At what levels are microorganisms poisonous?
Hello all,
I am looking for a good source for at what levels microorganisms are becoming dangerous for food safety.
Our products (seeds and kernels) have a natural low AW value so they do not support the growth of microorganisms and are traditionally only used in the bakery industry.
But now the products are used for other purposes and we are getting more questions about microbiology.
There are so many different limits but I cannot find when the microorganisms become poisonous and not fit for consumption.
for example Bacillus Cereus for our products
- EU legislation -> No limit
- Dutch legislation -> 100.000 cfu/g
- German workgroup who set limits for micro in food -> 1.000 cfu/g
- Customer request (example) -> 10 cfu/g
Legislation is ofcourse leading, so when supplying to The Netherlands the limit would be 100.000 cfu/g but if the customer request is 10 cfu/g we need to find a middle.
This made me wonder at what levels are the microorganisms become poisonous and not fit for consumption.
Is there a source for this?
Well..the real answer is "It depends". "Poisonous" is really a vague term. What may be poisonous to one is not poisonous to another. As an adult male weighing in at 250 pounds (110 KG) poisonous to me is far less likely than my 3 year old child.
If you want to be conservative you go with the lowest limit that's set for you, either by regulatory or your customers. In almost all cases customers will have lower limits and demand more stringency with microorganisms. If you can meet those limits then use those. In any verification / validation activities reference the regulatory limit, but operate at the customer limit.
If there are no limits for your target microorganisms then you'll have to work on validating your own limits if they are microorganisms of concerns for your products.
The infective dose for 'microorganisms' will change hugely depending on the specific microorganism and the host, and I'm no microbiologist but I'd imagine there are a wide range of variables and conditions that also have an impact.
Meeting legal requirements is priority of course, and the customer's guidelines are often more strict and the 'target'. However if a customer has set parameters that cannot realistically be met you need to have a discussion with them. Continuous rejection of stock due to micro failure (as per their limits) is not going to help anyone.
There will be a multitude of sources and literature on microorganisms and food poisoning but you'd need to define your search really since the topic as a whole is so broad.
Hello all,
I am looking for a good source for at what levels microorganisms are becoming dangerous for food safety.
Our products (seeds and kernels) have a natural low AW value so they do not support the growth of microorganisms and are traditionally only used in the bakery industry.
But now the products are used for other purposes and we are getting more questions about microbiology.
There are so many different limits but I cannot find when the microorganisms become poisonous and not fit for consumption.
for example Bacillus Cereus for our products
- EU legislation -> No limit
- Dutch legislation -> 100.000 cfu/g
- German workgroup who set limits for micro in food -> 1.000 cfu/g
- Customer request (example) -> 10 cfu/g
Legislation is ofcourse leading, so when supplying to The Netherlands the limit would be 100.000 cfu/g but if the customer request is 10 cfu/g we need to find a middle.
This made me wonder at what levels are the microorganisms become poisonous and not fit for consumption.
Is there a source for this?
With respect to yr example, B.cereus is "poisonous" due to its production of a chemical toxin in foods and/or internally. The toxin is not likely to be produced in food until the B.cereus bacterial level exceeds a certain threshold, IIRC in the 105 - 106 cfu/g range. Consequently any inputs which are considered potentially contaminated with B.cereus typically have specifications using max. B.cereus bacterial levels set well below this threshold, eg 102cfu/g. Details here -
Bacillus cereus.pdf 96.2KB 17 downloads
Countries may vary in the specific quantitative numbers chosen for safety.
Other microbial species may be "poisonous" due to the bacterial species itself and it's effect on internal organs of the body after consumption.
Some species may be "poisonous" at very low levels in food such that they are classified as zero-tolerant species, eg Salmonella
Etc.
I believe one popular source of general information on "poisonous" characteristics is the FDA's Bad Bugs Book.
Bad-Bug-Book-2nd-Edition-(PDF).pdf 3.25MB 25 downloads
(300 Pgs of light reading :smile:)