T 1632/06 (Natamycin stabilisation/DSM) 02-09-2009

1. The appeal is admissible.

2. Admissibility of opposition 1

2.1 The date of publication and mention of the grant of the patent in suit was 10 March 2004. Hence the period for filing an opposition ran out before the EPC 2000 came into force in 2007. The admissibility of opposition 1 thus is to be assessed under the EPC 1973.

2.2 The conditions under which an opposition is to be rejected as inadmissible are laid down in Rule 56 EPC 1973.

2.2.1 Rule 56(1) EPC 1973 states that an opposition is inadmissible if it does not comply with the provisions of Article 99(1), Rule 1(1) and Rule 55(c) EPC 1973, unless these deficiencies have been remedied within the opposition period.

2.2.2 The Appellant deemed opposition 1 to be inadmissible as it had not been signed in the name of the opponent, and as the address of opponent 1 contained a wrong postal code (see point VIII above). These are not deficiencies under Article 99(1), Rule 1(1) and Rule 55(c) EPC 1973, so that Rule 56(1) EPC 1973 does not apply to the present case.

2.2.3 Rule 56(2) EPC 1973 states that an opposition is also inadmissible if it does not comply with other provisions of the EPC and the opponent has not remedied the respective deficiency within the time limit set by the opposition division. The deficiencies of opposition 1 mentioned under point 2.2.2 above may be subsumed under Rule 55(a) EPC 1973 (as to the address of the opponent) and Rule 36(3) EPC 1973 (as to the signature). Consequently, Rule 56(2) EPC 1973 applies to these deficiencies.

Hence, the opposition division had to set a time limit to remedy these deficiencies. Consequently, it had also the power to extend this time limit or to set a new time limit whenever deemed appropriate.

In the protocol of the telephone conversation dated 04 March 2005, the formalities officer of the opposition division agreed to set a new time limit to remedy the deficiencies. Under cover of the telefax received on 08 March 2005, opponent 1 remedied the deficiencies by sending a new opposition form 2300 in which the correct postal code was indicated and which was duly signed by Mr Visschedijk. In the letter dated 07 March 2005 enclosed with said telefax, opponent 1 confirmed that Mr Visschedijk was authorised to sign on its behalf. Therefore, all the deficiencies were remedied before the opposition division had set a new time limit, namely "in good time" as required in Rule 56(2) EPC 1973.

2.3 The Board is not aware of any other deficiencies of opposition 1 which could render it inadmissible. Hence, it decided that opposition 1 is admissible.

3. Documents (D16) to (D24), (D27) and (D27a)

3.1 Respondent 2 enclosed documents (D16) to (D24) with its letter dated 13 August 2007. This letter was received by the EPO on 16 August 2007, and thus within the time limit to respond to the statement setting out the grounds of appeal of four months set by the Board in the communication dated 16 February 2007, extended for another two months as confirmed by the communication dated 29 May 2007.

A response to the statement setting out the grounds of appeal filed within the time limit set by the board - including any documents enclosed - generally forms part of the basis of the appeal proceedings (see Article 12(1)(b) and (4) of the Rules of Procedure of the Boards of Appeal; Supplement to OJ EPO 1/2009, 41).

In the present case, the Board saw no reason to deviate from this general practice as documents (D16) to (D24) are short and mostly are to illustrate the common general knowledge. Therefore, the Board admitted these documents into the proceedings.

3.2 Respondent 2 enclosed documents (D27) and (D27a) with his letter dated 31 July 2009. These documents disclose the use of polyvinyl acetate emulsions as thickeners. Therefore they may be regarded as being filed in response to the argument of the Appellant that polyvinyl acetate will not necessarily form an emulsion, first raised in its letter dated 02 July 2009 (see page 4 of said letter, the fourth and fifth paragraph under point 6).

Therefore, documents (D27) and (D27a) were considered not to be late-filed. Hence, there was no basis for not admitting these documents.

Main Request and Auxiliary Request 1

4. Novelty of the subject-matter of claim 13 of the Main Request and claim 1 of Auxiliary Request 1

Document (D7) discloses in example 1 blends of natamycin, calcium propionate and/or calcium acetate which were incorporated into an aqueous emulsion of polyvinyl acetate to form a cheese-coating composition, the pH value of which was adjusted to 4.0, "When necessary", by adding lactic acid (see page 4, lines 40-46). The concentration of the components of the respective cheese-coating compositions is listed in Table 1 on page 5.

The words "When necessary" clearly mean that lactic acid was added whenever the cheese-coating composition had a pH value of more than 4.0, namely in case it was more basic. This provision would not have been mentioned in the document if lactic acid was not added in at least one case, namely at least to that of the compositions 3 to 8 which is most basic. These most basic compositions are compositions 7 and 8 since they contain the slightly basic salts calcium acetate and calcium propionate in the highest concentrations. Therefore, composition 8 of example 1 - which contains natamycin whereas composition 7 does not - must have been adjusted to a pH value of 4.0 by means of lactic acid. Composition 8 thus discloses all the components of the composition to be used in the method of claim 13 of the Main Request and claim 1 of Auxiliary Request 1. The coating composition 8 is stable and the natamycin contained therein is active over a long period of time (see (D7), figure 2 and page 5, lines 31-43). Hence, document (D7) discloses all the features of claim 13 of the Main Request and claim 1 of Auxiliary Request 1, so that their subject-matter is not novel.

Since the Board can only decide on a request as a whole, the Main Request and Auxiliary Request 1 are rejected.

Auxiliary Requests 2 and 3

5. Novelty

The sole claims of these requests require that the anti-oxidation agent (and/or chelating agent) be used "for preventing deactivation of said natamycin" (see points VII(b) and (c) above).

The Respondents held the subject-matter of the claims of these requests not to be novel in view of document (D12).

In example 1f of this document, ascorbic acid is used. The Respondents argued that it was used to adjust the pH to a certain value which stabilises the activity of natamycin. However, in said example, the pH value "was adjusted to 4 by means of ... sodium hydroxide." (see column 7, lines 9-11). That means that ascorbic acid was not used in order to adjust the pH value. Nor does document (D12) disclose that ascorbic acid might prevent deactivation of natamycin in any other way. Moreover, the Board is not aware of any other prior art document disclosing the subject-matter of the sole claims of Auxiliary Requests 2 and 3. Therefore, the subject-matter of these claims is novel.

6. Inventive step

6.1 The closest prior art

The closest state of the art is normally a prior art document disclosing subject-matter with the same objectives as the claimed invention and having the most relevant technical features in common.

The objective of the subject-matter of the sole claims of Auxiliary Requests 2 and 3 was to prevent deactivation of natamycin in a polymer emulsion (see page 3, lines 11-18 of the application as filed.

Document (D7) is not concerned with the stability of natamycin except that it mentions in the discussion of the prior art that natamycin "is relatively unstable at low pH" (see page 2, lines 51-52).

Document (D12) relates "to chemically, physically and microbially stable concentrated suspensions of ... natamycin" (see column 1, lines 1-3) which may contain polyvinylacetate (see claim 5).

Therefore, it is rather document (D12) that is to be considered as representing the closest prior art.

Document (D12) discloses stable concentrated suspensions of natamycin useful for preparing liquid compositions for treating cheeses, sausages and agricultural products (see column 1, lines 1-9, and column 2, lines 49-56). The stability of the suspensions is increased to more than two weeks by keeping the pH within a range of from 3 to 6 and by adding a thickener (see column 3, lines 1-15).

6.2 The problem to be solved

The problem addressed in the application as originally filed was to prevent the deactivation of natamycin in an aqueous medium containing an emulsion polymer (see page 1, lines 27-29, and page 3, lines 12-22).

This problem is solved (see Table 1 on page 7 of the patent in suit (not according to the invention) as compared to Tables 2-6 on pages 8 and 9 (where an anti-oxidant (ascorbic acid) or EDTA (salt) was employed)).

6.3 Obviousness of the solution

6.3.1 The inactivation of natamycin in aqueous media is mentioned in document (D12) (see column 2, lines 20-22 and 43-45). There was no reason to believe that the person skilled in the art would think that this problem did not occur in the presence of polymer emulsions. Hence, posing this problem cannot contribute to the presence of an inventive step.

6.3.2 The person skilled in the art trying to stabilize natamycin in these compositions would have consulted document (D3), as this general article on natamycin deals with the stability of natamycin in chapter 5.

In particular, this document mentions that the inactivation of natamycin by peroxides or oxygen be prevented by anti-oxidants, such as ascorbic acid (see the first paragraph on page 544).

Therefore, the person skilled in the art was aware of the fact that the ascorbic acid used in example 1f of document (D12) did in fact prevent the natamycin from being deactivated. On the other hand it was obvious to the person skilled in the art to add anti-oxidants in order to stabilise natamycin against degradation in a composition containing the same.

6.3.3 The Board agrees with the Appellant in that document (D12) does not directly and unambiguously disclose compositions to which a polymer emulsion has been added. This is due to the fact that this document is directed to concentrated aqueous stock suspensions of natamycin (see column 2, lines 49-56).

On the one hand the Appellant did not provide any evidence that this feature contributed to the solution of the problem posed, so that it might not to be taken into account when assessing inventive step (see T 37/82, OJ EPO 1984, 71, point 3 of the reasons).

On the other hand, the addition of the polymer emulsion might be linked to the use of the respective compositions as cheese-coatings (see page 5, lines 17-20 of the application as filed), namely to a different problem. Document (D12) also discloses that the stock suspensions disclosed are "very useful ... for the large scale production of coating emulsions for the treatment of cheeses." (see column 6, lines 25-29; see also column 3, lines 20-24). The only information in document (D12) as to the additional components of cheese-coating compositions is found in the section discussing the prior art, namely in column 1, lines 17-20: "Cheeses are treated by immersion in a suspension of natamycin in water or covered by an emulsion of a polymer (mostly polyvinyl acetate) in water containing natamycin." If the person skilled in the art wanted to produce cheese-coating compositions from the concentrated stock suspension disclosed in document (D12) it was thus most obvious to dilute the stock suspension with a polymer emulsion.

6.3.4 Therefore, it was obvious to the person skilled in the art who was to provide a cheese-coating composition and to prevent the natamycin contained therein from deactivation, to solve these problems by

- diluting the concentrated stock suspensions disclosed in document (D12) with a polymer emulsion; and by

- using an anti-oxidation agent.

Consequently, the subject-matter of the sole claims of Auxiliary Requests 2 and 3 does not involve an inventive step.

7. To sum up, the subject-matter of claim 13 of the Main Request and that of claim 1 of Auxiliary Request 1 lack novelty, while the subject-matter of the sole claims of Auxiliary Requests 2 and 3 is not inventive. The Appellant did not file any additional auxiliary requests.