Antibiotic resistance and food (again)

'Mission San Juan Capistrano bells'
by Ballookey Klugeypop under a
CC license

Antibiotic resistance is the case where microorganisms become able to survive after exposure to antibiotics. Antibiotic resistance is not a new phenomenon. When resistance to multiple antibiotics is observed in pathogens then things become particularly alarming. Infections by multidrug resistant pathogens (superbugs) are very difficult - and sometimes impossible - to treat, especially when the patient's organism is weak.

I've written on superbugs before but recently antibiotic resistance re-surfaced in the news in a different way. As described by Maryn McKenna, seafood imported from South Korea to Canada was found with Pseudomonas bacteria, which turned out to carry a gene that enables the synthesis of a carbapenemase enzyme.  This is alarmingly important for a number of reasons:

• Carbapenamase enzymes can inactivate carbapenem, an antibiotic of last resort.
• Seafood is sometimes mildly processed, in some cases deliberately to retain flavour and texture, while in others it may simply be undercooked. In such cases, the bacterium found would be likely to survive.
• Non-resistant bacteria can acquire antibiotic resistance from resistant ones via horizontal gene transfer involving plasmids

If consumed, the bacteria in question could possibly make it to the gut. As they are not pathogens they would not pose a direct problem themselves but they would be likely to transfer antibiotic resistance to the gut flora bacteria. I am not aware of the probability of such chain of events but should it happen in individual consumers, it would create inside them a population of bacteria resistant to a class of last resort antibiotics. That's not a good thing to happen!

Carbapenem resistance in the food production system has been a concern previously. Unfortunately, this needs to be considered in tandem with the occurrence of carbapenem resistant infections that seems to be on the rise in Europe (but still under control).

The Canada seafood case highlights a different route of concern, where the consumers may be exposed to resistant non-pathogens (with the potential to be found on a variety of foodstuffs) rather than resistant pathogens, directly, or antibiotic residues in food, which could - in turn - potentially invoke antibiotic resistance.

There is a need for better monitoring of the various routes that can lead to antibiotic resistance. This is no small challenge, though (and it comes with a certain price tag)! However, without any need to panic, it is essential we understand what the risk is and adapt our food processing (and healthcare) practices accordingly. Such approaches work on the prevention front. Hopefully, we'll also make some more breakthroughs on the antimicrobial front, as well!

Acrylamide: A shady side of yumminess

'Homemade freedom fries'
by sean dreilinger under
a CC license

EFSA has recently published a draft scientific opinion indicating concerns regarding acrylamide intake and its potential role as carcinogen.

If that is as alarming as it sounds, why don't we take action now to eliminate it from our food?

And, at any rate, what can we do about it?

The brief answer to the latter is that acrylamide is not easy to get rid off entirely, as is forms during common food processing, both at the kitchen level and the industrial level. But, yes, we can reduce it further by modifying the cooking and processing steps. "Brown it lightly, don't burn it" is the simple rule to follow!

The answer to the former, however, is a bit more difficult to give using hard data to back it up, because total acrylamide intake is normally rather low and there is not too much evidence on the effect of acrylamide consumption on consumers, yet. So right now, reasonable caution is the most prudent thing one can advise.

OK. If you are still with me and can bear with me for a little longer, here is the slightly more detailed version of the story...

Acrylamide is a chemical compound formed in starchy foods when they are heated at high temperatures, starting at low rates from about 120 ^oC,  for prolonged time. It is just one of the many products of the so-called Maillard reaction, which actually is a large set of reactions, that take place when amino acids (the building blocks of proteins) and reducing sugars are heated together. The Maillard reaction products contribute considerably to the brown colour and the characteristic taste and flavour of baked, grilled, fried, etc. products.

Most of the food-contained acrylamide comes from the consumption of potato crisps, fried potatoes and coffee. Other starch-containing food that have been subjected to high temperatures, such as rusks, bread, etc., also contain acrylamide but typically in lower (or much lower) concentrations. EFSA's draft opinion quotes a mean intake that ranges from 0.3 to 1.9 μg/kg body weight. Indicatively, smoking also adds to the acrylamide intake by 0.5 to 2  μg/kg body weight. Once consumed, acrylamide is metabolised either to N-acetyl-S- (3-amino-3-oxopropyl) cysteine or Glycidamide. It is mainly the latter metabolic product that raises the concerns for acrylamide's genotoxic and cancerogenic properties.

So how big is the risk?

EFSA follows the Margin of Exposure (MOE) approach. MOE is the ratio between the dose where no adverse effect is observed to the estimated human exposure. To estimate the risk level, MOE is compared with the product of the uncertainty factors that need to be taken into consideration. Those are factors applied to data obtained from animal studies and account for the various differences between species (taking into consideration safety factors, as well). In the current case of examining acrylamide's genotoxic and cancerogenic properties, EFSA calculated a MOE much higher lower than the product of the uncertainty factors, thus indicating concern.

Acrylamide production during food processing is not a new story. In fact, there are indications that acrylamide content has been reduced lately as awareness for acrylamide concerns increases.

Currently there is little evidence through human studies on any alleged effects of acrylamide. Evidence comes mostly from animal studies, where acrylamide's consumption effects have been observed. Such toxicological studies often study consumption regimes unrealistically higher than normal human intake, within non-typical diets. The latter implies that the ingestion of acrylamide is not accompanied by ingestion of other ingredients that may - in vivo - play a role in its actual effect. Despite those uncertainties, that doesn't mean that acrylamide concerns should be dismissed. Rather that caution should be advised and studying of the issue should continue.

In Europe, sampling and analyses for acrylamide content in food has been ongoing for several years now. Parallel to that, the food industry has been using an acrylamide "toolbox" in an effort to reduce acrylamide content in processed food. At the industry level, there is also the possibility to use different raw materials (less prone to acrylamide formation), enzymes (to break down or modify the protein content that contributes to acrylamide formation), etc. All those are steps towards the right direction and take place in parallel to the efforts to fully characterise the risk.

Acrylamide, as mentioned previously, also forms during cooking food at home. There, the rule of thumb is "Lightly brown it - Don't burn it!". Which goes together with the common sense advice to maintain a balanced diet with variety in the foods consumed.
 
Note: Various organisations across Europe have produced relevant FAQs or info-sheets. If you are in Europe, it's worth checking at your national Food Authority's website. E.g., BfR (DE), ANSES (FR), EFET (GR), FSAI (IE), FSA (UK), AECOSAN (ES), etc.

Dinner table: Food for thought

'Dinner table settings'
by joeywan under a CC license

For the part of the world that is lucky enough to have secured a minimum amount of food on a daily basis, the dinner table may feel like the reasonable place to end the daily routine.

In fact, though, the dinner table is much more than that. It's the place to talk with family and friends. It's the place to listen to others. It's the place to get to know people. It's the place for all emotions, from sorrow to happiness and from anticipation to excitement. It's the place to secure a deal, explore arguments, brainstorm on ideas, announce plans and... well... eat.

The latter, quite rightfully, sounds like stating the obvious. However, what I'm really trying to say is that, food-wise, the dinner table is challenging in many different ways. While, normally, we tend to focus either on the social dimension of eating or on satisfying the physical need to eat, getting things in order for a dinner table (or any meal, in fact) is not that simple a process. Indicatively, consider the following elements:

• General food safety; are the raw materials safe, has the food been handled properly, etc.
• Food allergens; is the food OK for the people that will consume it with respect to allergens, does one of them has an allergy on one of the ingredients used, is it likely to have allergens present through contamination, etc.
• Nutrition; does the meal provide what is needed for all its intended consumers, does it provide variety under the "balanced nutrition" rationale, etc.
• Special dietary needs; are they known for each of those consuming the meal, are cultural or religious-based dietary needs also considered, are they properly addressed altogether, etc.
• Acceptance; are the meal elements acceptable at the sensory level, i.e., do they look nice, do they have an appealing flavour and taste, etc.
• Novelty; is the meal intriguing or interesting for those who will consume it (not necessarily in the sense of 'food innovation')?

'Table' by anthimeria
under a CC license

Don't consider that list as exhaustive. It's not. Not even close. What is interesting is that each of the points above is close to being a science on its own.  And what is challenging is that for each of the points above there is still much to investigate and learn (at the scientific level).

Most of you will argue that although we normally eat on a daily basis in our lives the food we consume rarely causes problems. That is a fair point. But:

• The reaction of people to unsafe food depends on their overall health status and the factor that makes the food in question unsafe. Pathogens like listeria monocytogenes tends to be more of a concern for immunosuppressed individuals and pregnant women but there are food-borne pathogens that much more aggressive. Contaminants of chemical or biological nature may or may not lead to acute effects, depending on the type of agent, the amount consumed, etc. The impact of the consumption of unsafe food on human health and well-being in the long run is not always very easy to calculate. Besides that, most food-related incidents tend to be downplayed (e.g., an upset stomach or a single diarrhea incident is normally ignored) so the exact impact of non-safe food is likely under-estimated.
• Food allergy is not that rare. It 's impact on the individual depends on the level of sensitisation for the allergen in question and the amount consumed but in some cases it can be life-threatening.
• Good nutrition is a standing challenge. Nutrient needs vary depending on both genetic factors, age, health status, life-style choices and cultural background. Beyond that, there are people with special dietary needs, who need to abstain from certain ingredients or require more or less from specific ingredients. For instance, coeliacs must follow a gluten-free diet. To make things more complicated, the availability of each nutrient is a dish depends on several factors, including the nutrient form in the food, the food matrix (i.e., where is the nutrient contained), the presence of other ingredients (e.g., a nutrient may become partially "out of reach" to the digestive system in the presence of specific ingredients).
• Acceptance for both "normal" and "novel" foods is a relatively new niche for studies under food science. There is still a lot to learn on how people make choices for food and towards what result. It is not always the question of whether the food smells, tastes and "feels" good, though. Cultural background, habit or past personal experiences, amongst others, can make people like or detest certain foodstuffs.

I'm not suggesting or implying that the person who cooks dinner should get a food science degree. I'm merely pointing out that there is really a lot to learn for something many of us normally take for granted.

To eat or not to eat (it): The never ending quest for safe food

'Crystal ball take #1'
by Isobel T under
a CC license

Food safety has always been high on the agenda of state authorities, the industry and - of course - the consumers. Asking for the food we have access to to be safe is a reasonable expectation. One that sounds much easier that it actually is!

The more ingredients are employed in food production, the longer the route they follow before ending in a product, the more complex the food supply chain becomes, the higher the number of potential hazards. But, relax, that doesn't mean that the end-product will be unsafe. Practices are in place (and the EU those practices are dictated by law and enforced) to ensure that at any stage hazards are identified and controlled so that the final product is safe. Further to that, the Food Authorities operate sampling programmes and perform inspections so the overall risk is kept at very, very low levels. In fact, I suspect that the risk of consuming spoiled food due to improper storage or handling at home (or in mass catering establishments) may be an equally or more important factor to have in mind when discussing food safety!

Regardless of how things are at present, it is valid to say that a chain is a strong as its weakest link. With new players joining the food production and distribution 'arena', with an increasing globalisation that does have an impact on food production and on consumer trends, with the climate change very much in progress, with incidents of contamination of scale sufficient to affect the food chain, with the evolution of bacteria and other life forms that can affect food safety and quality and - altogether - with the emergence of new hazards, the quest for food safety is really still ongoing.

Still though, as every new food crisis proves, the system is not perfect. Could it ever be? I would say, plainly, no. Pardon my cynicism, but I feel it is impossible to check all food reaching the consumer for all potential hazards. And I mean really all potential hazards, regardless of whether they are considered to be reasonably expected, rather-not-expected or completely unpredictable. Oh yes, the last two are also seen for time to time. The sunflower oil crisis was something like that.

Performing an analysis on a foodstuff is normally restricted to a single hazard factor or - at best - at a limited group of hazards. The analysis for salmonella, for instance, will not highlight the presence of other pathogens, unless a specific analysis for them is also carried out, nor will it reveal high heavy metal concentration, even if that were the case. Currently, a long list of analytical methods is at hand to reliably identify the presence (and quantity) of numerous contaminants in food. But while for each used method attention has been put in ensuring specificity, accuracy, reproducibility, etc. there is no easy way in testing food samples for their safety altogether.

Is that critical? Well, maybe not yet. But it may well make sense in times of tight budgets. It may also prove useful as a line of defense against emerging hazards, including bio-terrorism. The latter sounds a bit exotic, true (although it's not entirely a new story). But it remains a concern and it's always better to be ready and alert! Going slightly off-topic, it seems that DARPA has been identifying a number of dark possibilities (some of which could also be deployed via the food supply channels) and tries to identify viable counter-measures....

Today, to my knowledge, there are no methodologies practically applied to indicate food safety altogether.

Sensory analysis can give hints on the state of foodstuffs but it would only detect hazards that would affect the sensory profile of the tested sample; the simple presence of many of the common food pathogens, the existence of chemical contaminants, etc., would normally go unnoticed.

Intelligent packaging advances have taken steps towards that direction (e.g., microbial growth indicators, time-temperature indicators, shock indicators, etc.) but their deployment has been limited, mostly because of cost issues.

A number of spectroscopy and imaging (e.g., hyperspectral imaging) techniques have been developed but they are indented for the measuring of quality parameters for specific foodstuffs, mostly where there is the necessary monetary driving force (e.g., meat quality estimation).

The combination of new-generation, biotechnology-produced sensors, employing cell membranes or living cells or enzyme-containing membranes also seem promising as analytical tools. They tend to exhibit specificity but, given their low cost, they could be assembled into kits suitable for a pool of tests on a single sample.

I believe that we should go much beyond that. We should keep existing analytical methods and work on improving specificity, sensitivity, etc. but we should also develop tools that would allow a first yes/no assessment of the safety of foodstuffs. I wouldn't be surprised if that would come together with a generous error margin, initially (false positive and false negative results).

Maybe we could get some inspiration from the IT world. Take spam filters applied to e-mails, for instance. They have been employing a number of technologies. Initially, they were looking for specific words in the subject line or in the e-mail text. Others were trying to evaluate the 'reputation' of the originating e-mail server, checking against public blacklisting databases. Nowadays, however, spam filters are much cleverer and more adaptable. They evaluate e-mails against a set of rules and the have the capacity to 'learn' as you (the user) re-classify false-positive messages that were incorrectly flagged as 'spam and false-negatives that ended up together with the normal e-mail.

Would it be possible to define a set of criteria that would allow a machine-learning system to be used for evaluating the overall safety of a food sample? For sure, deploying such a system at a world-wide level would give it a lot of data to use for refining its model (the 'learning' process). Would that make a good first line of defense? Could we devise cheap and effective methods to fill in any gaps that such a system would have?

The IT world has also been using other methods that may be of interest here. Computer viruses, for instance, have been sought for using a signature-search approach, initially. That has considerably evolved - as computer viruses became more complicated and the systems that they targeted also changed. Process emulation is one of the alternatives employed.

For the record, the spaceships of the Star Trek series were lucky enough to have 'biofilters' that could identify and remove 'anomalies' in the matter they were processing, including pathogenic agents.

Thinking aloud, I assume that the ultimate test would be systematic consumption and observation but - obviously - that is not an acceptable approach! Could we, perhaps, have an ecosystem of bacteria that could do that for us? Their survival, flourishing or decline, in other words the change in the balance of the ecosystem could give clues on the hazard factors present in the sample... Just a thought I feel it might be worth looking into....

The apple from the edge of the world

Eating an apple by Sean
Dreilinger under BY-NC-SA

On 1 October a warning was posted on the site of the Food Standards Agency (UK) advising food operators that shipments of apples imported from Chile have been found containing morpholine (at about 2 ppm) and that those apples should not be sold in the UK market. Similar advice was given by the food safety authorities across the EU and - where necessary - recalls where initiated.

In various places around Europe, the news piece got attention, as would happen with any news item related to food safety. In this particular case, however, the warning/recall/etc. drill from the food safety authorities is due to a legal reason rather than the appearance of a major threat for consumer safety: Morpholine (1-oxa-4-azacyclohexane) is a chemical used in a variety of applications. The major one is corrosion protection in water tanks and steam production systems. The morpholine molecule is amphiphilic making it also a good emulsifier. As such, morpholine can added in wax mixtures used by the produce industry in the coating of fruits like apples, citrus fruits, etc., making those easier to spread on the fruits.

Using various coating mixtures onto fruits, post-harvest, is a common practice. Such coatings hinder water evaporation and protect the fruit from various environmental factors, thus prolonging their shelf life. Fruits do have a natural water-repelling coating. Often, though, this gets damaged or remove by post-harvest handling. It's good to keep in mind that such coatings cannot make a fruit fresh; they just protect the freshness of the fruit.

The use of morpholine in wax coatings is not allowed in the EU, but it is permitted in other places in the world (e.g., USA, Canada, Chile, etc.). The EU has chosen the safe route here. The concern is not so much for morpholine itself, for which studies (examples here and here) do not indicate significant toxicity, mutagenic or teratogenic action, but rather for its nitrosated derivative that has been shown to be mutagenic and carcinogenic in lab animals. The conversion of morpholine to its nistosated derivative can be done in the body in the presence of nitrites. Even in the latter case, current risk analysis scenarios, as hinted in the FSA statement, suggest a very (very) small risk for the consumer. Peeling the apples would remove the risk factor altogether but - to be fair - plenty of consumers prefer eating them unpeeled; a normal rinse, would not affect the coating and would not remove its content.

As in every food safety discussion, voices calling for reviewing the handling of morpholine-containing wax-coated fruits have surfaced. After all, the food law is not necessarily a reflection of scientific findings. It's politics, too. It's very much a balancing game, where risk is on the one side and benefit on the other (and I'm talking about all kinds or risks and benefits, not just the ones about human health). Often, law makers take sides based on (their) common sense.

IMHO, not using a chemical that when ingested may pose a risk - no matter how inconceivably small - makes sense, especially when there is a list of down-to-earth, food grade compounds that could be used to achieve the same technological purpose (e.g., lecithin, fatty acid esters). Edible coatings may still be a rather active scientific niche but there are already proven formulations that could be used. Normal packaging materials could also be sufficient.

Going beyond the scientific/ technological discussion, I believe that for the food operator things are rather easy. Knowing what the law dictates is the way that their business will not be disrupted. Simply, that's the way to compete at the local level. I'm not saying that monitoring the food law across the globe is an easy task, although things have been slowly improving on that field: the EU and several other countries offer online access to legal documentation. Beyond that, there are officers that can be asked and professionals that they can help. In any case, such challenges are part of the global commerce game.