Introduction
The commodity system represented here is similar to those systems frequently found in sub-Saharan Africa, where the small-scale production of groundnuts is practised in combination with the commercial manufacture of peanut butter.
Small scale commercial or peasant farmers' crops are usually short-season, low-input cultivars (cvs) which are intended to be grown within the rainy season, without irrigation. Short season cvs are often more resistant to aflatoxin production than long-season cvs.
Peanut butter is produced from groundnut kernels by roasting, grinding and mixing processes. Emulsifiers are added to ensure that the oil released by grinding remains in suspension. Groundnut processing systems are very complex, involving a variety of manufacturing lines producing differently specified products; a single product line is considered in the current example.
Task 1 - The HACCP team
The HACCP team will include: HACCP specialist, production manager, factory quality assurance manager, mycologist, mycotoxicologist, commodity specialist, socio-economist, agronomist and representatives of trading and export sectors
Tasks 2 and 3 - Product description and intended use
Table 9 shows the product description and intended use.
Tasks 4 and 5 - The Commodity Flow Diagram (CFD), Verified
The CFD was established and verified and is summarised in Figure 11
Table 9. Product Description and Intended Use of End Product
Name of product |
Peanut butter |
Description |
Peanut butter containing emulsifiers and additives to give Type A and Type B products |
Conditions of storage |
Ambient, in consumers' home |
Shelf life |
Type A: 5 months |
Intended use |
Type A: consumed fresh |
Packaging |
Glass jar with sealed lid |
Customer specification |
Type A: Smooth, flowing paste with no off-flavours |
Target consumer |
Whole family, especially infants |
Task 6: Mycotoxin hazard analysis and identification of possible control measures
Hazard Analysis
a) Identification of mycotoxin hazard
Aflatoxin is the only mycotoxin hazard for which the region has regulatory limits for groundnuts and, consequently, it is the only mycotoxin considered. It is also the key mycotoxin associated with groundnuts.
b) Identification of steps in the Commodity Flow Diagram (CFD) where mycotoxin contamination is most likely to occur.
Step 1: On farm, pre-harvest
Pre-harvest contamination with aflatoxin-producing Aspergillus moulds is associated with drought stress and insect damage, both of which are difficult to control without access to irrigation and expensive insecticides. Insect damage provides an entry point for mould propagules, which are often carried by the insect itself. Drought stress can also cause pod splitting in the soil, leaving the kernels exposed to the soil microflora.
Fig. 11. HACCP Flow-diagram: Peanut Butter in Southern Africa
Steps 2: On-farm harvesting
Additional contamination with Aspergillus moulds is unlikely during the harvesting process.
Steps 3 & 4: On-farm, windrow and sun-drying
Contamination by Aspergillus moulds will occur at these steps if a 'safe' moisture level is not achieved within a short period of time.
Step 5: On-farm, removal of pods from haulm
Additional contamination with Aspergillus moulds is unlikely during the removal of the pods from the groundnut haulm.
Steps 6-8: Farm to trader or processor
No aflatoxin contamination should occur here, if the commodity is properly stored and handled.
Step 9: At factory, aflatoxin testing of incoming batches of groundut kernels
There is no risk of additional contamination at this step.
Step 10: At factory, roasting
There is no risk of additional contamination at this step.
Step 11: At factory, hand-sorting
There is no risk of additional contamination at this step.
Steps 12 & 13: At factory, grinding and packing
There is no risk of additional contamination at this step.
c) Possible Mycotoxin Control Measures (Table 10)
If pre-harvest contamination is to be avoided, the most effective control measures will involve those procedures associated with GAP, which prevent mould contamination. Such control measures will include the prevention of drought stress and insect damage, the use of fungal-resistant varieties (if available), the use of fertilisers and the control of weeds. The use of biological control agents such as atoxigenic strains of Aspergillus flavus has been piloted in the USA and Australia, but has not, as yet, been widely adopted as a fully acceptable practice.
Immediately after harvest, it is essential that the groundnuts are dried to a 'safe' moisture level (aw £ 0.82) as rapidly as possible. Artificial drying procedures are not generally available in southern Africa, where sun-drying is normally performed on the haulm, by a combination of windrow drying followed by drying on a flat surface.
A further control measure is the segregation of contaminated nuts during harvesting, drying and handpicking. The ultimate segregation procedure is the inspection of individual batches of groundnuts, by sampling and aflatoxin analysis, and the rejection of excessively contaminated batches.
Tasks 7-10 - Development of a HACCP Plan
A worksheet summarising the HACCP Plan for peanut butter is given in Table 10
Step 1: On farm, pre-harvest - GAP
GAP will prevent pre-harvest mould contamination, although the effects of inclement weather (drought stress, prolonged rains) can be extremely difficult, if not impossible, to control.
Steps 2: On-farm harvesting - GAP
Again, GAP will prevent pre-harvest mould contamination. The selection of the appropriate harvesting time is important so that the groundnuts are harvested immediately they reach maturity. It is also important that the pods are not damaged during harvesting, in order to maintain a protective environment for the groundnut kernels.
Steps 3 & 4: On-farm, windrow and sun-drying - CCP1 and CCP2
These steps are both CCPs, since mould and aflatoxin contamination will rapidly occur if the groundnuts are not dried to a safe moisture level (aw £ 0.82) as rapidly as possible. The precise combination of moisture level and maximum permitted drying period will vary with groundnut variety and agroclimatic zone, and will need to be determined using local knowledge. It is envisaged that the preliminary windrow drying should achieve a moisture level of £ 12%, whereas the second drying phase, on a flat surface, should attain a £ 7% moisture level. However, mould and aflatoxin contamination can still occur if the safe moisture levels are not attained sufficiently rapidly.
Step 5: On-farm, sorting during removal of pods from haulm - CCP3
The control measure is the rejection of pods which are discoloured, mouldy and/or damaged whilst the pods are being removed from the haulm. The critical limit will be determined by the maximum percentage of unacceptable pods which, typically, can be removed during the harvesting process. For the purposes of this example it is assumed that 95 per cent of unacceptable pods could reasonably be expected to be removed during harvesting.
Steps 6-8: Farm to trader or processor - GAP
The careful storage and handling of both the pods and the kernels is classified as GAP and GMP. However, it is essential that the groundnuts are maintained in a clean, dry and undamaged state during these steps, if contamination is to be avoided.
Step 9: At factory, aflatoxin testing of incoming batches of groundut kernels
Step 9 is a CCP which segregates those batches of groundnuts which contain an unacceptable level of aflatoxin B1. The aflatoxin content of every batch of groundnut kernels is determined by selecting a representative sample of 20kg, at least, and analysing for aflatoxin using a simple, semi-quantitative test kit. (More sophisticated analytical methods such as high performance liquid chromatography, HPLC, may be used, of course, if available.) The critical limit will be an acceptable level of aflatoxin B1 which, after the implementation of steps 10 and 11, will allow the target level of 20 mmg/kg aflatoxin B1 to be attained. In this example, the HACCP team considered that the critical limit should be 30 mmg/kg aflatoxin B1.
In a situation where it is felt that pre-harvest contamination is under control, or is not a significant problem, Step 9 may eventually be utilised as a component of the verification procedure.
Step 10: At factory, roasting - GMP
The roasting of the groundnut kernels under appropriate conditions is considered as GMP. However, the roasting process can cause a 20-30% reduction in aflatoxin contamination, depending upon the operating conditions utilised.
Step 11: At factory, hand-sorting - GMP
The primary aim of the hand-sorting process is the removal of burnt kernels, which will have a detrimental effect on the quality of the peanut butter. However, Step 11 also provides a final opportunity to remove obviously shrivelled and/or damaged kernels before the grinding process; and, potentially, to simultaneously reduce the level of aflatoxin in the final product. The HACCP team was uncertain whether hand-sorting after roasting would have a significant effect on the aflatoxin level and, consequently, did not define step 11 as a CCP. However, this step would become a CCP if subsequent studies clearly demonstrated the efficacy of the hand-sorting process as a means of removing aflatoxin.
Steps 12 & 13: At factory, grinding and packing - GMP
The quality of the grinding and packing procedures is controlled by GMP. The grinding procedure, used in the conversion of kernels to peanut butter, will effect the distribution of aflatoxin in the end-product, but will not change the overall level of contamination.
Stage 11: Establish verification procedures
Verification procedures will be established for each of the CCPs, and the HACCP plan will be regularly audited, and amended as necessary
Stage 12: Establish documentation and record keeping
The HACCP plan will be fully documented, and appropriate records kept at each CCP.
Table 10. HACCP Plan Worksheet: Peanut butter produced in southern Africa
Process Step |
Description of hazard |
Possible Control Measures |
Control |
Critical Limits |
Monitoring Procedures |
Corrective Actions |
Records |
1 |
MOULD CONTAMINATION |
Control drought stress and insect damage |
GAP |
|
|
|
|
2 |
MOULD CONTAMINATION |
Harvest when nuts mature Remove & burn diseased plants Protect haulms from rain Avoid damage to pods |
GAP |
|
|
|
|
3 |
MOULD CONTAMINATION |
Dry to safe moisture level (e.g £12%) |
CCP1 |
Safe moisture level & maximum drying period to be determined locally |
Timing of drying period |
Remove mouldy nuts |
Farmers records |
4 |
MOULD CONTAMINATION |
Dry to safe moisture level (e.g £7%) |
CCP2 |
Safe moisture level & maximum drying period to be determined locally |
By observing physical characteristic of nut eg crackling noise when pod is shaken |
Remove mouldy nuts |
Farmers records |
5 |
MOULD CONTAMINATION |
Avoid damage to pods Discard unacceptable pods |
CCP3 |
£ 5% |
Visual inspection of pods during removal from haulm |
Resort pods and remove remaining unacceptable pods |
Framers recors |
6 |
MOULD CONTAMINATION |
Keep pods clean & dry |
GAP |
|
|
|
|
7 |
MOULD CONTAMINATION |
Keep pods clean & dry |
GAP |
|
|
|
|
8 |
MOULD CONTAMINATION |
Keep pods & kernels clean & dry |
GAP |
|
|
|
|
9 |
AFLATOXIN CONTAMINATION |
Collect 20kg representative sample from incoming batches and analyse for aflatoxin |
CCP4 |
Aflatoxin B1 £ 30 mmg/kg |
Aflatoxin testing using rapid kits |
Reject batches not meeting aflatoxin specification |
Factory records |
10 |
AFLATOXIN CONTAMINATION |
Roast at appropriate temp. |
GMP |
|
|
|
|
11 |
AFLATOXIN CONTAMINATION |
Remove shrivelled & burnt kernels by hand picking |
GMP |
|
|
|
|
12 |
AFLATOXIN CONTAMINATION |
Ensure cleanliness of equipment |
GMP |
|
|
|
|
13 |
AFLATOXIN CONTAMINATION |
Use clean, airtight packing |
GMP |
|
|
|
|