Dear Rachid Aboutayeb,

to remove polyphenols, OC (olive cake) may be first defattened with n-hexane and then extracted with ethanol, OWW (olive mill wastewater) may also be first defattened with n-hexane and then extracted with ethyl acetate by liquid-liquid extraction. See the full procedure here:

Article Olive Mill Waste Extracts: Polyphenols Content, Antioxidant,...

Wishing you best of success,

Johannes

You may adjust first of all the C/N ratio to 30 by adding straw based sheep manure or sheep manure only with bulking agent like sawdust. Formula of C/N ratio is available in the attached paper. Continuous turning is crucial for microorganisms respiration and thermophile phase stability. If olive mill waste still contain oil then it would be better to let ripe more and by the way drain excess of oil. Composting with oil excess is not recommended since oil is not absorbed by bulking agent and remains on the top thus prevent respiration and microorganisms growth and development.

Dear carole,

Many thanks for your answer.

Best regards.

Many thanks.

Dear Johannes,

Thank you for your reply.

Best regards.

Dear Khalid,

Many thanks for your reply.

Best wishes.

Dear Rachid,

it is very nice of you that you thank each one of us. Keep up your good ways no matter what. :-)

Wishing you successful scientific research,

Johannes

Dear Johannes,

I have an other question to ask you, how could method validation contribute to enhance food safety?

Dear Rachid,

method validation, in general, may prove by comparison of selected performance parameters measured during the validation process to certain performance criteria, e.g. legal criteria for the respective food or feed sector, that the method is, in principle, fit for the purpose. However, it must then be proven in routine by on-going quality control, that the required standards and/or criteria are being met with. This means, that method performance is monitored in routine by checking certain QC parameters, often those previously chosen during method validation.

In the case of polyphenols in olive mill waste, one criteria may be that polyphenols must be removed from the waste to a certain extent (e.g. as allowed by legislation, or what is reasonable from a toxicological standpoint), so that only a certain residual concentration will remain in the waste. This requirement must then be checked periodically during routine extraction/processing. In other words, you check the efficiency of the extraction step which must ensure that the extracted waste is safe for whatever use or purpose.

Hope this helps,

Johannes

Dear Johannes,

Thank you for rapid reply, I'm very grateful.

Best regards.