Fresh 1660 nm. The chemometric tools like Principle

Fresh milk has a shelf life of a few hours at
refrigerated temperature of less than 4?, due to increase the shelf life of
milk and saving the costs of cooling, milk adulterated with chemicals such as
penicillin, formalin and hydrogen peroxide. These additives can increase the
shelf life of milk without cooling and these additions have the potential to
cause serious health-related problems for human and also affect on processing
of milk in dairy industry. Several analytical techniques can be used to detect
adulteration but they often require time-consuming, sample preparation,
expensive laboratory equipment, and highly skilled personnel. We employed a
portable Near Infrared spectroscopy (NIR) combined with multivariate analysis
was developed to detect adulteration as well as to quantify the level of
hydrogen peroxide in cow milk adulterated. In this study fresh cow milk samples
were collected from three farms surrounding Beijing district and five farms in
Hebei province in China were investigated. Those fresh cow milk samples were
then adulterated with hydrogen peroxide at ten different percentage levels: 0.5%,
0.7%, 0.9%, 1%, 1.5%, 1.7%, 1.9%, 2%, 2.5%, and 2.7% of hydrogen peroxide. All
samples were scanned using NIR spectroscopy (JDSU, California, USA). The
MicroNIR 1700 spectrometer analyses the wavelength region is 870 – 1660 nm. The
chemometric tools like Principle component analysis (PCA), partial least
discriminant analysis (PLS-DA) and partial least squares regression (PLS) was
applied for statistical analysis of the obtained NIR spectral data. To check
the discrimination between the pure and hydrogen peroxide adulterated milk
samples, PLS-DA model was used. For PLSDA model the R-square value obtained was
0.989 with 0.081 RMSE (Root mean square error). Furthermore, PLS regression
model was also built to quantify the levels hydrogen peroxide adulterant in cow
milk samples. The PLS regression model was obtained with the R-square 93% and
with 1.38 RMSECV(Root mean square error of cross validation) value having good
prediction with RMSEP (Root mean square error of prediction) value 1.50 and
correlation of 0.95. This recently developed method is non-destructive, low-cost,
no need of much sample preparation and having sensitivity level less than 1%
level of hydrogen peroxide adulteration. This recently developed method is fast
and simple, being suitable for the control of raw milk in a dairy industry or
for the quality inspection of commercialized milk.