Food Contaminants: the noGood, the Bad & the Ugly Part 1: 3-MCPD/glycidol

We're genetically programmed to love fatty food, whether it's a fried breakfast, fish & chips or just a bag of potato crisps. And, while salt, lemon juice, tartare sauce and pepper all add to taste, there are some seasonings that we could all do without.

Top of the list are Chloropropanols and Glycidol; genotoxic, carcinogenic food process contaminants formed during edible oil processing, reprocessing and baking. They are of particular concern being implicated in having long term adverse effects on the kidney (especially in infants where formula fed infants may slightly exceed the safe maximum permitted levels defined in the European Commission regulation 1881/2006) and male reproductive health.

To comply with the regulations oil refiners, re-processors (e.g., fried potato products manufacturers) and infant formula manufacturers must monitor and measure 3-MCPD and glycidol levels in their products however, this is not an easy task due to the complexity of the sample preparation:

• Capacity, throughput and turnaround times are limited by sample prep bottleneck
• Typically in-sourced to investigatory analysis team or outsourced to specialist CRO
• High labour and instrumentation (GC-QQQ) costs with manual sample prep
• Complexity increases likelihood of human errors, poor accuracy and reproducibility

Monitoring and measuring 3-MCPD and glycidol accurately and precisely is a significant cost to oil refiners and infant formula manufacturers. For refiners, laboratory turnaround times mean that the results are retrospective and cannot identify problems before the process is out of control. For infant formula manufacturers, raw materials cannot be used until they have been tested.

The GERSTEL 3-MCPD/glycidol solution help producers get better quality results more quickly and at a lower cost by fully automating the reference methods ISO 18363-1, AOCS Cd 29c-13, and DGF C-VI 18 (10). The solution:

• Reduces turn around times
• Provides near realtime or realtime feedback (near-line/at-line/on-line installation)
• Reduces consumables/solvent/reagent use (helps your ISO 14001 certification)
• Reduces operational costs - owned by QC rather than investigatory analysis team
• Reduces CapEx costs - for oils GC-MSD rather then GC-QQQ
• Reduces labour costs and frees-up people to add value elsewhere
• Improves data quality (accuracy, precision, gross errors)
• Delivers ease of use through Maestro, low maintenance options (JetClean, GERSTEL Automated Liner Exchange) and early maintenance feedback
• Eliminates manual data processing with fully automated data analysis and reporting
• Delivers realtime reporting/feedback when integrated with LIMS/SCADA

3-MCPD & Glycidol Solution Overview

Chloro-propanediols and glycidyl fatty acid esters are formed during edible oil refining (bleaching and deodorisation) processes, 2-MCPD, 3-MCPD and glycidyl fatty acid esters can be generated, resulting in a contaminated product.

The GERSTEL 3-MCPD Sample Prep Solution enables automated determination of these potentially health relevant contaminants supporting the methods ISO 18363-1, AOCS Cd 29c-13, and DGF C-VI 18 (10). 

In fats and oils, glycerol is contained in the form of fatty acid esters (triglycerides). Since many oils are not suitable for consumption and are not stable in storage in their native, untreated form, they are refined to remove unwanted substances. The refining process involves a deodorization step, in which the oil is heated with hot steam to between 200 and 230 °C under vacuum to remove unwanted odor and flavor active substances along with other unwanted substances. When chloride is present, however, the heat treatment can result in the substitution of a fatty acid chain by a chloride atom forming 2-MCPD- and 3-MCPD fatty acid esters, respectively. Under these conditions, glycidyl fatty acid esters can also be formed. These contaminants are classified as potential health risks. 

To prepare edible oils for consumption, a refining process is frequently required. During this process, 3-MCPD-, 2-MCPD-, and glycidyl fatty acid esters can be formed. A reduction in their levels is typically achieved by optimizing the refining process conditions.

For the determination of 3-MCPD, the fatty acid esters, as well as glycidyl fatty acid esters, the German Society for Fat Sciences (DGF) recommends the unified DGF C-VI 18 (10) method, based on a complex sequence of sample preparation steps combined with GC/MS determination. The DFG C-VI 18(10) method is similar to the ISO 18363-1 and AOCS Cd 29c-13 methods, which are practically identical. The 3-MCPD Sample Prep Solution developed by GERSTEL automates the reliable indirect DGF method one to one using reduced volumes. If required, 2-MCPD can be determined as well. 

The GERSTEL MultiPurpose Sampler (MPS robotic) Dual Head version, automates all steps including liquid handling, liquid-liquid extraction, evaporative concentration of extracts, change to a GC compatible solvent and derivatization of the analytes. If the MPS is integrated with a GC/MS system, the entire process including GC/MS analysis is automated and automatically optimized for highest productivity and throughput. 

The evaporation step ensures that the required limits of determination can be reached using a single quadropole mass spectrometer (MSD) for most matrices. In addition, excess derivatization reagent is removed for improved GC/MS system stability. The PrepAhead function ensures maximum productivity and parallel processing of individual tasks. When performing differential determination of 3-MCPD and glycidol, 24 samples can be processed in 24 hours, based on 48 GC/MS analysis runs. The GERSTEL 3-MCPD Sample Prep Solution supports the following standard methods: ISO 18363-1, AOCS Cd 29c-13, and DGF C-VI 18 (10).

Depending on the instrument configuration, introduction of the prepared extract to the GC/MS system can be included. When performing differential determination of 3-MCPD and glycidol, 24 samples can be processed in 24 hours, based on 48 GC/MS analysis runs.

GERSTEL mVAP performs evaporative concentration of up to 6 samples in parallel. Vacuum level, temperature and agitation speed are user defined and can be optimized for the analytes in question. mVAP makes it possible to reach lower limits of determination. When analyzing for 3-MCPD and associated compounds in edible oils and fats, evaporation of excess derivatization reagent also helps to keep the GC/MS system stable, resulting in improved long term stability and accuracy. Depending on the type of oil analyzed, a concentration step enables single quadrupole mass spectrometers to reach the required limits of detection.

GERSTEL quickMIX enables extremely fast and efficient mixing and extraction of samples as part of an automated sample preparation process. The mixing power is comparable to that of a vortex mixer making quickMIX highly suitable for extraction of oil samples. In quickMIX, samples are placed in special trays that hold up to 6 samples, depending on the vial size, for simultaneous, batchwise agitation.

Further Reading:

GERSTEL 3-MCPD & Glycidol Solution Brochure

GERSTEL AppNote-191