Michael Stephen Column Uncategorized

Bags of bacteria, home composting and Oceana (FREE)

Today Michael talks about “Bags of bacteria; ” Products marketed as home-compostable; and Biodegradation in the Oceans. This is a FREE article


I have been reading a university study

Microbiological contamination of reusable plastic bags for food transportation which has convinced me that all durable plastic bags used for carrying food should be made with an anti-bacterial masterbatch see www.d2p.net

The researchers say “Nowadays, with so many concerns for the environment, the use of reusable plastic bags is becoming routine, instead of the use of single-use plastic bags. However, this is controversial in terms of food safety, since consumers transport many different foods which could contaminate their bags, and pose a risk to their health due to cross-contamination.

This study aimed to detect pathogens from 30 used reusable polypropylene bags and, to evaluate their antibiotic resistance profiles after identification by 16s rRNA of each isolated microorganism. Several genera of Enterobacteriaceae, coagulase-negative staphylococci and also Listeria monocytogenes were found in the reusable plastic bags.

In general, high percentages of antibiotics resistance were found, highlighting the elevated occurrence of multi-resistant isolates of coagulase-negative staphylococci and Enterobacteriaceae. No correlation was found between microbial levels and the visual appearance of each bag, demonstrating that appearance is not a reliable indicator of bag contamination.


An American company called Storopack have been advertising their air cushion film, “AIRplus® BIO Home Compostable.”

They say it reduces plastic waste by closing the natural cycle because it can be disposed of alongside organic waste on home compost heaps. It is certified in accordance with EN 13432, but this standard requires the material to convert into CO2, not into compost. I don’t see how this reduces plastic waste – it actually promotes waste by turning the material into CO2 gas, which promotes climate change but does nothing for the soil. Garden waste is compostable because it converts into compost, but plastic does not. I don’t think that plastic of any kind has any role to play in the composting process See Composting

As to home-composting – on 2nd December 2022 the UK Environment Minister said: “HM Government notes the findings from UCL’s study into the home composting of plastics. The study has shown that home composting is not a viable destination for managing plastic waste.” 

Storopack is also proudly distancing itself from “misleading labels and plastic products featuring oxo degradable additives, which are not really compostable, but merely disintegrate so as to become invisible, leaving behind microplastics.”

They clearly don’t understand the subject, and should in fact be making their air-cushions oxo-biodegradable, so that they don’t need to be taken to a composting facility, and can be recycled if collected.  Oxo-degradable plastics degrade by oxidation but do not biodegrade and therefore create microplastics.  These are ordinary plastics, which don’t contain a prodegradant catalyst.   By contrast oxo-biodegradable plastics do contain a prodegradant catalyst and convert rapidly into biodegradable materials, so they don’t create microplastics.  They don’t pretend to be compostable, and are designed instead to biodegrade in case they escape into the environment as litter.  See Why biodegradable?


I do not normally agree with this NGO, as they talk about oxo-biodegradable plastic without understanding it, and they don’t know the difference between oxo-degradable and oxo-biodegradable. They are therefore doing the oceans more harm than good.

They have however published some recent research at Bioplastic remains plastic  which shows that plastics such as PLA and PBAT do not properly biodegradable in the ocean.

By contrast, a four-year study sponsored by the French government showed that oxo-biodegradable plastics “biodegrade in seawater and do so with a significantly higher efficiency than conventional plastics. The oxidation level obtained due to the d2w prodegradant catalyst was found to be of crucial importance in the degradation process.” The Marine Environment 

Michael Stephen

Michael Stephen is a lawyer and was a member of the United Kingdom Parliament, where he served on the Environment Select Committee. When he left Parliament Symphony Environmental Technologies Plc. attracted his attention because of his interest in the environment. He is now Deputy Chairman of Symphony, which is listed on the AIM market of the London Stock Exchange, and is the founder and Chairman of the Biodegradable Plastics Association.

Earlier Postings in this Column

All articles from Michael Stephen

Interview with Michael Stephen

Questions and Answers on OXO-Biodegradability


The opinions expressed here by Michael Stephen and other columnists are their own, not those of Bioplasticsnews.com

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