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New Listeria Species Discovered

New Listeria Species Discovered: What Does This Mean For Food Safety?

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Reading Time: 2 minutes

A new species of Listeria has been discovered by Scientists from Cornell University. Five previously unknown species of Listeria have been added to the list. The most infamous of the genus you may recognise; Listeria monocytogenes, an opportunistic pathogen that causes listeriosis. A food-borne illness affecting several processed foods.

Where was the new Listeria species discovered?

While examining the prevalence of listeria in agricultural soil throughout the U.S., Cornell food scientists have stumbled upon five previously unknown and novel relatives of the bacteria, according to new research published May 17 in the International Journal of Systematic and Evolutionary Microbiology.

The discovery, researchers said, will help food facilities identify potential growth niches that until now, may have been overlooked – thus improving food safety.

Listeria are notoriously difficult to remove from the food factory. They are persistent, able to resist chemical treatment and grow is difficult to reach areas, whilst being able to grow well as refrigeration temperatures.

“This research increases the set of listeria species monitored in food production environments,” said lead author Catharine R. Carlin, a doctoral student in food science. “Expanding the knowledge base to understand the diversity of listeria will save the commercial food world confusion and errors, as well as prevent contamination, explain false positives and thwart foodborne outbreaks.”

What makes the new species unique?

One of the novel species, L. immobilis, lacked motility, or the ability to move.  Listeria move a lot. Among scientists, motility was thought to be common among listeria closely related to L. monocytogenes, a well-known food-borne pathogen – and used as a key test in listeria detection methods. This discovery effectively calls for a rewrite of the standard identification protocols issued by food safety regulators, Carlin said.

“This paper describes some unique characteristics of listeria species that are closely related to Listeria monocytogenes, which will be important from an evolutionary perspective and from a practical standpoint for the food industry,” said co-author Martin Wiedmann, Ph.D. ’97, the Gellert Family Professor in Food Safety and Food Science. “Likely, some tests will need to be re-evaluated.”

After naming L. immobilis to reflect this organism’s non-motile characteristic, three of the other species were named to honor other listeria researchers:

  • L. cossartiae for Pascale Cossart, a bacteriologist at the Pasteur Institute of Paris;
  • L. farberi for Jeff Farber, a microbiologist at the at the University of Guelph, Canada; and
  • L. portnoyii for Daniel Portnoy, a microbiologist at the University of California, Berkeley.

The species L. rustica was taken from the Latin word “rusticus” and signifies its rural origin. 

The research further supports the need to separate testing of Listeria species from the specific detection of Listeria monocytogenes.

The new study was published in the International Journal of Systematic and Evolutionary Microbiology.

Source: Cornell University

easter eggs food safety

Food Safety During Easter

Reading Time: 2 minutes

As we head into the Easter holidays many countries throughout the world are either well into the vaccination program or heading into the 3rd wave of COVID-19 infections. Food safety during Easter should not be forgotten during this critical period. 

Whether you’re celebrating your Seder meal with brisket or Easter dinner with ham or lamb, keep food safety in mind. Eggs also are popular for traditional Passover and Easter celebrations and require proper food safe handling. 

It is important to take precautions with eggs and other perishable foods to avoid food-borne illness.

Here are our tips for this Easter:

  • Consider using colorful plastic Easter eggs with treats or toys inside for your Easter egg hunt.
  • Be sure and inspect the eggs before purchasing them, making sure they are not dirty or cracked.
    • Dangerous bacteria may enter a cracked egg.
  • When cooking, always start with clean hands.
    • Wash your hands with warm water and soap for 20 seconds before and after you handle food. 
  • Remember to avoid cross-contamination by keeping kitchen surfaces and equipment clean and using separate knives and cutting boards for different foods. 
  • Use only food-safe dyes on Easter eggs.
  • After decorating the eggs, put them in the refrigerator right away. 
  • Store eggs in their original cartons in the refrigerator rather than the refrigerator door.
  • Abide by the “best by” date on the egg carton.
    • It is best to throw out old eggs than to risk sickness.
  • When you’re decorating, cooking, or hiding Easter eggs, extra care is needed as eggs are handled a great deal more than usual around Easter. 
  • If you’re having an Easter egg hunt, consider hiding places carefully.
    • Avoid areas where the eggs might come into contact with pets, wild animals, birds, reptiles, insects, or lawn chemicals.
  • Make sure you find all the eggs you’ve hidden and then refrigerate them.
    • Discard cracked eggs.
  • Eggs should not sit out at room temperature for more than two hours.
    • Keep hard-cooked eggs in the refrigerator until ready to serve.
  • All cooked egg dishes should reach a safe minimum internal temperature of 70° C (158 °F) as measured by a food thermometer.

Food Safety for cooked meals

  • Be sure to allow plenty of time to thaw a frozen brisket.
  • Bake the brisket, fat side up in a baking dish, in an oven set no lower than 180°C (356° F).
    • The brisket is safe to eat when it reaches an internal temperature of 65°C (149°F) and is allowed to rest at that temperature for three minutes. 
  • Ham is a popular meat for the Easter table. Ham is either ready-to-eat or requires cooking before eating.
    • Fresh, uncooked hams must be cooked to reach a safe minimum internal temperature of 70°C (158°F).
    • Ready-to-eat hams are cooked at the plant and can be safely eaten right out of the package and can be served cold or heated to serve warm.
  • Lamb is another popular dish.
    • For food safety, a leg of lamb and other cuts should be cooked to a safe minimum internal temperature of 65°C (149°F).
Shelf-life checks retail store

Shelf-life: How Long Should Foods Last?

Reading Time: 4 minutes

What is the shelf-life of a product?

The Shelf-life of a product can be defined as a group of microbiological, chemical and sensory tests performed on food products that determine at what point in time is the product no longer safe to consume and when the product losses its peak quality markers. Further to the above, the Shelf life is a guide for the consumer of the period of time that food can be kept before it starts to deteriorate, provided any stated storage conditions have been followed. The storage conditions are particularly important in the shelf-life of the product and can either be refrigerated, frozen or ambient depending on the product.

The length of the shelf-life of a product is dependent on the following factors:

  • The types of ingredients
  • Manufacturing process
  • Type of packaging
  • Storage conditions

The shelf-life is indicated by labelling the product with a date mark, which can either be a “best before” or “use by” date, depending on the product.

How is the shelf-life of a product determined?

The shelf life of a food product begins when the product’s processing and packaging is complete and is ready to be distributed. By performing shelf-life testing, you are able to accurately define dates for your products, ensuring that the quality remains acceptable and safe for consumers.

There 3 key areas of testing involved with shelf-life tests.

Microbiological shelf-life tests

The most critically important is the determination of the microbiological safety of the product. In other words, are there any ‘germs’ in the product that can cause food poisoning. In addition, testing for food spoilage ‘germs’ is integral to the shelf-life tests which tell us at what point does the product exceed the limit of allowable ‘germs’ to the point that it is no longer safe to consume.

Chemistry Quality Tests

 The second key area in shelf-life testing involves food quality chemistry. These tests help determine the ‘freshness” of the product including moisture content (at what point does the product dries out), acidity levels, pH and so on.

Sensory and physical tests

During the shelf-life of a product, the food should remain safe to eat, maintain its appearance, odour, texture and flavour. This covers the third key area of the tests, sensory and physical evaluation. A panel of experienced laboratory technicians can perform ‘taste tests’ to determine whether the product maintains expectations throughout the expected shelf-life.

Why Is Shelf-Life Testing Necessary?

A shelf-life test can only be valid for the specific set of ingredients, packaging, and processing of that particular product. It is therefore wise to have finalised and completed the recipe and processes before undertaking a shelf-life study.  If changes are made to any step in the process, a set of tests needs to be undertaken.

The need for shelf-life tests came as a result of the availability of ready-to-eat food that have extended shelf-life in our retail environment. The improved science of quality around extending the life of the product, meant that measures needed to be in place to minimise the potential for microorganisms to be present in foods in hazardous numbers.

These safety measures became critical to the food industry and to consumers. The tests used also help identify potential problems in production and reduce the risk of product recalls, ultimately increasing profitability.

Complying to legal requirements

Legal requirements regarding date markers

The food laws throughout the world, have a common ground in determining if and which dates should appear on product labels. The below specifically relates to the use by or best before dates:  

  • “Use by” date: to be mandatory on perishable pre-packaged foodstuffs and a prohibition regarding the sale thereof after the date has expired as it relates to the safety and/or suitability of the products in question, i.e. microbial growth
  • “Best before” date: to be mandatory for non-perishables but no prohibition regarding placed on the sale thereof after the date has expired in view of it relating only to the optimum freshness, thus quality aspects, of these products.

It is therefore absolutely critical that the microbiological safety of the product be determined.

Who is responsible for calculating a shelf life?

Any individual or company who sells or packages food intended to be consumed is required by law to measure the shelf-life of their product. The food label is required to display the result of the tests, ie. “use by” or “best before” dates, as well as the storage instructions.

Refrigerated Shelf-Life Testing

The typical shelf-life of refrigerated products range from 3 to 14 days depending on the product. Samples are stored in the fridge at a maximum of 5°C and tested for stability using the 3 key areas of testing, which include regular testing for spoilage organisms as well as pathogen screening. Trials can continue beyond the targeted shelf-life unless the product fails earlier.

Frozen Food Shelf-Life Testing

The typical shelf-life of frozen products range from 3 to 6 months, and in some cases up to 1 year depending on the product. Such shelf-life tests are lengthy because of the viable duration of the product. Frozen foods do eventually deteriorate during storage and are mostly quality related. However, research has shown that some bacteria are able to survive when extensive temperature abuse takes place. Such as Listeria monocytogenes.

Ambient Shelf-Life tests

Shelf-stable food (ambient food) are products that can be safely stored at room temperature in a sealed container. This includes foods that would normally be stored refrigerated but which have been processed so that they can be safely stored at room or ambient temperature for longer shelf life. The typical shelf-life of refrigerated products range from 6 months to 2 years depending on the product. Fortunately, these tests can be “accelerated” by keeping the product in an incubator (37° C or 98.6°F). One week in the incubator equals one month of shelf-life.

Understanding the end of shelf life 

What constitutes the end of shelf life?

Microbiological testing indicates that when the presence of spoilage organisms grow to a level beyond acceptable limits, the product has expired. This endpoint is further defined by relevant food legislation and guidelines provided by government or professional organisations or accepted industry practices.

This endpoint is further supported by quality and food chemistry tests. These acceptability limits are often chosen based on the food industry and sensory perception as an indicator of product failure. Product acceptability can be determined when there is a significant change in the quality in the ageing sample compared to a fresh sample by using comparative testing. Sensory and physical testing (such as odour, taste, appearance and texture) can help demonstrate this endpoint.

What are the food safety pillars?

No-Risk Of COVID-19 From Frozen Foods

No-Risk Of COVID-19 From Frozen Foods

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Reading Time: 3 minutes

In September 2020, China suspended importing fishery products from Indonesia due to novel coronavirus contamination on outer packages. There were also reports of around 10 cases of SARS-CoV-2, the COVID-19 virus in the frozen products or its packaging from Russia.  Further reports have highlighted safety issues on imported frozen foods.

There are two issues to be aware of in these reports.

Firstly, the tests conducted do not detect whether these were an active or dead virus. This is because the PCR test only detects the RNA of the virus. It cannot tell us if the virus was alive or not. The time it would have taken to transport the frozen goods may suggest that the virus was no longer alive, despite frozen temperatures being ideal for the preservation of the viral material.

Secondly, the frozen product itself did not test positive for the virus, but rather the outer packaging, of which we know is possible. The virus is able to survive without a host for a few hours to several days. This contamination points to poor hygiene practices of those who may have handled the packaging from packing, transport and distribution.

There is a large amount of evidence showing that meat and fish packing houses are at greater risk of human to human transmission of the virus because of the close proximity working conditions for staff in the warehouses. Social distancing in close to impossible to maintain, due to the nature of the work environment.

What do we know about food safety & the virus?

Food Safety can be defined as handling, preparing and storing food or drink in a way that best reduces the risk of consumers becoming sick from the food-borne disease. We know that SARS CoV-2 is a respiratory virus, which means you have breath in the virus either orally or via the nasal passage. Food safety risks involve foods being eaten and need to access your gut in order to cause harm.

What are the food safety risks?

Contamination of food and beverages can happen in a few ways:

  • The food handler is ill or has handled raw foods without washing his/her hands. The person has not maintained good personal hygiene, ie. washed their hands after going to the toilet.
  • Raw foods were not corrected heated in order to kill any bacteria or viruses present in the product.
  • Poor temperature control allowing the growth of bacteria to dangerous levels that were present in low/safe numbers before.
  • Cross-contamination due to poor storage or further handling.
  • Incorrect cleaning or use of chemicals.

What do we know about controlling the virus?

  • SARS CoV-2 is a respiratory virus
  • Infection occurs by breathing in the virus from an infected individual or by contact of a contaminated surface, after which you touch your face, mouth or eyes causing infection.
  • The virus is susceptible to detergent cleaners and various sanitisers.

Risk Of COVID-19 From Frozen Foods?

To be fair, we can’t with full confidence say: “there is no-risk of COVID-19 from frozen foods”. But, rather it is very unlikely that any infections have occurred as a result of consuming foods. As of the date of publishing, there have been zero reported cases. However, the reported cases mentioned in this article may have been as a result of handling contaminated packaging and not keeping good hygiene.

It is more likely that the reported cases were as a result of close contact with an infected person, rather than as a result of handling of the packaging. There is no conclusive evidence that can without a doubt show infection from the packaging directly.

How to minimise the risk of COVID-19 infections

As a reminder, there are 3 keys ways to prevent getting infected with the novel Coronavirus.

  • Keep 1,5 – 2 meters (6ft) apart from another person.
  • Wear a mask to minimise the risk of spreading the virus or from getting infected.
  • Wash and sanitise your hands after handling any common use items or that you may suspect is contaminated with the virus.

What are the food safety pillars?

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