Waters Corp. is targeting food safety and other applications with its new system that bypasses traditional timely sample preparation using a hollow blade similar to a surgeon’s scalpel coupled with software and a mass spectrometer.

Called the Rapid Evaporative Ionization Mass Spectrometry (REIMS) Research System with iKnife Sampling, it can help researchers quickly differentiate samples and identify their features, according to the company, giving them more insight into the chemical and biological systems they are studying.

Its biggest differentiator from traditional liquid chromatography mass spectrometer (LCMS) and molecular techniques like polymerase chain reaction is that is works without requiring sample preparation. The iKnife cuts a heated sample, forming a vapor rich in chemical information. The iKnife is about 1 millimeter thick and 2 centimeters long. The vapor moves through it and an attached 3 meter long tube to a transfer capillary, where molecules are ionized at a heated impactor surface and potential contaminants are removed. The ions are analyzed by time-of-flight mass spectrometry (TOF MS) to get a molecular profile.

“LCMS depends on taking a sample. If you take a sample from a fish, for example, you must homogenize it, centrifuge it and filter it. It’s quite a manually intensive process, and a lab technician has to be sitting with it for some hours,” says Mike Wilson, PhD, who is product manager of benchtop TOF MS at Waters’ office in Manchester, U.K.

Waters acquired the REIMS technology from MediMass Ltd., of Budapest, Hungary, in July 2014. The company was in a three-year collaboration with MediMass and Imperial College London focused on advancing the technology.

Dr. Wilson says the system will be available as both a kit listing for about $40,000 that can be added to installed Waters Xevo and SYNAPT mass spectrometers. The company also will sell systems including the iKnife and a box generator, an ion source mass spectrometer and Progenesis QI software starting at around $490,000. The total system cost depends on the technology in the package.

Dr. Wilson says the product could be used both to glean information about a species of meat or fish and potentially to detect food adulteration. He points to a 2013 scandal in the U.K. when horsemeat was found to be mixed in with beef. The REIMS with iKnife technology could be used to test first pure beef and pure horsemeat, and then to understand the mixed sample quickly.

The company claims the analytical tool may help the food safety industry come closer to a real-time result.

Dr. Wilson expects initial customers to be researchers in universities and institutions focused on food analysis.

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Placing a sample into an automated rapid microbiological tester.

Food producers want to employ rapid methods in order to improve decision making. This implies the rapid method will provide superior information in addition to providing it faster. However, there are a number of indirect issues to consider when deciding to commit to a rapid test method that ultimately influence the method’s overall effectiveness.

The Laboratory Environment

Among the elements to be considered are energy, space, and waste. Many of the existing approaches are culture methods that rely on the incubation of samples in a selective or nutrient medium in order to grow, count, and identify the relevant organism.

Routed in 19th century microbiology, classic culture methods come from an era when almost all processes were manual. For example, due to readability limitations of plate counting methods, multiple replicate plates are necessary. Successive dilutions of the original sample are needed to be able to identify target colonies.

These processes take up significant space in large incubators. Most culture methods are conducted for a fixed time. Therefore, the laboratory incubator ends up being large and energy inefficient. In places were energy costs are still relatively low, this might not appear to be a problem. However, in most of the world, energy cost reduction is a central driver to operating a successful business. When the rapid method is considered, the cost of the energy to produce a result is rarely taken into account.

Similarly, space is at a premium in the food QC laboratory because most of the space is naturally allocated for preparation, processing, production, and packing. As noted, the large incubators needed to operate internal microbiology QC have an impact on the space as well as energy cost.

Bench-top space is a major issue because most labs try to use flexible spaces for multiple tasks. Yet, introducing a piece of analytical equipment usually needs a dedicated space, so it makes sense that “footprint size” is considered for test equipment.

The use of consumables and labware has evolved considerably since the mid-20th century. While there is still a need for reusable glass dishes and containers, much of the developed world has moved to disposable labware. The amount of waste from the average lab operation has increased markedly. Once again, in the case of plating methods, the basic concept of serial dilution and pipetting of samples creates a lot of waste. Any rapid method should hope to mitigate waste generation.

It is interesting to consider alternate testing spaces. Some QC operations would like to test food samples as close to critical control point as possible. However, the constraints of the traditional methods force manufacturers to consider either a microbiology lab or a dedicated space within another functional lab, such as a chemistry or materials lab. QC professionals should seek out rapid methods that can be used outside the traditional lab environment.

A good example of placing a rapid method in a more productive location can be found in meat carcass cleaning and preparation operations. The traditional method is to swab the meat carcass at various stages of processing. This is done in order to ensure no contaminants have infiltrated the cleaning process.

Transporting swabs to the microbiology lab requires the use of transport media and coolers with ice packs to stifle microbial growth. Yet the use of a rapid method that can test on site affords the production and QC staff a number of advantages. One is the very short path to the analytical equipment. Another is the reduction in sampling and transfer steps. With good aseptic technique and adequate training, the measurement goal is achieved without the need for a traditional microbiology lab.

Human Resource Factors

Absolute automation of microbial sampling and analysis is still a theory, at least for the average food producer. People have to conduct sampling, testing, analysis, and recording with the goal of generating consistent, correct, and useful information to maintain quality. Adoption of a rapid method should seek also to reduce manual steps, thereby reducing variability. The technique may be fast, but it cannot be complete unless it removes as many potential error sources as possible.

Looking at plate count methods for microbial enumeration, it can be seen how manual processes provide a breeding ground for errors. Food samples are weighed and then initially diluted in a specified liquid medium. The weighing and measuring is an error source.

The next step for many plate-counting methods is the serial dilution of the sample in order to provide plate readability. This might require four or more successive dilutions where measuring and pipetting errors can creep in. Most accredited techniques require the testing of replicate samples, adding to the amount of sample material and hardware, all of which has to be properly disposed of.

Common Sources of Error

One of the most common sources of error in the microbiology lab is the incorrect pipetting of small volumes of liquid. Once the serial dilutions are prepared, each one might be plated due to a lack of confidence that one of them is the accurate count. Even with the general acceptance of agar plate alternative technologies, the act of preparing and applying the sample to many plates is prone to error.

Of course, the microbes don’t comply with our need to see repeatable and clearly defined data. Colony counting is beset by subjectivity. Microbial colonies can vary in size and shape. They can swarm and spread. Some parts of the plated sample are unwanted artifacts that look like colonies. Plates might be contaminated from surrounding environment. This leads to one of the highest possibilities of error—plate counting itself. Once again, technology tries to rescue the situation with camera-based counters to remove the human element. So, it can be seen from the example of microbial plate counting that reducing steps is advantageous. Also, the right level of automation and correct choice of sampling equipment helps reduce errors.

Ergonomics

An often-unrecognized effect of manual methods in the QC lab is the physiological effect on the technician. Repetitive motion disorders are a real concern for companies who have invested time and effort in the training of skilled technicians. It seems to make sense that by reducing manual steps and the number and frequency of replicates, the physiological burden from staff members will also be relieved.

Choices of rapid methods in the dairy industry offer some insight into how the food companies’ investment in skilled human resources can be supported and rewarded. By choosing a total plate count, or TPC, method that uses only the raw milk as a sample, the need for dilution media is removed. This in itself saves time in preparing media and storing it. Then the probability of error in pipetting and delivering the media is negated as well.

By choosing a technology with high sensitivity and dynamic range, the need for serial dilution is eliminated. By adopting a technology where the sample size is relatively large and the quantitative outcome is not adversely affected by errors in sample size, a more reproducible result is gained. The technician’s job is more easily replicated with fewer repetitive motions.

Opportunity Costs

Buried in the justification for purchasing a new rapid test method is the opportunity cost. Trained technicians should be applied to the most challenging QC tasks that their training will support.

Not all test methods are created equal in terms of complexity of preparation or analysis. An evaluation of what tasks can be automated or outsourced will maximize the technician’s productivity. Test workload continues to expand, driven by regulation and customer desire for safer food and more detailed evaluation of possible spoilage or health drivers.

With test volume increasing, the right degree of automation along with good data generation can assist in guiding critical tasks toward the best-equipped people.

Summary

Data generation speed is only part of the story when selecting an alternate or replacement test method. By considering the workflow and effect on the lab environment, food companies can save costs and increase productivity. By considering the number and complexity of tests and QC steps, the skills and wellbeing of the staff can be protected, producing a healthy and productive workforce.

Traylor is business manager, microbial detection, at MOCON. Reach him at ATraylor@mocon.com.

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