONDERZOEK © Date of publication of application: Kernhemseweg 2 P.O. Box 20 21.03.90 Bulletin 90/12 NL-6710 ZB Ede (Gld)(NL) © Designated Contracting States: © Inventor: Exterkate, Fredericus Antonius BE DE FR NL Spinestraat 23 NL-6544 WE Nijmegen(NL) Inventor: De Veer, Gerardus Johanna Christina Maria Zomerdijk 57 NL-5391 BV Nuland(NL) © Representative: de Bruijn, Leendert C. et al Nederlandsch Octrooibureau Scheveningseweg 82 P.O. Box 29720 NL-2502 LS 's-Gravenhage(NL) (sj) Method for the preparation of cheese. © A method is provided for producing cheese us- ing a particular culture of a mesophilic starter and a mixed culture of thermophilic lactic acid bacteria. The mixed thermophilic culture, denoted as APS13, has a stable composition upon culturing. The cheese produced by this method is of the hard or semi-hard type and has a novel and interesting flavour profile, which is developed already at an early stage of ripening. < IT) C5 CM O) Lf> CO LU Xerox Copy Centre I =P 0 359 295 A2 Method for the preparation of cheese The invention relates to a method for the prep- consistency, the structure and the aroma of the aration of cheese in which both mesophilic and cheese as a consequence of too high an acidifica- thermophilic bacteria are used. tion activity. Specifically, the shortcoming termed Each type of cheese has a number of char- "bitter" is noted as one of the negative conse- acteristics, such as consistency, structure, degree 5 quences. Attempts have been made to prevent the of eye formation and aroma (smell and flavour). said adverse effects by selectively inactivating the Said characteristics are dependent on, inter alia, acid-forming power of the cells of the bacterial the method of preparation and the nature of the strain (or strains) to be added by subjecting these additives. In the case of the preparation of matured cells to a special pre-treatment such as "freeze cheese, the bacteria added to the milk to be pro- 10 shock" or "thermo shock". On the other hand it is cessed play an essential role. In the first place, attempted to make use of (lac-) mutants which are under the influence of the starter culture consisting non-acidifying in milk. In this case different difficul- of lactic acid bacteria, the necessary fall in pH is ties are encountered which are to be ascribed to an achieved as a consequence of the conversion of incomplete proteolytic system of the mutant. De- lactose to lactic acid. This fall in pH has a great 75 spite the great increase in the number of cells (12- influence on the consistency of the cheese. More- 15-fold) in the cheese, a very slight effect on the over, the lactic acid bacteria to a very great extent proteolysis and thus an only moderate effect on the influence the cheese ripening process by the ripening is detected (Austr. J. Dairy Technol. 38 breakdown of substances such as protein and citric (1983) 55-58). acid with the formation of, inter alia, aroma sub- 20 In EP-0 078 813 a method is described for stances. Types of cheese for which cheese ripen- giving more taste to cheese with an appreciably ing is mainly dependent on the starter used are, for lowered fat content, in which taste development is example, Gouda, Edam and Cheddar cheese. slow and weak, by separately adding a few cultures In the preparation of other types, yet further of thermophilic lactic acid bacteria in addition to microbiological systems are used in addition to the 25 the customary starter and, in a later stage, after starter consisting of lactic acid bacteria in order to draining off some of the whey, adding a quantity of form the aroma characteristic for these types of salt water. In accordance with this method cheeses cheese: surface mould (for example Brie and Cam- of a certain type such as Cheddar or Edam with a embert), surface bacteria (Limburger, Romadur) or greatly reduced fat content nevertheless acquire internal mould (Roquefort). The addition of pro- 30 the desired taste. In this case also there is appar- pionic acid bacteria which are activated by storing ently some form of accelerated ripening. A prac- the cneese for some time at a somewhat higher tical drawback of this method for generating the temperature is also known (Emmentaler, Maasdam- flavour belonging to the original type of cheese is mer). With most other types of cheese, a specific that the various strains all have to be cultured conversion which contributes to the aroma develop- 35 separately in order to prevent the irrevocable shift ment is stimulated by added enzymes, such as an in the composition of the whole during growth of intensified fat splitting by lipases in the case of the mixture. Another disadvantage of this method is some types of Italian cheese. that it is directed solely to flavour development in Now it is known to add, in addition to the low-fat cheese. starter bacteria which must effect the desired acidi- 40 It has now been found that by using a particu- fication, yet further lactic acid bacteria which have lar mixed culture as the culture of thermophilic no or little influence on the course of acidification bacteria the said drawbacks can be avoided. but which are able to intensify the flavour of the With the method according to the invention, in product. Thus, the addition of extra lactic acid addition to the starter customary for a specific type bacteria in addition to the customary starter has 45 of cheese, a special mixed culture APS13, consist- been carried out in the framework of an investiga- ing of various strains of thermophilic lactic acid tion into the possibility of accelerating cheese rip- bacteria, is added. This mixture of lactobacilli and ening, with the aim of causing the aroma char- streptococci has been deposited under No. CBS acteristic of a specific type of cheese to develop in 483.86 with the Centraal Bureau voor Schimmelcul- an earlier stage of ripening, without changing this 50 tures (Central Office for Mould Cultures), Baarn. At aroma (Neth. Milk Dairy J. 15 (1961) 151-164). It the preparation temperatures customary for the has been found that relatively high concentrations preparation of cheese with the aid of a mesophilic of cells are necessary for this accelerated ripening: starter, the course of acidification is determined by at least a 5-fold increase. The addition of extra the (mesophilic) starter even when the said ther- lactic bacteria has a highly adverse effect on the mophilic culture has been added. Furthermore, the 2 3 =P 0 359 295 A2 acidifying power of a APS13 culture can be re- susceptible to the shortcoming late blowing : the duced further by adjusting the culturing process. mixed culture is found to suppress to a great "Mesophilic" and "thermophilic" are concepts extent the undesired butyric acid bacterial fermen- which are not always defined in the same way. In tation which leads to the said shortcoming. the present description "mesophilic" is used to 5 Another unexpected aspect of the use of indicate lactic acid bacteria which exhibit an opti- APS13 is that despite the presence of a relatively mum growth at below 33 *C; the "thermophilic" high number of thermophilic lactobacilli the shor- mixture APS13 exhibits an optimum growth at tcoming "pink" does not arise. It is known that above 40 C. many strains of thermophilic lactobacilli can cause In contrast to the known methods described 70 an objectionable discoloration of the cheese above for the use of mesophilic and thermophilic (Bottazzi and Coradini, Sci.Tec.Latt.-cas. 17 (1966) lactic bacteria, the use of APS13 is found to effect 384; Shannon and Olson, J. Dairy Sci. 52 (1969) a drastic change in the flavour of the product, 1678). compared with that of the same type of cheese It is desirable to culture the APSi3 as a mix- which has been prepared without the addition of 15 ture; the monocultures derived from the mixed cul- APS13. A panel for sensory evaluation, practised in ture are separately found to grow poorly in milk. analytical testing and particularly in establishing Moreover, of course, the culture and storage proce- flavour profiles, established that the use of APS13 dures would have to be adapted for each monocul- leads to a flavour profile which is completely dif- ture, which is a drawback for large-scale use. ferent from that of, for example, Gouda cheese, but 20 The mixture can be cultured with or without pH also from that of Emmentaler or other types for control; preferably, however, the thermophilic cul- which thermophilic bacteria are used in the prep- ture is grown in milk at a constant pH value. In aration. The combination of the following flavour either case it is preferred to maintain the culture in elements is characteristic: a condition wherein little or no formation of lactic - slightly fruity/ester-like 25 acid occurs, for some time. - a sweet element which clearly differs from the The technique of culturing at constant pH by "sweet/ propionic acid-like" touch for Emmentaler neutralizing the lactic acid formed is known to and Maasdammer those skilled in the art. Preferably, a pH value - piquant between 5.5 and 6.0 is chosen; at each value within - bouillon-like 30 this range an advantageous ratio between the num- - somewhat nutty bers of lactobacilli and streptococci is obtained It is striking that the characteristic flavour is not such that the lactobacilli greatly predominate.