Listeria in Australia

We are hearing a lot about listeria lately. Six people have died in Australia, South Africa is experiencing the worst outbreak ever and New Zealand MPI warns consumers about a product MPI consider high risk. All is not as it seems... so keep reading...

According to science most of the cells in our body are bacterial. They are the cells of the bacteria living inside and on us. They are nestled in our guts, our urogenital tracts, on our skin, our mouth and noses. They are entire civilisations of fungi, protozoa and mostly bacteria that live, eat, reproduce and die. According to a teaching poster by the American Society of Microbiology the average human body is made up of 100 trillion cells. 90 Trillion are microbes. Only 10 trillion are human cells. 

It is very important that these cells consist mostly of beneficial, diverse species microbes. Beneficial bacteria is known to be protective of their host. They will defend the gut lining and skin against invaders, but when the bad microbes take over our immunity can suffer. Remember science say

that about 80% of human immunity lies in the gut.

This ABC article cautions that unborn and newborn children and people with weakened immune systems are at risk of Listeriosis. It means that people with under developed or immune problems are vulnerable. Their natural defences may be easily overwhelmed if bad bacteria and their toxins multiply to dangerous levels. Despite all the science available people still wonder why some individuals are so susceptible to getting sick, when others can ingest harmful bacteria without problem. Perhaps this depends on the amount of good bugs we have in our gut to fight off the bad ones. Turn up the volume to listen to a snippet of Dr. Michael Mosley in the episode Gut Feeling by SBS Insight below. See the full story here: Gut Feeling.

According to Peter Pollard an Australian microbial ecologist in this TEDx video 99% of all microbes on this planet are "essential for our very existence. We would not be here if it wasn't for these microbes." He says only a few of the disease causing bacteria and viruses gives microbes a bad name.  Australians recoil when they hear about dangers like sickness or death but things need to be seen in perspective.  

This ABC article says that Listeriosis tends to start with flu-like symptoms, such as fever, chills, muscle aches, nausea, and sometimes diarrhoea. Lydia Buchtmann from the Food Safety Information Council says "for most of us, it's not really an issue. You might have mild fever, feel a bit fluey, or have an upset stomach."

It also warns that on very rare occasions, Listeriosis can become more serious and develop into meningitis or septicaemia.

Another ABC article warns that sepsis, another diagnosis that can be mistaken for gastro, takes 5,000 Australian lives each year. 

According to Bronwen and Francis Percival's book Reinventing the Wheel the recognition of Listeria monocytogenes as a food-borne pathogen was made extraordinarily recently: "it was so rare for any otherwise healthy person to contract listeriosis that nobody imagined that the illness might be caused by an organism present in food. The original study that made the connection was only published in 1983." In addition, few people seem to be aware that Listeria is a family of bacteria that is common to our environment and usually harmless. Listeria monocytogenes is one strain of the Listeria family that can cause harm. The illness is called Listeriosis. This article says: 

"Listeria monocytogenes is harmless to most people, even when ingested at high levels. Many of us will have the bacteria in our guts at some time and they usually pass through without harming us. People at high risk are those with reduced immune function..."

British Microbiologist Jayne Hickenbotham also explains in this video why some people ingest lots of Listeria monocytogenes without problems but certain high risk groups are very vulnerable. 

 

Listeriosis from rockmelon in Australia

According to this article New South Wales Health has confirmed that a sixth person has died from listeriosis linked to contaminated rockmelon. A Victorian woman had a miscarriage linked to the outbreak. A child died. The nationwide total of people affected remains at 19. Three deaths were from NSW and three from Victoria. They are all linked to an outbreak from a farm near Griffith in NSW. Some news reports recommended that people not eat cut rockmelon. The example from Colorado below however shows that even whole cantaloupes are problematic. It's about the bad microbes that sit on the skin of the fruit and some people's inability to defend themselves against the potentially dangerous microbes. The latest confirmed case was a 90 year old NSW woman with significant underlying health issues. According to this article the contaminated rockmelon was exported to at least nine countries.

 

Listeriosis in South Africa 

According to this article the recent outbreak occurring in South Africa is believed to be the largest-ever outbreak to have occurred to date, according to the United Nations. 180 People have died. The Minister of Health of South Africa, Dr. Aaron Motsoaledi, provided an update on the situation, reporting that as of March 2, 2018, the number of laboratory-confirmed cases of listeriosis has risen to 948 since January 2017. There seems to be great confusion as to the exact source of the outbreak. The same article reports that Listeria was linked to polony brands, which is a kind of deli meat.

Previous to this outbreak in South Africa, the second largest outbreak of listeriosis sprung up in 2011, and was linked with whole cantaloupes from Jensen Farms, Colorado—this outbreak had 147 confirmed cases across 28 states. 33 People died.

 

Listeria and ready-to-eat red meat

A new study has found 15 per cent of pre-packed ready-to-eat red meat in New Zealand is contaminated with Listeria Monocytogenes. Packed red meats like shaved ham and beef cold cuts on sale are often the culprits. In a New Zealand article researchers said that better hygiene practises and more effective '"risk mitigation strategies" may be needed to deal with the growing problem of listeria in ready-to-eat meat.

According to the scientist in this article: "the centralised production of prepared ready-to-eat food products... increases the risk of higher levels of contamination, since it requires that foods be stored for long periods at refrigerated temperatures that favour the growth of Listeria. During the preparation, transportation and storage of prepared foods, the organism can multiply to reach a threshold needed to cause infection." Many of our foods are no longer produced and eaten in local food systems. They often travel many food miles in refrigerated storage to foreign countries, thus becoming a hazard to human health. The solution is obvious: local food systems can be safer.  

 

Listeria and pasteurised milk

Lydia Buchtmann from Food Safety Information Council said that listeria is one of the few pathogens that can grow under refrigeration. "It slows its growth, but it can still grow." The following information shows that listeria can grow differently in milk pasteurised at different temperatures and it can have a public health impact.

In this video from the 2016 Raw Milk Symposium at the University of Guelph, Mark McAfee talks about how data shows that pasteurisation of dairy is not a guarantee of food safety. He talks about a study that was done by food researcher Dr. Nicole Martin at Cornell University. It found that if the pasteurisation temperature was 72 °C, it was less likely for Listeria monocytogenes to grow if the milk was contaminated post-pasteurisation during refrigerated storage, than if the listeria contaminated the same milk pasteurised at 82°C. An increase in high temperature, short time pasteurisation temperature did affect the growth of Listeria monocytogenes. Specifically, the time lag before exponential growth was decreased and the maximum population density was increased.

In a recent video at the 42 minute time marker American constitutional law, food and drug attorney Jonathan Emord said of milk produced in the USA: “Pasteurised milk has a notorious reputation for listeria, salmonella every season of the year and particularly in the summer months. We see a spike in the instances of hospitalisations associated with those bacteria because of the pasteurised milk that has not been properly handled.” Pasteurised milk infected with pathogens post-pasteurisation is defenceless. It does not have the same protective systems that regulated raw drinking milk would have.

This Food Safety News article admits: "while pasteurisation of raw milk kills microbes which can cause disease in humans, not all bacteria and their associated enzymes are eliminated in the process. The remaining bacteria can still cause spoilage and quality defects in dairy foods."

There are other Australian examples showing that pasteurised cheese was linked to the death of two adults and one child. No matter how hard some industries defend the safety and profitability of their industries, no food can be considered 100% safe. A recent Farm-to-Consumer Legal Defence Fund article calls the highlighting of the dangers of raw milk, while minimising the dangers present in pasteurised dairy selective science saying: "the alleged safety threats are routinely cited by opponents of raw milk."  

 

Listeria and raw milk

Health officials like to say that raw milk is the perfect breeding ground for harmful bacteria, but that depends on what kind of raw milk is under discussion. There are two kinds of raw milk

Australian microbiologist Dr Ron Hull has given expert evidence about the safety of raw milk and describes it as having "two system of immunity to pathogens", read more about it here. When raw milk comes from healthy, grass-fed animals (grass and hay) the pathogens cannot easily overwhelm the protective systems in the milk.

Many overseas raw dairy farmers have tremendous success with giving their cows a 100% pasture-based diet (grass and hay). They report the animals are robust and healthier with less need for intervention strategies. When holistic pasture management is implemented on the farm the microbiology and nutrition in the pasture is restored. Regenerative farming and a rotational grazing program builds plant diversity and soil microbes. Soil microbes, like mycorrhizal fungi, enable plants to take up lots of carbon and minerals, which makes more nutrients available to the animals, more here. It has a positive impact on the health of both dairy and beef cattle. Animals producing for the raw milk market have to be in excellent health and this is a great way to achieve that in organic farming systems. A veterinarian turned 100% grass-fed raw milk producer in this example is one of many who can show that it is possible to achieve undetectable results in milk quality tests. It is not difficult to make clean raw milk that has a long shelf life of three weeks. It is not hard when you know how to do it...   

A raw milk producer from New Zealand recently had a positive campylobacter test and before that another had their milk recalled because it might contain listeria. These incidents have led to criticism from Professor Nigel French, who is director of the New Zealand Food Safety Science and Research Centre. A few days later the New Zealand Ministry for Primary Industries (MPI) issued a press release reminding to take care when consuming raw drinking milk (RDM) because MPI consider it to be a high risk food.

There is reason to be concerned about New Zealand's raw milk system implemented in 2016. A study of the Animal Products Notice: Raw milk for Sale to Consumers document page 34 reveals that NZ raw milk regulation has little clarification on what cows are not allowed to eat. The regulations force all sorts of other compliance on the farmers but neglects some of the most important aspects that contribute to the food safety of RDM. The feed commonly given to cows in the industrial dairy industry has many recognised risks and mitigation strategies. There is an expectation that the milk produced for this market will be pasteurised rendering the milk free from dangers. We know that some raw dairies in New Zealand only feed pasture to their animals, but what would happen if a farmer from an industrial background feed some common industrial feeds to the herd producing RDM? The New Zealand RDM system has vulnerabilities that some farmers may not be aware of. What is normal for the industrial dairy industry, cannot automatically be accepted as normal for the RDM operation. Perhaps it is best that MPI go back to the drawing board and create a system that is safer and fair towards farmers, consumers and the raw milk movement. 

In addition, the Campaign for Real Milk posted a link to a government document published in 2003 on their homepage indicating that on a per-serving basis, deli meats are ten times more likely to cause food-borne illness than raw milk (Listeria Monocytogenes Risk Assessment: Interpretive Summary, Center for Food Safety and Applied Nutrition, Sept. 2003, page 17). Raw milk is not even on the list of the top ten most risky foods in North America, see IAFP Raw Milk Debate 2016.

 

Sources of diverse species, beneficial bacteria

In the SBS Insight episode of Gut Feeling Dr. Mosley recommended that we get more diverse species, beneficial bacteria. Where can we get these?

Probiotic yogurts? A new 2017 study show that most probiotic yogurts don't contain enough 'good' bacteria for additional benefits. The researchers found that the probiotic levels in these yogurts were sometimes up to 25 times lower than what clinical trials have found to be effective. 

Probiotic pills? Experts also say that the lack of actual live microbes makes commercial yogurts and probiotic pills an inferior probiotic, read more here. Also, who is to be the judge on which beneficial microbes will have the most benefit when science show it is the diversity that is the key?

Dr. Michael Mosley says that we have to culture our own microbes. He recommends culturing vegetables, making your own yogurt and your own kombucha.

Australian raw milk supporters would like to enjoy access to pathogen-free, regulated raw milk from animals like cows and goats. Some want to re'wild' their micro-biome. The human micro-biome project and other research shows that not having access to diverse species, beneficial microbes can be dangerous to the health of human beings. In this video, microbiologist Jonathan Eisen explains why good microbes may actually be our first line of defence against infection, disease, and lasting medical conditions. Research shows that most Australians do not have good gut health. Where are they going to find protection from pathogens in the food supply?

Sanitising our food supply is not the answer. We have to change our agricultural practises so that we have more ecosystems packed with good microbes, like the farm, the raw milk and the human micro-biome. That is good risk mitigation strategy.