3 replies to this topic

[Milos Vasic]

Dear all
We are importers of grain products like flax seed, pumpkin seeds, sunflower kernels...
We have from time to time problem, that microbiology tests on goods that we import show presence of lipolytic bacteria. Since by new legislation we are not obliged to do this analysis I would like to know if this bacteria is real threat and in what number so that I know to insist that we do this analysis?
Most of product is used for roasting and baking on high temperatures but some is consumed raw as we import.
Thanks in advance

[DP2006]

Milos,

A potential problem with the lipolytic bacteria is breakdown of the oils in your products due to the action of the lipase enzymes in the bacteria. This can give rise to "off-flavours" eg soap like taste (depending on the type of oil present).

Although you might not have the answers, some points to consider are:-

• Flavour of seeds with presence of lipolytic bacteria - How does the taste of these compare to "normal" seeds? Does this change over the storage (shelf-life of the product?)
• Quantity of broken seed - Any bacterial lipase activity is likely to be highest if the seeds have oil on the surface or there are broken seed. Do you specifiy a maximum limit for broken seed or are you separating these out?
• Heat - Heat treatment eg roasting is one way to deactivate the lipase enzymes that could cause off-flavour.
• Storage conditions - Rate of off-flavour production could be affected by storage conditions eg temperature, humidity.

If there is a potential problem for production of off-flavours, this is most likely if you have product that contains broken seeds and that is eaten raw ie without heat treatment. A storage trial should help assess this.


I assume the lipolytic bacteria are not a problem from a food safety viewpoint ie I assume they are not food pathogens?

Hope this helps!

Good luck.

DP2006

[Milos Vasic]

Problem with lipolytic bacteria is that sometimes when we import grains like flaxseed, sesame seeds, pumpkin seeds, nuts etc which all have relatively high amount of oil inside. Lypolitic bacteria can be present and no off taste can be detected. We have possibility to separate broken seeds but problem is that seeds are sampled raw on the border so problem can occur before material reaches our facility. In my experience roasting will inactivate lipase but off taste will be enhanced. All that I have heard up to now is that lypolitic bacteria can cause diarrhea.
However some of custom inspectors when they do the tests of material entering country insist that there should be no bacteria present( although I think they are natural inhabitants on the raw seeds that I mentioned)? Did anyone had problem with this type of bacteria also?

[DP2006]

Milos,

Regarding the possible link with diarrhoea / diarrhea, what lipolytic bacteria are you testing for?

Natural products of the types you are using will have their own bacteria present. It is not realistic for anyone (including customs inspectors) to believe that the product will be free from all / any bacteria.

I don't know what country you are importing into but the important point is that if the customs inspection specifies limits for certain types of bacteria that your imports meet this requirement. Have they provided you with any guidelines on specific bacteria that you should test for?

DP2006