By Ruth Vaughan
Food safety is a rapidly emerging discipline. We are what we eat. How safe is our food?
What is food safety?
Food safety is a scientific discipline describing handling, preparation, testing and storage of food in ways that prevent food-borne illness.
What are the food safety hazards?
- Disease causing agents (bacterial, fungal, viral)
- Pesticide Residues
- Heavy metals
- Foreign bodies (plastic, metal filings, sticky plasters, finger nails, hair, jewelry, etc.)
- Poisonous substances (mycotoxins and other toxins)
- High nitrates / nitrites
What are the Standards
In 1963, the World Health Organization (WHO) and the The Food & Agriculture Organization (FAO) published the CODEX ALIMENTARIUS which serves as a guideline to food safety.
Every country has its own standards on food safety requirements adapted from the Codex Standards.
Many large buyers and supermarket chains have taken these standards and adapted them to create a point of difference for their market.
What are the Standards for Kenya?
The Kenya Bureau of Standards(KEBS) is the Lead Agency for food safety standards in Kenya.
The KEBS Standards are going through a rapid period of updating and development through a process of PPP collaboration.
All standards require analysis certificates of produce from approved laboratories.
What are the Standards for Export Produce?
Export produce should be tested and comply with the Standards for the destination country AND the Standards for the destination market
In addition to Food Safety Testing of final product, the production process is generally monitored throughout the growing season and should comply with various Labels or Audits required by the destination market, for example Global Gap & Fairtrade.
Food Safety Testing Laboratory Requirements
A good laboratory should have a proper quality management system in place, be ISO 17025 accredited, and recognized by the appropriate local government bodies, for e.g. NEMA and KEBS.
Proper sampling procedures, sample handling, shipping and logistics are of the utmost importance for food safety testing as pesticide residue decay can occur over time, and pathogen loads & mycotoxins levels can increase.
A quick result turn-around is crucial for food safety testing. Some produce is held in storage until the results are confirmed.
It goes without saying that accurate, scientifically based and reproducible results are a must. And, of course, client confidence and client confidentiality are most important.
Very expensive, state of the art machines are needed, especially for pesticide residue analysis and heavy metal analysis, as the required Limits of Detection(LOD’s) are extremely low.
This is the analysis of disease causing agents, bacteria, fungi, viruses and helminths. It is more critical for food that is eaten fresh. Proper cooking generally kills most pathogens. Death and disease from E coli outbreaks from eating salads is a regular occurrence around the world.
“The German E. coli O104:H4 was a pathogen of a high virulence that suddenly emerged, and that might point to an unnatural phenomenon. The 2011 outbreak centered on Northern Germany was large, severe, and deadly. Out of the 2,987 confirmed cases not involving hemolytic uremic syndrome (HUS), 18 died. And out of 855 HUS cases, 35 died.”
Pathogen analysis should be done throughout the year on produce, irrigation water, soil, compost, pack house surfaces etc. Farm should have a robust HACCP system in place to mitigate any risk of pathogen contamination. Very wet weather and the floods that we are seeing at the moment greatly increase the risk of pathogens in our foods, and indeed floods are responsible for many E coli outbreaks.
Pesticide Residue Analysis
Pesticide residue analysis is via GC LC/MS MS, requiring very expensive and sensitive equipment and handling, with very low limits of detection. Maximum residue limits for produce are country and market-specific. Most markets look at not just the amount of one pesticide, but the number of pesticides in a product, as a combination of different pesticides can be worse.
Pesticides in produce can be controlled through proper on-label use of pesticides, adhering strictly to the rate of spraying and the post harvest interval. Residue decay is not an exact process and it is important to back up pesticide use with Maximum Residue Level (MRL) Analysis.
The presence of high pesticide residues, or too many residues, limits, not just a specific producer’s market access, but can affect the whole country, as we found out in French beans a few years ago, causing major economic damage to the region.
Heavy Metal Analysis
The main threats to human health from heavy metals are associated with exposure to lead, cadmium, mercury and arsenic. These metals have been extensively studied and their effects on human health regularly reviewed by international bodies such as the WHO.
Heavy metals can be naturally in the soil, water or air, or can be introduced via other farm inputs (fertilizers, pesticides and pollution). In order to limit the risk of heavy metal contamination of your produce it is good to analyze soil, water, compost and farm inputs. Dump sites, and municipal waste can have very high levels of heavy metals. Lead can be a major risk in soils and waters near busy roads (this is now reducing with lead-free fuels). High arsenic levels can be found in some underground waters, especially near geothermally active areas.
Laboratories can analyze for iron fillings and other metals that may come from the processing equipment, but it is up to the farms to put proper Hazard Analysis And Critical Control Point (HACCP) Systems in place to reduce the risk of foreign body contamination.
Mycotoxins are toxic secondary metabolic products of molds. Mycotoxins are invisible, tasteless, chemically stable and resistant to temperature and storage.
Mycotoxin producing fungi can be divided into two groups.
- Field fungi (such as Fusarium sp.) typically produce mycotoxins in the field (“pre-harvest”)
- Storage fungi (such as Aspergillus and Penicillium sp.) typically occur after harvest (“post-harvest”)
Mycotoxin infection occur at all levels of food and feed production, including crop and animal production, processing and distribution. According to the FAO (Food and Agriculture Organization) around 50% of the world’s crop harvests may be contaminated with mycotoxins. Mycotoxin outbreaks are common in Africa, cause many deaths and are linked to agricultural practices and climatic conditions.
GMO’s are currently banned in Kenya – so the risk of GMO’s is very slight. Certain DNA sequences used in genetic modification can be picked up by ELISA testing. Research is on going on the effect of GMO’s on human health. GMO’s can also affect the environment and are banned by some markets. Observation on how GMO’s can directly affect human health can be, increased food allergies, antibiotic resistance, lower nutrient density in food, increased plant toxin production in food.
Fresh Produce Africa (FPA) 2018, an International Trade Expo for the African Fruits and Vegetables Market is running concurrently with the International Floriculture Trade Expo (IFTEX) at the Oshwal Centre, 6-8th June 2018.
Come and visit our CropNuts/Groen Agro Stand at FPA to learn more about Food Safety and how we can help you comply, or email us at [email protected].
Ruth Vaughan is the Technical Director at Crop Nutrition Laboratory Services Ltd. (CROPNUTS). Ruth is also a contributing author to Kenya’s leading horticulture magazines such as the HortFresh Journal, HortiNews and Floriculture. Ruth is a great believer in soil health, organic matter, biochar and carbon sequestration as a way to alleviate climate change and increase food security. Loves visiting farmers and seeing all the different farming methods