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Published Date: 2017-05-25 10:04:04

Subject: PRO/EDR> Botulism - USA (10): (CA) nacho cheese, type A toxin, unrelated 2nd death

Archive Number: 20170525.5060186


A ProMED-mail post


ProMED-mail is a program of the

International Society for Infectious Diseases


Date: Wed 24 May 2017 1:17 pm PDT

Source: The Mercury News [edited]


The country's foremost researchers on botulism in dairy products are calling the recent [botulism] outbreak at a gas station in Walnut Grove a "perfect storm" of circumstances that left one dead and 9 sickened.

"Botulism in cheese products, including processed cheese, is extremely rare," said Eric Johnson, professor in the department of bacteriology at the Botulinum Toxins Laboratory at the University of Wisconsin. "Outbreaks of botulism in commercially processed cheese during the past 50 years is extremely rare and can be counted on the fingers of one hand."

Although extremely rare, Northern California has seen 2 deaths from foodborne botulism in the last few months. Within the last month, Napa County has had 1 death from botulism related to canned goods, according to county health officials. Since 1950, the USA has seen 3 instances of human botulism outbreaks due to dairy products. In all, 46 people were affected and 2 died. The most recent was in 1993 where a commercially canned cheese sauce was contaminated after it left the factory and sickened 8 people, killing one.

"We want to remind people to properly store canned goods they purchase and if they are canning themselves to follow recommended home canning and preserving procedures so you can ensure as best as possible the safety of your canned goods," said Cara Mae Wooledge, public health education specialist for Napa County Public Health. Wooledge reinforced that anyone experiencing symptoms of botulism poisoning, blurry or double vision, nausea or drooping eyelids, should contact their healthcare provider immediately. Before these incidents, there had only been 1 death from foodborne botulism in the state of California in the past 2 decades, according to CDC data.

On 28 Apr 2017, the Los Angeles County Public Health Department issued a warning to residents about a deer antler tea product after one confirmed and one suspected case of botulism. The tea was recalled.

The California Department of Public Health has said that an open 5-pound bag of Gehl's Jalapeno Cheese Sauce confiscated from the Valley Oak Food and Fuel station tested positive for the botulism toxin. Gehl Foods' CEO Eric Beringause released a statement saying that "Gehl's facilities remain safe for food production and all of our food samples continue to test negative for any contaminants. There is no recall of Gehl's nacho cheese product."

Johnson, along with his colleague Kathleen Glass have devoted their lives to studying how to prevent botulism from growing in cheese. Glass, the associate director of the Food Research Institute, received her doctorate in the topic and has co-authored numerous papers on the subject with Johnson. Both have spent decades working out the right combinations that prevent the bacterium, _Clostridium botulinum_, from surviving or growing in cheese.

Gehl's cheese is in liquid form and is not pasteurized, but undergoes an "aseptic process," which kills bacteria. The cheese has a shelf life of 12 months, but must be kept above [140 deg F/60 deg C] after opening and the dispenser must remain plugged in. "If the package is unopened, it is basically sterile. If it's refrigerated, (the bacteria) can't grow. If it's kept above 140 deg F, it can't grow," Glass said. "This was just an alignment of the planets that must have recontaminated it and held it at the right temperature for a long time for it to grow... It's really the perfect storm."

Botulism is found everywhere, but sickness from the toxin the bacterium produces is rare and mostly affects infants. Botulism among adults is even rarer. Foodborne botulism is rarer still. Due to the rarity, there is a chance that the descending paralysis is misdiagnosed for Guillain-Barré syndrome, a stroke, or other medical conditions that lead to muscle weakness.

Although it is sometimes used in medicine to treat muscle spasms or in cosmetics to treat frown lines, the botulism neurotoxin is one of the most potent and lethal substances in the world. The substance, which can fatally paralyze victims, is so dangerous that it is listed as a Category A bioterrorism agent by the CDC. Iraq was said to have produced 19 180 liters of concentrated botulinum toxin in the 1990s, according to the UN Security Council. Less than one-millionth of a gram is enough to kill the average adult.

The type A strain of botulinum toxin found in the nacho cheese is the same type that is cultivated for biological weapons. There is no antidote for botulism intoxication, but early use of an antitoxin can lessen the effects of the paralysis. Although symptoms can take anywhere between 6 hours and 10 days to appear, Johnson stated that ideally, the antitoxin should be administered within hours of eating the food to prevent the onset of paralysis. The need for a rapid response is critical in treating any cases of botulism, which is why every case is treated as a public health emergency. After the initial hospitalization on 22 Apr 2017, health officials were able to identify the source 13 days later and prevent further sale of the nacho cheese product at the Valley Oak Food and Fuel.

State health officials will not release which counties have reported cases of botulism, citing patient confidentiality. Sacramento and San Joaquin counties have confirmed cases in their counties and Napa County officials have confirmed one botulism case unrelated to the nacho cheese outbreak. Solano County health official Jayleen Richards would neither confirm nor deny any reported cases of botulism in the county.

[Byline: Aaron Davis]


Communicated by:



[This posting underscores the rarity of cheese-associated botulism as well as confirms that the serotype of the toxin was indeed type A, the type that tends to be the most severe in degree and length of illness. The antitoxin used cannot neutralize toxin already bound to neural toxin.

This posting also alludes to a 2nd death in California, a case of botulism related to home canning and not related to the nacho cheese-related cluster. It is not stated what home-canned food was involved or whether there were other non-fatal cases.

Botulism toxin has its effect at the neuromuscular junction. Mechanistically, when a motor neuron action potential depolarizes the axon terminal, acetylcholine is released from the cytosol into the synaptic cleft. When botulinum toxin (BT) is exposed to the neuromuscular junction, the heavy chain of the botulinum neurotoxin binds to glycoprotein structures specifically found on cholinergic nerve terminals. This specific docking is the reason for BT high selectivity for cholinergic synapses.

After internalization, the light chain of the botulinum neurotoxin binds with high specificity to the SNARE protein complex. The target proteins vary among the BT serotypes. BT-A cleaves synaptosomal-associated proteins of 25kDa (SNAP-25). BT-B cleaves vesicle-associated membrane protein (VAMP), also known as synaptobrevin II. - Mod.LL

A HealthMap/ProMED-mail map can be accessed at: http://healthmap.org/promed/p/18147.]

See Also

Botulism - USA (09): (CA) gas station food, nacho cheese conf, fatal 20170523.5056161

Botulism - USA (08): (CA) gas station food, nacho cheese 20170519.5047996

Botulism - USA (07): (CA) gas station food, nacho cheese 20170512.5031065

Botulism - USA (06): (CA) gas station food, RFI 20170508.5021002

Botulism - USA (05): deer antler herbal tea, FDA recall 20170507.5018201

Botulism - USA (04): (CA) deer antler tea 20170429.5003486

Botulism - USA (03): (TX) wound, drug-related, 2005-2015 20170427.4999639

Botulism - USA (02): (CA) satay, risk, recall 20170420.4982801

Botulism - USA: (CA) wound, non-drug-related 20170402.4942916



Botulism - USA (11): (NM) wound, drug-related 20161004.4535918

Botulism - USA (10): soups, risk, recall 20160911.4480731

Botulism - USA (09): (NM) wound, drug-related 20160716.4350262

Botulism - USA (08): vacuum packed fish, risk, recall 20160623.4302950

Botulism - USA (07): (MS) prison brew 20160615.4288676

Botulism - USA (06): (NY,CA) dried salted uneviscerated fish, risk, recall 20160426.4184418

Botulism - USA (05): vegetable soup, risk, recall 20160421.4174551

Botulism - USA (04): (WA) fatal, conf 20160302.4062476

Botulism - USA (03): (OH,CA) jarred pesto, 2014 20160227.4052791

Botulism - USA (02): (WA) fatal, RFI 20160221.4037933

Botulism - USA: (MN) uneviscerated fish, recall 20160115.3935285


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