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Antibiotics

Drugs and Superbugs

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Microscopic image of Klebsiella Pneumonia

Since the discovery of Penicillin, nearly 100 years ago, antibiotics have been used in medicine and allied industries in the fight against disease causing bacteria. Sadly due to our excessive and uncontrolled use of these substances, bacteria have begun to resist antibiotics, the dawn of the “superbug”.

Superbug is a term used to describe bacterial strains that have developed an immunity to multiple antibiotics that can no longer kill them [1]. Some of these superbugs include multi-drug- resistant tuberculosis (not transmitted through food) and an emerging food pathogen Klebsiella pneumonia, a major cause of pneumonia.

Although not commonly categorised as a food borne pathogen, Klebsiella pneumonia has emerged as a contaminant in a number of studies in the US on retail meat and poultry. These respective studies showed that 14% of Chicken samples and 47% of meat samples tested contained the pathogen. Even more alarming is that 8.5% of the Klebsiella pneumonia were multi- drug resistant. These studies also showed startlingly high levels of drug resistance among Salmonella (38%) and E.coli (40%) isolated from these meat samples [2].

In South Africa numerous studies have been done on bacteria isolated from cattle and poultry that have shown many of these to be resistant to at least one antibiotic. Notably, resistance to Avoparcin, which has been banned since the early 90s was found in 66% of E.coli isolates from poultry in a study conducted in 2002. Avoparcin was banned internationally due to its close relations to Vancomycin, a last line of defence against multiple drug resistant bacteria [3].

The regulations governing the maximum limits for veterinary medicine and stock remedy remedy residues (R. 1809 of 1992) governs the use of antibiotics in livestock in South Africa. These regulations have been written with the intension of regulating the maximum allowable levels in food consumed by the consumer and are not aimed at controlling the use and abuse of antibiotics by the producer. Apart from treating disease, it has been common practice in South Africa to use antibiotics as a prevention against disease and as growth promoters [3].

Studies have shown that over time bacteria are able to build up a tolerance to these low levels of antibiotic, acquiring and transferring these resistance genes amongst each other. The cattle and their manure become major vehicles for transferring these resistant bacterial strains to farm personnel [4]. Further human-to-human contact spreads the bacteria and their resistance genes along with them. In other cases the cattle are slaughtered and the resistant bacteria are passed onto the consumer via the meat.

In light of this, although regulations are in place to control maximum residue limits of antibiotics in meat and poultry, it is the responsibility of the producer to be due diligent. Farmers would do well to consider the implications of using antibiotics, except for the treatment of disease.

Article by: David James Scott

References:
1. National Institutes of Health, News in Health 2014. Stop the spread of Superbugs: Help fight drug-resistant bacteria. Available from:<https://newsinhealth.nih.gov/issue/ feb2014/feature1>. [12 Feb 2016].
2. Consumer Reports, Product Reviews 2014. Dangerous contaminated chicken. Available from: <http:// www.consumerreports.org/cro/magazine/2014/02/the-high- cost-of-cheap-chicken/index.htm>. [12 Feb 2016].
3. Henton, M.M. Eagar, H.A. Swan, G.E. van Vuuren, M. 2011. Part VI. Antibiotic management and resistance in livestock production. SAMJ 101(8).
4. Bester, L.A. Essack, S.Y. 2010. Antibiotic resistance via the food chain: fact or fiction? South African Journal of Science 106(9/10) Art. 281.

Microbiological limits

Mycotoxic Foods

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Aflatoxin B1 chemical structure

Mycotoxins are potentially serious contaminant in foods. These toxins are produced by fungi when storage conditions favour fungal growth, such as in damp grain. Mycotoxins are not easily destroyed by thermal processes that would kill fungi, such as cooking or freezing. As such, prevention of fungal contamination of foods is critical as these toxins can cause illnesses or even death. The most significant mycotoxins include aflatoxins, citrinin, ergot alkaloids, fusarium, ochratoxin, and patin [1]. South African limits for mycotoxin levels in certain foods have been set for Ergot sclerotia, patulin and aflatoxin [2].

Ergot alkaloids are produced by Claviceps species and affect grass species, including cereals. The toxin causes Ergotism which affects the blood supply to the limbs and central nervous system. It is suspected that the Salem witchcraft allegations arose from rye infected with Claviceps resulting in convulsive ergotism. In South Africa grains must contain less than 0.05% Ergot sclerotia by mass.

Patulin is an antiobiotic produced by the soft rot blue mould, Penicillium expansum found on fruit infected. It is toxic to humans and the South African limit for patulin is 50 μg/l in apple juice and other beverages containing apple derivatives.

The risks of mycotoxin contamination are controllable if products are sampled and tested correctly, and health authorities and manufacturers respond appropriately.

Manufacturers must be aware of the legal limits for mycotoxins that must be abided by. As always, manufacturers have the responsibility to ensure their food products are safe.

As a manufacturer, it would be your responsibility to set up specifications covering potential contaminants not only for your finished product, but also raw materials. It is vital to cover all regulations when compiling your specifications, but also to look at, based on industry experience, the chemical, physical and microbial contaminants associated with your product.

Aflatoxin conundrum

Aflatoxins, of which aflatoxin B1 is the most toxic, are more strictly regulated than other mycotoxins. This is due to the risks of chronic, low-level exposure which may result in numerous conditions including immune suppression and even cancer. Studies suggest that increased exposure to aflatoxin increases risk of cancer, especially liver cancer [1]. No ready-to-eat food in South Africa may contain more than 10 μg/kg of aflatoxin (with aflatoxin B1 < 5 μg/kg).

Unfortunately, the fungi that produces aflatoxins grows on maize and peanuts, which are both staple foods. Peanuts are high in protein and due to its high nutritional value is frequently used in nutritional programmes in poorer communities. In 2001 greater than 30 times the legal limit of aflatoxin B1 was found in non-commercial peanut butter used in an Eastern Cape Primary School Nutrition Programme [3]. This potentially increasing cancer risk for millions of school children from 1994.

High levels of aflatoxin can be due to manufacturers’ ignorance, or in some cases the unethical practice of combining contaminated, with uncontaminated product to reduce the level of aflatoxin in the final
product.

Articles by: Gillian de Villiers, co-authored by Norah Hayes

References:
1. Clin. Microbiol. Rev. July 2003 vol. 16 no. 3 497-516 Mycotoxins, J.W. Bennett, and M. Klich
2. Regulations governing tolerance for fungus produced toxins in foodstuffs R.1145 of 2004, October 8.
3. MRC policy brief. August 2001 Aflatoxin in peanut butter (http://scienceinafrica.com/health/aflatoxin-peanut-butter-mrc-policy-brief)

Contaminants

A Weed is just a misplaced plant

bee-549221_1920The Foodstuffs, Cosmetics and disinfectants Act No. 54 of 1972 [1] requires that food marketed to humans is not injurious to health. This is a “catch all” statement – so where no specific regulation exists, in court the onus would be on the producer to ensure the food is safe for human consumption.

Codex defines a contaminant as “Any substance not intentionally added to food or feed for food producing animals, which is present in such food or feed as a result of the production (including operations carried out in crop husbandry, animal husbandry and veterinary medicine), manufacture, processing, preparation, treatment, packing, packaging, transport or holding of such food or feed, or as a result of environmental contamination.” Interestingly they exclude physical contamination such as insect fragments and rodent hair. (CODEX STAN 193-1995)

Currently there are many South African regulations that deal with contaminants including: heavy metals (R500 of 2004), pesticides (R246 of 2005) colourants (R1008 of 1999), hydrocarbons (R230 of 1977) and toxins; even allergens in the labelling regulations (R146 of 2010) could be classed under contaminants.

Rather than expecting a complete absence of a contaminant, regulations often state a permissible level for a specific food group, or all foodstuffs. So it is vital to understand that if a limit exists in a certain product group, this does not mean that other groups are not regulated. Thus, other groups should not contain the contaminant. For example preservatives are permitted in certain food categories, but considered contaminants in similar categories.

This was certainly true for the Pimaricin in export wine case (2009). Pimaricin, commonly used to preserve fruit juices and fruit concentrate was found in some export wines; it was present due to the addition of grape concentrate, occasionally used in the winemaking process. Although allowed in South African wines it is prohibited in some countries.

In some cases regulations do not exist for contaminants, either as the need for regulation has not yet arisen, or because no amount of contamination should be allowed. Two examples that illustrate this point are Sudan red and melamine. When these scares hit in 2005 and 2008 respectively, industry started looking for regulations specifying limits for these compounds.

Sudan red is a colourant used in various industries mainly oil and gas, and should never be in contact with food. As such, there was, and still is, no need for it to be specifically legislated. No amount of Sudan red would be safe for consumption.

For melamine, no legislation existed at the time, but now R1054 of 2009 is in place. Apart from adulteration and food fraud, melamine may also come into contact with food through use of certain containers. Prior to this regulation the onus would have been on the producer to prove that a small amount is firstly safe in the product and secondly present purely due to unavoidable circumstances.

Whether added or unintentional, if it is harmful or not permitted, much like ‘a weed is just a misplaced plant’, these substances if present in foodstuffs are contaminants.

Article by: Norah Hayes

Footnote:
1. Regulations are listed under number and year of first print and should include all subsequent amendments.

Suppliers

My supplier did what?

Many manufacturers are unaware of the extent to which the safety of their end product is dependent on their suppliers. Like the man in the image to the left, each producer in the food chain plays a vital role in holding the chain together to maintain food safety and legality of the end product.

As a food manufacturer you may have asked yourself questions to the tune of “I produce chocolate brownies, why should I worry about pesticides or heavy metals!” – The problem is that our suppliers often aren’t aware of the legal limits of contaminants related to their products. This is often exacerbated when buying raw materials from distributors or importing products, as these legal limits sometimes differ from country to country.

It is important to realise that these limits set by the South African government are not guidelines and that it is a criminal offence to sell product that does not meet the legal limits. Ultimately the onus is on the manufacturer to ensure that their supplier provides them with product that is safe and legally compliant.
So what’s the solution? Firstly, know the legal limits of the products being supplied to you, and secondly if your supplier is supplying product that is legal. To assist producers a set of tools are available to monitor and manage suppliers and include product specifications, certificates of analysis (CoA), supplier assessments, questionnaires, audits and lab tests. To be effective these tools require you as the producer to know what questions to ask your suppliers. Let’s take a brief look.

First, what are the legal limits? We will cover some of the regulations in this issue of Chimera News, but if you have specific questions about the regulations for your product, give us a call.

Ask your suppliers for a specification for each product they supply you with. At minimum these will contain the ingredients, allergens and legal limits for contaminants applicable to the product.

Request a CoA for each batch of product. This is a record showing that the product conforms. If legal limits exist these must appear on the CoA or a laboratory report issued with the CoA.

Supplier assessments, questionnaires and audits assess the supplier’s level of compliance to food safety standards. Ask your supplier what food safety certifications they have, if any, and if they comply to good manufacturing practices (GMP).

Lastly, lab tests can be used to verify conformity, but are expensive and most effective when combined with a risk assessment to determine products that are at greatest risk. Where possible place the responsibility for raw material testing on the supplier.

These are just some of the tools available to help producers manage their end of the supply chain more effectively.

Article by: David James Scott

Contaminants

What are food contaminants?

Agricultural contaminants, environmental contaminants and adulterants, these can be considered as the three main sources of food contaminants. The agricultural contaminants include pesticides and veterinary drugs. Environmental contaminants are those chemicals transferred to food during growing, processing, packaging, storage or distribution; these include heavy metals, mycotoxins, histamine and chemical toxins. Adulterants are substances intentionally added to foodstuffs that are either harmful to the consumer, illegal present or constitute food fraud.