Monday, June 19, 2017

Would you eat transgenic food?

Many readers will immediately respond to the title of this post with a resounding "NO".

Don't be so hasty!

Looking close to home, we find that our own bodies contain many foreign genes.  It is estimated that around 8% of the human genome consists of fragments of endogenous retroviruses - about 100,000 of them.  Not all of these fragments are "junk" (a term the popular press is rather keen on).  A number of viral genes have been co-opted for our own purposes, in gene regulation, production of transfer RNA and ribosomal RNA.  One viral gene is critical to the formation of the placenta.  

On this basis, I'm not too surprised to read a piece of research* that shows that some of our vegetable crops are naturally transgenic.  Cultivated sweet potatoes contain the transfer DNA sequences from a bacterium called Agrobacterium.  This genus naturally infects the roots of certain plants, causing a nodule or hairy roots.  This T-DNA is not present in the wild type sweet potatoes, implying that one or more traits carried on this piece of DNA were selected for during the domestication of the sweet potato.

The authors of the paper point out that sweet potatoes have been consumed for millennia, and that this "may change the paradigm governing the “unnatural” status of transgenic crops."

If we look further, in my opinion, it is almost certain that we will find other bacterial or viral genes in our fruits and vegetables.


* The article is technical, but you can find it online

The genome of cultivated sweet potato contains Agrobacterium T-DNAs with expressed genes: An example of a naturally transgenic food crop



www.pnas.org/cgi/doi/10.1073/pnas.1419685112 

I originally published this article in 2015 on the NZIFST blogspot:  http://nzifst.blogspot.co.nz

Friday, June 9, 2017

Hand washing is REALLY important

According to a post on Stuff, a worker at a Silver Fern Farms meat plant in New Zealand lost her job for not washing her hands.

At first sight, this may appear to be a draconian decision, but the company had written procedures in place, stating that if a worker touched dropped meat, they should wash their hands before handling other meat being prepared for packaging.  Meat that has fallen onto the floor can be contaminated by many different bacteria and by other organic material.  Handling this fallen meat and the area around the dropped meat table could contaminate the worker's hands and hence other meat being packaged.

If the worker had been properly inducted into the plant, she would have been made aware of the requirement to wash hands after retrieving meat from the floor and transferring it to the dropped meat table.

The real problem is that the company has a meat export licence that almost certainly has stringent hygiene requirements incorporated.  Thus failing to observe the written procedures in relation to dropped meat could have put the licence, and the livelihoods of all other workers at the plant, at risk.