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Food Analytical Methods

, Volume 12, Issue 11, pp 2555–2561 | Cite as

A New Method to Distinguish the Milk Adulteration with Neutralizers by Detection of Lactic Acid

  • Alessandra Aiello
  • Fabiana PizzolongoEmail author
  • Nadia Manzo
  • Raffaele Romano
Article
  • 56 Downloads

Abstract

A liquid chromatographic method based on determining of the amount of lactic acid was developed to detect milk adulteration with neutralizers. The developed method can be applied to milk with pH values within the regular range of 6.5–6.7 that is suspected of being neutralised. Determination of lactic acid was carried out in milk acidified with lactic acid and neutralised with sodium hydroxide to simulate the adulteration. The validation parameters showed high linearity (R2 > 0.99), good precision (relative standard deviation ≤ 0.123%) and high sensibility (limit of detection 0.1 mg/L and limit of quantification 1 mg/L). The proposed method was applied to bacterially acidified and subsequently neutralised milk and detected a content of lactic acid of approximately 40 mg/100 mL in milk slightly acidified to pH 6.4. The developed method is simple, fast, precise and suitable for detecting the addition of hydroxides in sour milk.

In parallel, the sodium content was determined in the same sodium hydroxide neutralised samples, but the addition of a small amount of this alkali does not affect the natural variation of sodium in milk.

Keywords

Milk adulteration Sodium hydroxide Lactic acid Neutralizers 

Notes

Compliance with Ethical Standards

Conflict of Interest

Alessandra Aiello declares that she has no conflict of interest. Fabiana Pizzolongo declares that she has no conflict of interest. Nadia Manzo declares that she has no conflict of interest. Raffaele Romano declares that he has no conflict of interest.

Ethical Approval

This article does not contain any studies with human participants or animals performed by any of the authors.

Informed Consent

Not applicable.

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Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Department of Agricultural SciencesUniversity of Naples Federico IIPorticiItaly

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