166 | Salmonella Deep Dive | Anatomy of a Wine Theft |
Plus, when turkeys attack
How Salmonella works;
Anatomy of a food crime;
Food Safety News and Resources;
Revenge of the turkeys (just for fun);
Food fraud news, emerging issues and recent incidents.
What is going on in South Africa? Hundreds of people sickened and dozens of children killed by what could be chemical poisoning by ?pesticides in food? (details are sketchy). It’s so alarming the government has declared a national disaster.
Hi, thanks for joining me in the world’s least-boring food safety newsletter.
In this week’s issue: how Salmonella works - specifically why it’s so effective at causing illness, and I unpack a sophisticated wine heist with a modus operandi that’s prompted warnings from a national food crime-fighting agency.
Also, since this is Thanksgiving week for those of you in the US (sorry Canadians, I missed yours last month), there’s a video featuring homicidal turkeys.
Find the South Africa poisonings news item in this week’s food safety news roundup (for everyone). For paying subscribers, there’s plenty of food fraud news this week, including an unusual incident involving nitrites.
Thanks for being here,
Karen
P.S. This week we welcome new subscribers from food safety training and auditing companies, a Norwegian food manufacturer, a food safety test kit supplier, and an ice cream maker from the South Downs of the UK. Welcome 👋 ‘Technical’, ‘Orders’, PM and Phil 👋, thank you for supporting my work.
How Salmonella Works
Ever wondered how Salmonella can grow in your intestines and cause illness when other bacteria can’t?
New research by the University of California - Davis Health has revealed a key piece of the puzzle and inspired me to find out more.
[Before we jump in, I’m going to use the words Salmonella (singular) and Salmonellae (plural) in a not-exactly-scientifically-correct way in this article, for the purposes of readability - sorry, not sorry!]
What is Salmonella?
Salmonella is a genus of bacteria that includes numerous species and subspecies. The two subspecies (technically referred to as serovars) most commonly associated with human gastrointestinal illness belong to the species Salmonella enterica, which is further divided into multiple subspecies and serovars based on their specific antigenic properties. They are:
Salmonella enterica serovar Enteritidis (Salmonella enteritidis)
Salmonella enterica serovar Typhimurium (Salmonella typhimurium)
Other serovars of Salmonella enterica (typhi and paratyphi) cause typhoid fever and paratyphoid fever, which are severe systemic illnesses with prolonged symptoms and life-threatening complications. Typhoid and paratyphoid fever most commonly occur in developing countries with inadequate sanitation.
For the remainder of this post, I’ll be talking only about non-typhoidal Salmonella, which is more commonly associated with foodborne gastroenteritis.
Salmonellae bacteria are typically found in the intestines of animals and humans. They can spread through contaminated food, water, surfaces, or by direct contact with infected individuals or animals.
Salmonella causes the third largest number of cases of foodborne illness globally, after norovirus and Campylobacter. There are approximately 1.35 million illnesses and 420 deaths from non-typhoidal Salmonella annually in the United States. In Europe, there were 66,000 confirmed cases and 81 fatalities in 2022.
How Does Salmonella Cause Illness?
Salmonella causes illness by invading and colonising the gastrointestinal system, including the small and large intestines. Here’s how we think it works:
Ingestion
The patient consumes food contaminated with Salmonella. Common culprits include raw or undercooked meat, poultry and eggs, unpasteurised milk and other dairy products, and raw fruits and vegetables.Invasion
Salmonella survives its journey through the stomach by using enzymes that consume protons through decarboxylation reactions that keep the pH inside its cells constant. It is thought to also have cellular systems that can actively repair cell membrane damage caused by acid exposure.
It has also been hypothesised that low-moisture, high-fat foods such as caramels and peanut butter have a protective effect, preventing stomach acid from coming into contact with Salmonella cells, and thereby assisting them to reach the small intestine unharmed.
Colonisation
Once past the stomach and inside the small intestine, the bacteria adhere to the lining of the intestinal wall to begin the process of colonisation.
Salmonellae have flagella (‘tails’) that are thought to help the bacteria penetrate the mucus layer inside the gastrointestinal tract to allow it to attach to epithelial (gut) cells.
Other foodborne pathogens that colonise the gastrointestinal tract include pathogenic Escherichia coli and Campylobacter jejuni. By comparison, Clostridium botulinum and Staphylococcus aureus are foodborne pathogens that do not colonise the gut but cause illness by producing toxins in food, with the toxins causing the illnesses, rather than the bacteria themselves.
Research published last week reveals that Salmonella can also evade the defences of ‘good’ gut bacteria which produce short-chain fatty acids that suppress the growth of pathogens. In the small intestine, Salmonella causes inflammation which disrupts the normal absorption of amino acids from food, changing the balance of nutrients in the gut.
The result is more of the amino acids lysine and ornithine in the gut, conditions which favour Salmonella, allowing it to survive the defence of the ‘good’ bacteria, so it can multiply in the large intestine (colon), which is its primary site of replication.
Salmonella can survive being engulfed by immune cells called macrophages, by ‘hiding’ within a membrance-enclosed vacuole (compartment). While safely inside the macrophages, the Salmonella cells cannot be detected or destroyed by other immune cells such as bacteria-killing neutrophils.
Replication
Inside the gut cells, Salmonella multiplies, causing damage to the intestinal lining, leading to symptoms like diarrhoea and abdominal pain.
Symptoms of Salmonella infection
Most Salmonella infections cause a condition known as salmonellosis, with symptoms appearing 6 to 72 hours after exposure. These include:
Diarrhoea
Abdominal pain
Fever
Nausea and vomiting
Headache
In healthy individuals, symptoms usually resolve within 4 to 7 days. However, severe cases can occur, particularly in young children, older adults, or immunocompromised individuals, where the infection can spread to the bloodstream or other parts of the body.
Serious side-effects and complications from Salmonella infections
Although many people recover from a typical Salmonella infection without long-term effects, some individuals can experience ongoing symptoms.
Reactive arthritis (Reiter's Syndrome) can develop post-salmonellosis. This occurs when the infection triggers inflammation in joints such as knees, ankles and feet. It usually resolves within a year.
Salmonellosis is thought to be a risk factor for irritable bowel syndrome (IBS), and dyspepsia, with people who experienced prolonged symptoms during an outbreak of Salmonella enteritidis more likely to develop IBS in the year afterwards, compared to a matched control group.
Invasive Salmonella infection affects about 8% of people who’ve had a confirmed case of salmonellosis. Invasive infections can cause meningitis, osteomyelitis and septic arthritis, which can be life-threatening.
Recovery from salmonellosis
While recovery from serious Salmonella-induced illnesses, like those mentioned above, can take months or years, a typical case of salmonellosis is self-limiting and usually clears within 7 days.
The body’s defences eventually defeat the bacteria and healing systems work to repair the damaged gut lining. As the lining repairs, inflammation reduces and symptoms such as fever and pain subside.
Antibiotics are used to treat severe cases of salmonellosis.
Final thoughts
As food safety professionals we spend a lot of time trying to prevent bacteria like Salmonella from getting into our food. However, we rarely take the time to learn about why certain bacteria are pathogenic while others do us no harm.
Salmonella has a suite of special characteristics that help it get through our stomachs to our intestines, where it can colonise cells and cause unpleasant symptoms, sometimes leading to more serious complications. Fortunately, most infections are self-limiting.
🍏 Read more: How Does Salmonella Get Into Seafood? (Issue 91) 🍏
Anatomy of a Food Crime
Wine theft revealed
Last month, the theft of a massive quantity of speciality English cheese made headlines around the world. It was perpetrated by someone pretending to represent a French supermarket chain and resulted in the loss of £300,000 worth of product. Four metric tonnes of smoked salmon were lost in a similar crime by another English company at around the same time.
When the cheddar cheese crime was reported, Stefan Hauser, a Swiss wine merchant came forward to share his story, revealing to British media he was targeted in a similar way in 2023, losing £52,000 worth of wines. The fraud nearly bankrupted his business.
“It’s really disgusting what they did to us” said Hauser.
The National Food Crime Unit (NFCU) of the United Kingdom is so concerned by the scale and sophistication of these frauds that it issued a special amber warning to UK food businesses and trade associations last week. Unfortunately, I’m not permitted to share the details of that alert, or even provide a link to it - I guess they want to avoid copycat crimes.
As with the cheese company, the wine merchant supplied the goods to someone claiming to represent a French supermarket and waited to be paid. The order was never paid for.
Both the cheese company and the wine merchant performed due diligence checks. The wine merchant looked up the name of the person who placed the order on LinkedIn and found a match for a person who works at a distributor for the supermarket. His bank checked the VAT and SIREN numbers of the purchaser and concluded the purchase looked legitimate.
It is alleged that the criminals behind the wine theft impersonated the real-life distributor, and supplied the VAT number and SIREN code of the legitimate company. The order, for 6,500 bottles of Pinot Noir, worth £52,000, was picked up by a legitimate haulier, taken to a warehouse in Paris and collected by another truck a few hours later.
The merchant believes the wines may have been taken to Russia where there is a black market for European wines.
… Believe it or not, there is also a black market for cheese!
Takeaways for food professionals
Food companies need to protect themselves from both losses to thieves and from accidentally purchasing stolen foods and ingredients.
Stolen food presents a food safety risk because criminals who steal food are unlikely to store or transport it correctly.
If your business is approached by a new buyer, do not reply directly to them, but contact the company they represent, using publicly listed contact details for the company, to independently validate the intended purchase.
If your business is offered high-value products by a new supplier, be wary of their provenance. Contact the brand owner directly to check whether the supplier is an authorised distributor.
In short: 🍏 Thefts of expensive consignments of foods and beverages are being perpetrated using identity theft and fraudulent ‘purchases’ which are never paid for 🍏 Food businesses are warned to be wary of such frauds 🍏
Main source:
Collins, D. and Dipesh Gadher (2024). Our 6,000 missing wines — and what we thought about Neal’s Yard cheese ‘heist’. [online] Thetimes.com. Available at: https://www.thetimes.com/uk/society/article/neals-yard-cheese-theft-more-luxury-food-companies-bc2bdfvg3.
Food Safety News and Resources
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When Turkeys Attack (Just for Fun)
Turkeys aren’t just tasty Thanksgiving meals, they are also vicious predators if this YouTube clip can be believed. Warning: this video is safe for work but comes with shoddy camera work and lashings of hyperbole.
Below for paying subscribers: Food fraud news, horizon scanning and incident reports
📌 Food Fraud News 📌
In this week’s food fraud news:
📌 Untargeted testing with GC-MS;
📌 False organic sugar;
📌 Mineral water, Mac & Cheese, seafood, honey, canned fish;
📌 Updates for fertiliser and more.
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