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Farm-Scape, Episode 2213

Modern methods for detecting the presence of the foodborne pathogens that can make us sick along with new compounds, procedures and protocols designed to keep them out of the food have allowed Canada's meat processors to extend the shelf life of fresh meat to almost unimaginable periods of time.

Next week (August 10-11) scientists, government officials and meat industry stakeholders will gather in Calgary when the Canadian Meat Council hosts a session which will examine “Advanced and Rapid Methods in Quality Control of Meat and Meat Products.” The session is intended to update council members and other interested stakeholders on the latest developments in food preservation and safety.

Food Safety Methods Better Today Than Ever

“I should say that the methods we have today have never been better,” states Canadian Meat Council technical services director Parthi Muthukumarasamy. “Over the years it has evolved and now we are talking a matter of ten to 15 minutes [to detect and identify pathogens] compared to days for culture tests so we are really fast and most of the methods are accurate.”

Several Organisms Cause Concern

Dr. Mansel Griffiths, the director of the Canadian Research Institute for Food Safety at the University of Guelph and senior industrial research chair in dairy microbiology notes, “The sorts of organisms that we are interested in detecting in the meat industry are obviously things like salmonella, e. coli, particularly e. coli 157 – that’s the bug that caused all the problems at Walkerton. We’re also interested in other organisms with strange names such as campylobacter and listeria monocytogenes. All of these can be found in different types of meats at various levels.”

Dr. Griffiths will examine “Molecular methods for detection of foodborne pathogens” when he addresses the conference Friday (August 11). He notes, “Currently we use culture based methods. That is, we rely on growth of the organism on media that selects for the specific pathogen that we are looking for. The problem with these methods is that they’re slow because they require the organism to grow.”

Molecular Detection Methods Replacing Cultural Detection Methods

However, Dr. Griffiths explains, “Molecular methods basically detect the genetic sequence that’s unique to a particular organism. The advantage of doing that is that we can detect the presence of genes that make the organism pathogenic, the genes that are responsible for producing the substances that make us sick. It’s a much more specific method for detecting the organisms that are actually going to cause illness. They also have the advantage in that they are faster than the culture based methods and they are easier to use.”

“Gradually they’re replacing the conventional systems,” he says. “They are more specific for the organisms that are likely to make us sick so we can target certain types of organisms much easier than using culture techniques. They can be more sensitive than culture techniques. That is they can detect fewer numbers of cells and they can be done much more rapidly.”

Polymerase Chain Reaction Becomes More Common

Dr. Griffiths notes, “The one that's being used with increasing frequency is a technique called real time PCR, real time polymerase chain reaction.”

He says, “We are all familiar with programs like CSI and other similar programs. PCR is the technique that they use to amplify the DNA that they find at crime scenes for instance. It’s a way of making many copies of a target piece of DNA that we know is unique to the organism that we’re looking for. The real time part of it means we can detect whether the gene sequence, the DNA that we’re interested in, is being amplified in real time. As it’s being amplified we can detect the products of the amplification reaction.”

Procedures Used in Clinical Microbiology Being Applied to Food Safety

“There are other methods that are available,” he admits, “but the ones that are being used increasingly in the food industry are the real time PCR methods and there are a couple of companies that produce methods commercially that are used in the food industry.”

He notes, “They are used on a variety of products. They are used on meat products; they are used in the dairy industry; they are used in the fisheries industry; to a certain extent in the produce industry, so they are starting to be used in the whole range of the food processing industry.”

Dr. Griffiths points out, “As with a lot of techniques, we’re taking things that have been used in clinical microbiology for a long time and starting to apply those to the food industry. These techniques have been around for a little while but only now are we starting to use them in the food industry.”

Methods for Keeping Pathogens Out Also Contribute

As techniques for detecting and identifying foodborne pathogens have advanced so have the methods and tools designed to keep them out of the food.

Dr. Rick Holley, a professor in the Department of Food Science at the University of Manitoba estimates, “Over a period of the last 15 years, I would say, we’ve seen shelf life extensions from 30 days with pork to 55 days, largely as a result of improvements in plant sanitation, temperature control as well as improvements in packaging materials and also packaging approaches using some of those materials.”

Dr. Holley is scheduled to outline how scientists are “Investigating causes of spoilage in meat and meat products and their effective control.” He explains, “The technology for packaging and shipment of fresh meat over fairly lengthy periods of time is reasonably well established in the scientific literature and has good technical support, generally speaking, from the industry that supply materials to the fresh meat industry.”

Modern Tools Include New Compounds, Temperature Control Equipment, Packaging Materials

He adds, “You have chemical suppliers who make procedures, protocols, available to the industry which they can then follow and apply. The technology in that area is never static. It’s changing all the time as new sanitation compounds become available. With those of course are improved procedures for application of those new sanitation compounds.”

Dr. Holley stresses, “The best possible opportunity for attaining shelf life is keeping the temperature as low as possible without freezing the meat. What that means is using temperatures that are in the vicinity of about minus 1.5 Celsius, plus or minus a half a degree. That type of temperature control is expensive and requires equipment that’s very precise so you don’t freeze the meat. As soon as you freeze the meat you lose quality.”

He continues, “Packing materials [are] very important in terms of achieving the shelf life that industry targets. I’m thinking now of film materials which, while they have low oxygen transmission, are shrinkable so you get less opportunity for spaces in the package, between the package and the surface of meat, and get therefore less extraction of the liquid material during storage, shipment and distribution to customers.”

“Those three things,” he concludes, “optimize the shelf life that’s attainable during packaging, distribution and sale of fresh meat products, both pork and beef and other species as well, lamb and goat meat.”

Muthukumarasamy suggests new public perceptions of these issues and the new regulations that are coming up every day have provided much of the incentive to improve. However, he notes, “The industry people too take this issue very seriously.”

Systems Not Yet Foolproof

Despite the success, problems do occasionally occur. Dr. Holley points out, “Over the last seven or eight years here at the department of food science we have been addressing problems that occur periodically in the meat industry…largely in order to help the pork industry in western Canada.”

He explains, “Occasionally, there are instances where something gets omitted or a different bacterial organism may, in some fashion, be concentrated in a micro-niche in a plant operation and actually be selected for unknowing to the folks that are operating the plant and cause problems. What we’ve attempted to do, at the request of industry a number of times, is address these problems and attempt to try and identify these organisms and the conditions responsible for specific problems.”

He notes, “The discovery that what we had originally thought, in many cases, were harmless or inert organisms in these environments indeed have a role to play in shortening shelf life has served to help the industry a great deal. We have had organisms that we long thought were not involved in the spoilage process and low and behold, when we take a really close look, what we find is son of a gun these guys have been hiding from us as and do have impacts that we can measure in terms of shortening shelf life.”

Attention to Food Safety Remains Strong

Muthukumarasamy suggests, “Just to show how interested [in food safety] our members are, nearly 90 people will be attending this symposium and all the major meat industry are sending at least one or two people to attend the symposium.”

He says, although these kinds of symposiums have been organized in the U.S. for years, this is the first time such an event has been organized in Canada.

He notes, “The recent tools we have are advanced and accurate too so they save a lot of time and they are very easy to use in any laboratory.”

He concludes, “Today we are much better than even last year. There’s a vast improvement every day.”

Staff Farmscape.Ca