What must be done to get toxin out of Kenya’s food supply

Close-up of Aspergillus flavus and A. parasiticus producer of aflatoxins in corn.
KOOKLE/Shutterstock

Vivian Hoffmann, The International Food Policy Research Institute (IFPRI)

An exposé in Kenya has revealed that there are high amounts of a poisonous substance, known as aflatoxin, in many of Kenya’s popular maize flour brands. This is particularly worrying as maize flour is a staple food for most Kenyans. Part of the problem is in how maize is processed and distributed in the country. Vivian Hoffmann shares her insights on this and what must be done to prevent it.

What are aflatoxins and how do they get into our food?

Aflatoxins are toxic chemicals produced by a fungus, Aspergillus flavus. The fungus occurs naturally in soils, but under hot, dry conditions, it can grow and spread to a variety of crops. Maize and groundnut are two crops that are especially susceptible to contamination with aflatoxins.

While aflatoxin is a known carcinogen, and can be fatal to people in large doses, some of the other potential health impacts of consuming moderate amounts of aflatoxin over long periods of time are less well understood.

The amount of harvest that’s affected by aflatoxins varies each year, depending on the weather. Either too little rain during cultivation (which weakens the crops’ natural defences against fungal infection), or too much around harvest (which makes it difficult to dry the crops before storage), can lead to higher aflatoxin.

Poor plant nutrition is also a risk factor because, like drought conditions, it weakens crops and makes then susceptible to being colonised by fungus.

The fungus can continue to grow on crops if they’re not properly stored (and moisture gets in), or if they’re not well dried. In Kenya, maize stored by smallholder farmers has been found to be far more contaminated than purchased maize and is the most likely culprit for the outbreaks of aflatoxin poisoning that occur from time to time.

It’s not a uniquely Kenyan challenge. Aflatoxin contamination occurs in almost all countries. A non-exhaustive list of other aflatoxin hotspots includes the Southern US, Guatemala, parts of China, and India.

What is being done to try to address this issue and what’s not working

In Kenya, many food processing companies test inputs – like maize – before buying to avoid aflatoxin contamination in their products. But accurate testing is difficult because there is a lot of variation in aflatoxin across bags of maize, and even grains within a bag.

Under Kenyan law, maize that contains more than 10 parts per billion total aflatoxins, and groundnut above 15 parts per billion aflatoxin, cannot legally be sold. But testing procedures are not regulated.

On top of this, testing for aflatoxin at the factory gate doesn’t really solve the problem. When a consignment of maize or groundnut is rejected by one company, it is simply sold to a company with less stringent requirements, or on the informal market. This means the lowest-cost food is often the most contaminated, and people with the least to spend are at greatest risk of eating unsafe food.

In my ongoing research, I’ve found that a great deal of maize consumed in Kenya is never even tested for aflatoxin. This is because it’s either bought on the informal market, or consumed by those who have grown it.

Are there any steps that the public can take to avoid consuming them?

The International Food Policy Research Institute’s research on maize flour in Kenya has shown that more expensive brands are more likely to be compliant with the aflatoxin standard. Buying higher-priced maize flour is one way to protect yourself.

Also, if you grow your own maize or groundnut, dry your crops thoroughly while preventing contact with the soil, and store them in a clean, dry place.

Processed foods containing groundnut (also known as peanut) are usually more contaminated than whole nuts. This is probably because visibly damaged nuts are more likely to contain aflatoxin, and the best nuts are sold whole rather than processed. Grinding your own peanut butter from high-quality nuts is one way to avoid aflatoxin in this food.

Finally, one of the most important things you can do to avoid aflatoxin is to eat a balanced diet and avoid over-reliance on maize and groundnut.

What needs to happen next?

More resources are needed to deal with aflatoxin contamination at its root, which is on the farm.

The Kenyan government recently announced plans to spend Ksh 200 million on Aflasafe, an aflatoxin-control product that farmers apply to crops while they are still in the field. This is excellent news, but it’s extremely important that farmers are trained on how to correctly apply it for the treatment to be effective.

Other practices, including drying crops on plastic sheets, removing visibly mouldy or damaged crops prior to storage, and storing well-dried crops in hermetic bags, are also very effective at reducing aflatoxin. Plastic sheeting is available for around 400 KSh (about US$4) for a 15m2 piece, and can last multiple seasons, making it one of the most cost-effective solutions available.

There also needs to be a change in Kenya’s aflatoxin regulation to legalise the use of contaminated grain for specific non-food uses. The East African Standard for maize, which Kenya follows, requires all maize to meet the same aflatoxin limit, regardless of its use.

Since very little aflatoxin passes from feed into meat, crops that are considered unsafe for human consumption can be safely used as feed for animals to be slaughtered for meat. Many countries, including the US and EU members, allow higher levels – up to 30 times the Kenyan limit – in feed consumed by meat animals. Allowing food that exceeds the aflatoxin limit for human consumption to be fed to meat animals is a way to get this poison out of the food supply.

Vivian Hoffmann, Research economist, The International Food Policy Research Institute (IFPRI)

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Article in The Star is a shining example of how not to report on food safety

The Star newspaper published a feature article titled How safe is your sukuma wiki? in its 13 May 2019 issue. The article describes “an investigation by The Star” (?!) after “intensive testing” of samples of sukuma wiki (kale) from five open-air food markets and two supermarkets in Nairobi.

My initial reaction was: Since when did the Star’s journalists become food safety researchers?  Who exactly designed and carried out this study?

The article says that kale samples were collected from five open-air markets and two supermarkets in Nairobi and tested at the Kenya Plant Health Inspectorate Service and Analabs (a private laboratory) for the presence of heavy metals (lead, mercury, iron, copper and cadmium).

But who collected the vegetable samples? How many samples were collected in total? How many samples from each market? What analytical methods were used? In short: what are the details of the research design? The Star article does not say!

Surprisingly, despite these gaps, the article goes ahead to cite figures of mercury content in the vegetables. But the question is: how does one make sense of a statement like “the level of mercury in kales from Kariobangi market was 0.11 mg per kilo” [note, “mg per kilo” instead of the correct format mg/kg or parts per million] and yet there is no mention of or link to the research protocols?

Is the reported value of 0.11 mg/kg the mean mercury content of sukuma wiki from Kariobangi (n = ?) and if so, what is the margin of error? Were the reported differences in heavy metal contamination between markets statistically significant? Impossible to say with the information at hand!

Nonetheless, the Star article boldly declares that “you are better off buying sukuma wiki from your local market than at a supermarket” yet there is no credible empirical evidence leading to this conclusion!

Research conclusions are only as valid as the methods used to derive them. If the methods are questionable, the conclusions will not be valid.

This article by the Star is a shining example to media houses of how not to report on food safety research. Journalists should not purport to be food safety researchers. Journalism is journalism. Food science is food science. Food scientists carry out research and publish their research findings in peer-reviewed journals. It is the work of journalists to study and interpret those technical findings and report them in their newspapers a format that is easily understood by non-specialist audiences.

If the Star journalists had taken the trouble to search online, they would have discovered several recently published peer-reviewed studies on microbial and heavy metal contamination of vegetables in Nairobi. These studies have been led by scientists from the University of Nairobi, Kenyatta University, Jomo Kenyatta University of Agriculture and Technology, among other notable research institutions. The Star journalists should simply have reported on these research studies instead of creating their own “investigation”.

Dear journalists: You don’t just walk into Naivas and Nakumatt supermarkets and Gikomba, Githurai, Kangemi, Kariobangi and Marikiti markets, buy a bunch of sukuma wiki from each site, take your sukuma wiki bunches to a lab for testing of heavy metals and then report some “mg per kilo” figures as credible results of an “investigative report” on the safety of sukuma wiki sold in the city of Nairobi.

Your alarmist reporting may cause anxiety among some of your readers but you will not be taken seriously by those who understand what research design is all about.

Of hydrogen peroxide in hawked milk and fake yoghurt

Last month (April 2016), the subject of milk safety featured in the print media yet again with two interesting reports from Nakuru County.

In the first case, unscrupulous milk traders and hawkers were reportedly adding hydrogen peroxide to raw milk in an attempt to prolong its shelf life [a somewhat jua kali attempt at reactivating the lactoperoxidase system, a recognized method of extending the shelf life of raw milk for up to 8 hours that is promoted by FAO where cooling of milk is not feasible though not authorized for use in Kenya].

In the second case, the Ministry of Health reportedly busted a syndicate involved in processing, packaging and sale of ‘fake’ yoghurt (‘fake’ because it apparently did not contain any milk but was made from a cornflour base).

The Kenya Dairy Board has consistently waged war against informal sector milk hawkers and traders, branding the milk they sell as “unsafe” and calling on Kenyans to opt for “safe” processed, packaged milk from the formal sector.

Well, these two recent incidents from Nakuru serve to illustrate one key research finding from the International Livestock Research Institute:

Raw milk sold in the informal sector is not necessarily unsafe and processed, packaged milk sold in the formal sector is not necessarily safe.

These incidents also reinforce the importance of adopting a holistic, risk-based approach to the management of milk safety, regardless of whether the product is sold in the informal or formal sector.

The key questions to be tackled are: what are the risks associated with the milk and what actions should traders/processors/consumers take to reduce or eliminate the risks and thus ensure milk safety?

These questions should be answered in a systematic way within the framework of risk analysis which involves three main activities: risk assessment, risk management and risk communication.

Training is an important component of risk management and it’s encouraging to note that the Kenya Dairy Board has said that it plans to train hawkers countrywide on milk safety and issue them with licences to sell milk.

Some may question the capacity of the Kenya Dairy Board to implement such a program sustainably but it is a step in the right direction.

I’ll keep watching the media space for more developments.

Daily Nation article on toxins in Nairobi foods raises more questions than answers

Today’s Daily Nation (11 Jan 2016) features an article entitled Tests show dangerous levels of toxins in foods sold in Nairobi. My immediate reaction upon reading the article was, quite frankly, disappointment at the shallow coverage of such an important topic as food safety. In fact, the article as it stands is quite alarmist and has a lot of loose ends.

I expected the Daily Nation article to be based on research evidence published in a peer-reviewed journal so I hoped there would be some mention of where the research was published or, at the very least, a link to the study. Alas! No such reference was provided.

By providing information on where the research was published [assuming, of course, that it was indeed published in a peer-reviewed journal], an interested reader would be able to cross-check the details and delve further into specifics of the research protocol, such as, how the sampling was done, the specific analytical tests and so on.

One would then be able to conclude whether the tested food samples were representative (results of the sample can be generalized to the entire population of milk, vegetables, fruits etc. sold in the whole of Nairobi, for example) or non-representative (in which case the results would be specific to the market, supermarket or residential estate from which the samples were collected).

The headline [Tests show dangerous levels of toxins in foods sold in Nairobi] suggests that tests were carried out and the results showed that levels of specific foodborne toxins were “dangerous”. However, nowhere in the article are the levels of the foodborne toxins mentioned.

In fact, one may be tempted to ask: What is a ‘dangerous’ level of a foodborne toxin as opposed to a ‘non-dangerous’ level of the same? If the levels of the toxin are not quantified and reported, then how do we know they are ‘dangerous’?

Sub-editors, who are responsible for writing headlines of newspaper articles, would do well to stick to the facts of the story and avoid such alarmist headlines. That said, the story itself needs to cover the facts adequately.

Instead of providing details of the levels of foodborne toxins found, the writer merely cites six professionals who mostly comment on the negative health impacts of some chemical hazards.

It’s not readily clear if these six individuals were part of the study (or studies) that tested the various samples of food products or if the writer was only interested in capturing expert opinions, perhaps to lend an air of credibility to the story.

A statement like “To make matters worse for Nairobi residents, non-packet milk sample tests by Kenyatta University nutrition students revealed higher-than-recommended amounts of hydrogen peroxide — used as a preservative — and formalin, also used to preserve bodies in mortuaries” is not very helpful from the risk communication point of view and is actually quite alarmist, not least because we don’t have the full information on the research protocol that the students used.

Clearly, the Daily Nation writer and sub-editor chose to angle this story with a focus on hazards rather than on risks.

However, if you look for hazards in food, you will find them. Hazard-based approaches to food safety management have since paved way to risk-based approaches which are more pragmatic.

Likewise, when food safety communication focuses on risks rather than on hazards, the focus is more on what actions consumers can take in order to reduce or eliminate foodborne risks.

In this way, one is able to avoid the often alarmist, hazard-based reporting which invariably has the effect of leaving consumers overly anxious and even scared of eating certain food products.

Food safety: The theme of World Health Day 2015

World Health Day is celebrated on 7 April every year to mark the day when the World Health Organization was founded in 1948. Each year, a theme is selected to highlight a priority area of public health. This year, the global theme was food safety, with the slogan “From farm to plate, make food safe”.

On World Health Day 2015, The Standard carried a two-page supplement by the Ministry of Health to create awareness on the four most common foodborne diseases in Kenya: cholera, typhoid, aflatoxicosis and brucellosis.

             

Later, the Sunday Nation carried a vox pop feature in its Young Nation section that is targeted at children. I was quite pleased to note that the pupils who were interviewed seemed to be well aware of how to ensure that the food they eat is safe.

Food poisoning incident at Strathmore University leaves 25 hospitalized

On Wednesday 25 March 2015, The Standard reported an incident of food poisoning at Strathmore University following a dinner organized for Fourth Year students the previous Friday at the university’s auditorium. There were 80 reported cases and 25 students were hospitalized. Catering services had been outsourced for the event and the university reported that investigations had been launched to establish the cause of the food poisoning.

The university had earlier issued a status update on the incident via Twitter:

STATUS UPDATE: Official Communication from Strathmore University http://t.co/N57BxRq4zQ #StrathmoreUniversity pic.twitter.com/CU5yeDCjnT

— StrathmoreUniversity (@StrathU) March 24, 2015

The Daily Nation story was more detailed and included interviews with some of the hospitalized students as well as a doctor at Nairobi West Hospital who attended to some of the affected students.

However, neither report mentions the name of the catering service provider. This incident would make for a very useful case study.  It would be very interesting to trace the actual source of the contamination. It’s a pity that we don’t have comprehensive documentation of food contamination cases in Kenya.