Chem 126

Mark Christopher Cheetham                                        Chem 126 TF 7AM-10AM
Jastin Dave Estandarte                                                Group 5
Trisha Kaye Jongo

Problem:

You are a chemist in-charge in evaluating the raw materials used in a Halal certified hotdog factory in Singapore. One of the major ingredients you purchased is minced beef. Your boss is suspecting that your supplier is mixing it with cheaper meat (pork and horsemeat). Proposed an analytical method that will determined if indeed the minced beef is adulterated with pork.

Methods:

1. Detection of horse and donkey meat using PCR detection

In this method real-time PCR assays were developed specifically for horse and donkey DNA, which are applicable to the detection of even low levels of horse or donkey meat in commercial products through the aid of optimized horse and donkey primer probes. Prior to the PCR experimental stage, DNA was extracted from samples using a special DNA extraction kit, as the collected samples were subjected to elution and extraction with certain buffers. For samples in complex meat matrices, DNA was also extracted through another special method using a DNA purification system. Afterwards, the prepared samples were subjected to a real-time polymerase chain reaction, which includes the addition of a TaqMan Buffer, and the presence of the specific probes that were prepared beforehand. After the reactions, the yielded results present signals which respond to the optimized probes. The use of DNA, rather than protein, was proven to be a better method of analysis as proteins are denatured during heat and pressure processing, making the detection of species in a sample more difficult.

1.  Detection of pork fat in processed foods using HPLC

Another way of detecting of pork fat in processed foods is through HPLC which separates the triacylglycerols (TG) of animal fats using refractive index detection. TG is isolated from the pork fat by column chromatography. HPLC is a good separation technique and has application to the analysis of animal and vegetable fats and oils. HPLC-profiling of derivatized TG have been reported for the detection of pork in beef but major disadvantage of the method is lengthy and needs tedious sample preparation.

FTIR spectroscopy combined with a chemometric technique is an emerging reliable analytical method to identify meat types present in processed foods. In the field of halal analysis, the combination of FTIR spectroscopy and chemometrics has been used for analysis of lard in the binary mixture with other animal fats such as analysis of pork fat in meatball products and meatball broth. The FTIR spectra of evaluated samples were acquired in the mid infrared region (650-4000 cm–1) using an ABB MB3000 FTIR spectrophotometer. The instrument was equipped with a deuterated triglycine sulfate (DTGS) detector and KBR as the beam splitter. The spectra were scanned at a resolution of 4 cm‾1 with 32 scanning. The FTIR spectra were processed using FTIR software of Horizon MB version 3.013.1 (ABB, Canada). Quantitative analysis of fat extracted from processed food containing pork meat was performed using Partial Least Square (PLS) calibration. The major advantage of this method is that FTIR is rapid, non-destructive and does not involve laborious sample preparation.