Safety of a street vended traditional maize beverage, ice-kenkey, in Ghana

Food Control 55 (2015) 200e205

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Safety of a street vended traditional maize beverage, ice-kenkey, in Ghana Amy Atter, Hayford Ofori, George Anabila Anyebuno, Michael Amoo-Gyasi, Wisdom Kofi Amoa-Awua* Food Research Institute, Council for Scientific and Industrial Research, Post Office Box M.20, Accra, Ghana

a r t i c l e i n f o

a b s t r a c t

Article history: Received 8 November 2014 Received in revised form 14 February 2015 Accepted 24 February 2015 Available online 5 March 2015

Ice-kenkey is a chilled cereal beverage sold as street food in some open markets in Ghana. It is produced by mashing and sweetening kenkey, a stiff dumpling produced from fermented maize meal. The safety of street vended ice-kenkey was assessed by microbiological, elemental and myco-toxicological analysis of ice-kenkey and intermediary products obtained from 16 producers in four open markets in the Accra and Tema metropolis. A tenfold increase in counts of aerobic mesophiles, and yeast and moulds were recorded during the production of ice-kenkey. Coliform bacteria, E. coli and Staphylococcus aureus which were not detected in the starting materials were found partway through production or in the final product. The mean microbial counts in the packaged ice-kenkey were 106e107 CFU/g for aerobic mesophiles, 104e105 CFU/g for yeast and moulds, 10e1000 CFU/g for total coliforms and 10e100 CFU/g for S. aureus. E. coli counts of 10 CFU/g were recorded in samples from three out of the four markets. The microbial load could be eliminated by pasteurizing ice-kenkey at 80
C for 15 min. The mean concentration in mg/kg of Fe was between 15.97 and 29.48, Cu, 0.57 to 1.41, Mn, 0 to 2.55, Pb 0 to 1.25 and Zn 0.47 to 6.17. Total aflatoxins content in samples ranged from 7.04 to 22.17 mg/kg and included a range of 7.01e20.54 for aflatoxin B1, 0.51 to 1.63 for aflatoxin B2 and 0e0.47 mg/kg for aflatoxin GI. Aflatoxin G2 was not detected in any of the samples. A simplified training module based GMP, GHP and a HACCP plan was developed and used to train ice-kenkey producers in Accra in collaboration with municipal authorities. © 2015 Elsevier Ltd. All rights reserved.

Keywords: Ice-kenkey Kenkey Street food Indigenous fermented food

1. Introduction The street food industry plays a vital role in meeting food requirements of commuters and urban dwellers in many cities and towns in developing countries. It feeds millions of people daily with a wide variety of ready-to-eat foods and beverages that are relatively cheap and easily accessible (Barro et al. 2007; FAO 1989, Mensah, Owusu-Darko, & Ablorde, 2002). According to Mensah et al. (2002) consumption of street food is common in many countries where unemployment is high, salaries are low, work opportunities and social programmes are limited and where urbanization is taking place. Street food vendors benefit from a positive cash flow, often evade taxation and can determine their own working hours. They provide an essential service to people on low incomes and such consumers are often more interested in its

* Corresponding author. Tel.: þ233 302 519092. E-mail address: [email protected] (W.K. Amoa-Awua). http://dx.doi.org/10.1016/j.foodcont.2015.02.043 0956-7135/© 2015 Elsevier Ltd. All rights reserved.

convenience than in questions of its safety, quality and hygiene (Mensah et al., 2002). Several authors have commented that streetvended foods raise concerns with respect to their potential for serious food poisoning outbreaks due to improper food handling practises. The hygienic aspects of vending operations are therefore a major source of concern for food control officers (Rane, 2011). In Ghana one of the most common street foods is kenkey, a sour stiff dumpling prepared from fermented maize meal. Kenkey is produced by steeping whole or dehulled maize grains in water for about 2 d. The steeped grains are milled and kneaded into a dough with a moisture content of about 55%. The dough is allowed to ferment spontaneously for about 2e4 d. Part of the sour dough is then cooked into aflata and this is mixed with the remaining uncooked dough to attain a characteristic sticky texture. The mixture is moulded into balls, wrapped in leaves and cooked for at least 3 h into kenkey (Halm, Amoa-Awua, & Jakobsen, 2004). Two main types of kenkey are known, both produced from whole maize grains, Ga-kenkey and Fanti-kenkey. Fanti-kenkey is fermented for at

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least 3 days whilst Ga-kenkey is fermented for at least 2 days. Gakenkey contains salt whilst Fanti-kenkey does not. Whilst Ga-kenkey is wrapped and cooked in maize husks, Fanti-kenkey which is cooked for a longer period is wrapped in plantain or banana leaves (Halm et al., 2004). Kenkey is consumed with fried or grilled fish and a vegetable sauce as a main meal. Kenkey may also be consumed as a chilled beverage, ice-kenkey, after it is mashed with water and sugar and milk added. Ice-kenkey is commonly produced by breaking or crumbling Ga or Fanti kenkey into pieces and milling it in service mills at the open markets into a mash. The mash is then blended with water, sugar and powdered milk into a beverage. In place of milk some producers rather mill the kenkey pieces together with roasted groundnuts. The beverage is either packaged in low density polyethylene bags or in screw capped bottles and packed in an ice chest containing crushed ice and sold as ice-kenkey. Despite the very low pH of the cereal beverage, about 3.7, its safety is of concern due to some poor manufacturing and hygienic practises observed during the semi-commercial operations. The production areas, utensils and the milling machines are often not adequately cleaned. Most of the producers do not adhere to the basic elements of good hygienic practises. This work was carried out to assess the safety of ice-kenkey sold in four open markets in Accra with respect to their microbiological, heavy metal and aflatoxin contamination in order to develop an HACCP model for preventive control which could be used to train ice-kenkey producers. 2. Materials and methods 2.1. Sampling Balls of kenkey broken into pieces by hand, milled kenkey, constituted ice-kenkey containing sugar and powdered milk and ice-kenkey packaged in polyethylene bags or screw capped bottles were collected from producers from the Madina, Ashaiman, Mallam-Atta and Agbogbloshie markets in the Accra and Tema metropolis. For each market, samples were collected from four producers. The samples were transported in an ice chest immediately to the laboratory for analysis. 2.2. Microbiological analysis For all samples, 10 g were homogenized in 90 ml sterile diluent (0.1% peptone, 0.8% NaCl, pH 7.2) in a stomacher (Lab Blender, Model 4001, Seward Medical, London, England) for 30 s at normal speed. From appropriate ten-fold dilutions, aerobic mesophiles were enumerated by pour plate on Plate Count Agar (Oxoid CM325; Oxoid Ltd., Basingstoke, Hampshire, UK), incubated at 30
C for 72 h according to NMKL No. 86 (2006). Yeast and moulds were enumerated by spread plate on Dichloran-Rose Bengal Chloramphenicol Agar (Oxoid CM0727), pH 5.6, containing Chloramphenicol supplement to inhibit bacteria growth and incubated at 25
C for 48e120 h in accordance with ISO 21527-1:2008. Total coliforms and E. coli were enumerated by pour plate on Trypton Soy Agar (Oxoid CM131), pH 7.3 overlaid with Violet Red Bile Agar (Oxoid CM107), pH 7.4 and incubated at 37
C for 24 h for total coliforms and at 44
C for 24 h for E. coli. Colonies suspected to be coliforms were confirmed on Brilliant Green Bile Broth (Oxoid CM31), pH 7.4, incubated at 37
C for 24 h according to NMKL No. 44 (2004) and E. coli on EC Broth (Oxoid CM853), pH 6.9, followed by Trypton Water (Oxoid CM87), pH 7.5, all incubated at 44
C for 24 h according to NMKL. No. 125 (2005). Staphylococcus aureus was determined by spread plate on BairdeParker Agar (BP, CM 275 Oxoid Ltd, Hampshire, England) with Egg Yolk Tellurite Emulsion (SR54) added and Blood Agar Base (BAB, CM 55 Oxoid Ltd,

201

Hampshire, England). Both media were incubated at 37
C for 48 h. S. aureus counts were confirmed by biochemical tests according to NMKL Method No. 66 (2009). 2.3. Chemical analysis 2.3.1. Determination of pH Ten grams of sample was blended with 10 ml of distilled water and the pH determined using a pH meter (Radiometer PHM 92, Bagsvaerd, Denmark). The pH meter was calibrated using standard buffers. 2.3.2. Determination of trace metal concentrations by atomic absorption spectrophotometry The dry ash method was used in the present study (AOAC, 2005). Kenkey samples were homogenized using a laboratory stainless steel mixer. Three grams of sample was weighed into cleaned dried porcelain crucible and placed in the Muffle furnace at a temperature 550
C for 8 h. The crucible with ash was put in desiccator to cool. Five ml of nitric acid of mass fraction not less than 65%, having a density of approximately r (HNO3) ¼ 1400 mg/ml was added and heated until the ash dissolved. Ten ml of 0.1 mol/l nitric acid was added and filtered into a 50 ml volumetric flask. The resultant solution was topped up to the mark with 0.1 mol/l nitric acid. A blank solution was treated the same way as the sample. The absorbance values were read at the appropriate wavelengths for the required metals in a Buck Scientific 210VGP Flame Atomic Absorption Spectrophotometer (Buck Scientific, Inc. East Norwalk, USA). The cathode lamps used were copper (Cu) wavelength 324.8 nm, lamp current 1.5 mA; iron (Fe), wavelength 248.3 nm, lamp current 7.0 mA; manganese (Mn) wavelength 279.5 nm, lamp current 3.0 mA; lead (Pb), wavelength 217.0 nm, lamp current 3.0 mA; and zinc (Zn) wavelength 213.9 nm, lamp current 2.0 mA. Air/acetylene gas was used for all analysis. The metal content of the samples were derived from calibration curves made up of a minimum of three standards. 2.3.3. Extraction and HPLC analysis for aflatoxin concentrations The extraction procedure used for the determination of aflatoxins was by Stroka and Anklam (1991). A test portion (50 g) was extracted with a 200 ml methanol/water solvent solution containing 5 g of sodium chloride. The sample extract was filtered, diluted with phosphate buffered saline to a specified solvent concentration, and applied to the immunoaffinity column (R-Biopharm Rhone Ltd. Easi-Extract Aflatoxin) containing antibodies specific for aflatoxins B1, B2, G1, and G2. Aflatoxins were eluted from the immunoaffinity columns with neat methanol. Aflatoxins were quantified by reverse-phase high performance liquid chromatography with post column derivatisation involving bromination. The post column derivatisation was achieved with pyrimidinum hydrobromide perbromide followed by fluorescence detection. The instrument system used for the HPLC analyses was from Waters Associates (Milford, MA, USA) and included Waters 1525 Binary HPLC pump, Waters 2707 Autosampler, Waters Model 1500 Column Heater, Waters 2475 Multi l Fluorescence Detector and Breeze 2 software. Separation of the aflatoxins was carried out on a Spherisorb S5 ODS-1 column of dimensions 25  4.6 mm packed with 5 mm particles (Phase separations Inc., Norwalk, USA) maintained at 35
C. The HPLC mobile phase flow rate was 1.0 ml/min and post column bromine derivatization of Aflatoxin B1 and G1 was achieved by PBPB dissolved in 500 ml of distilled water pumped at a flow rate of 0.5 ml/min using Eldex precision metering pump (Eldex Laboratories Inc., San Carlos, USA). The excitation and emission wavelengths used were 360 nm and 440 nm respectively. The aflatoxins

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were identified by their retention times, and peak areas were used to determine their concentrations in the samples by reference to standard curves obtained by chromatographing pure aflatoxin standard (obtained from R-Biopharm) solutions under identical conditions. 3. Results and discussion 3.1. The pH of ice-kenkey All the ice-kenkey producers in the four open markets covered in this work used only Fanti-kenkey to produce ice-kenkey. The pH of 64 samples of ice-kenkey and intermediary products analysed were in the range of 3.68e3.79 for the kenkey pieces, 3.75 to 3.83 for milled or mashed kenkey, 3.58 to 3.70 for constituted ice-kenkey and 3.57 to 3.68 for the packaged ice-kenkey (either in polyethylene bags or screw capped bottles). The low pH values recorded for the ice-kenkey and intermediary products were consistent with the low pH values of 3.6e3.9 reported for kenkey by several workers (Halm, Lillie, Sorensen, & Jakobsen, 1993; Halm, Osei-Yaw, Hayford, Kpodo, & Amoa-Awua, 1996). The low pH of kenkey contributes substantially to the safety of the product and is the result lactic acid fermentation which occurs during steeping of maize grains and dough fermentation in kenkey production (Amoa-Awua, Halm, & Jakobsen, 1998; Olsen, Halm, & Jakobsen, 1995). Lactobacillus fermentum has been identified as the dominant lactic acid bacteria responsible for the fermentation of kenkey (Halm et al. 1993; Hayford, Petersen, Vogensen & Jakobsen 1999). 3.2. Microbial population in ice-kenkey The results of the microbiological analysis of the broken up pieces of kenkey, the milled or mashed kenkey, the constituted icekenkey containing sugar and powdered milk, and the packaged icekenkey in polyethylene bags or bottles are shown in Table 1. Some of

the products contained roasted groundnuts which were added and milled together with the kenkey pieces. In sampling and analysis such products were not distinguished from products which contained milk. The result for each market in the table represents the mean value for four samples obtained from four different producers from each of the four markets. The microbial population of the kenkey pieces, was composed of aerobic mesophiles and yeast and moulds in all 16 samples examined. Neither coliform bacteria, E. coli nor Staph aureus were present in any of these samples. Fanti-kenkey is boiled for 6 h and Ga-kenkey for 3 h, therefore, kenkey is reportedly sterile after production (Atopla, 2006; Halm et al. 2004). The microbial counts found on the kenkey pieces could have resulted from contamination from the hands of the producers during the breaking up of the balls of kenkey into pieces. It may also have been the result of using kenkey which was not freshly produced. Atopla (2006) monitored microbial counts in kenkey during storage and recorded no or extremely low aerobic mesophilic and yeast and moulds counts in samples purchased on the same day of production. After four days of storage at ambient temperature, Atople (2006) recorded aerobic mesophilic and yeast and mould counts which were of the magnitude recorded in the present work for the kenkey pieces i.e. in the range of 103e106 and 103e105 CFU/g respectively. Since no counts were obtained for S. aureus and total coliforms it is likely that contamination of the kenkey pieces from the hands of the producers would have been minimal. Table 1 shows that during the entire ice-kenkey production there was an increase in the population of aerobic mesophiles by one log unit in samples from three markets, 106e107 CFU/g, but by three log units in samples from the fourth market i.e. Agbogloshie market, 103e106 CFU/g. The increase in mean aerobic mesophilic counts occurred at different processing stages at different production sites. There was generally also a one log unit increase in the population of yeast and moulds during the ice-kenkey production, but this occurred mainly during milling of kenkey. Contamination of ice-

Table 1 Microbial population in CFU/g at various stages of ice-kenkey production in four open markets. Sample

Madina market

Aerobic mesophiles Kenkey pieces Milled kenkey Constituted ice-kenkey Packaged ice-kenkey

Ashaiman market

(1.5 (3.3 (4.3 (4.8

± ± ± ±

2.6)106 3.2)106 2.6)106 2.9)107

(1.1 (1.2 (2.3 (4.0

± ± ± ±

1.7)106 2.1)107 4.1)107 3.3)107

(2.2 (4.4 (2.0 (7.1

± ± ± ±

3.9)106 2.9)106 3.5)107 4.6)107

(6.6 (1.9 (1.2 (2.2

± ± ± ±

4.7)103 1.3)105 3.9)106 1.0)106

Yeast and moulds Kenkey pieces Milled kenkey Constituted ice-kenkey Packaged ice-kenkey

(3.6 (1.9 (1.9 (8.3

± ± ± ±

3.7)103 2.8)104 2.6)105 1.5)105

(7.9 (2.2 (1.9 (3.0

± ± ± ±

1.2)104 3.9)105 3.4)105 1.7)105

(1.6 (6.2 (7.5 (1.4

± ± ± ±

2.9)105 2.3)104 1.3)104 2.5)105

(2.8 (2.9 (2.2 (1.1

± ± ± ±

1.7)103 2.0)104 2.2)104 1.4)104

Coliforms Kenkey pieces Milled kenkey Constituted ice-kenkey Packaged ice-kenkey

nd nd nd (2.8 ± 1.5)10

nd (1.0 ± 1.9)102 (7.2 ± 3.1)102 (7.5 ± 1.1)102

nd nd (3.0 ± 2.0)10 (6.5 ± 3.5)102

nd (2.2 ± 4.5)102 (2.9 ± 4.7)102 (1.7 ± 2.1)103

Esherichia. coli Kenkey pieces Milled kenkey Constituted ice-kenkey Packaged ice-kenkey

nd nd nd nd

nd nd nd (4.0 ± 2.0)10

nd nd nd (2.5 ± 2.3)10

nd nd (2.4 ± 2.8)10 (9.1 ± 3.1)10

Staphylococcus aureus Kenkey pieces Milled kenkey Constituted ice-kenkey Packaged ice-kenkey

nd nd nd (6.8 ± 1.3)10

nd nd nd (9.7 ± 1.1)10

nd nd nd (3.0 ± 2.0)10

nd nd nd (1.4 ± 1.0)102

Each value represents the mean and standard deviation of samples from four producers in the market. nd e not detected.

Mallam-Atta market

Agbogbloshie market

A. Atter et al. / Food Control 55 (2015) 200e205

kenkey with coliforms, E. coli or Staph aureaus occurred mainly during the constituting or blending of the mashed kenkey with water, sugar and milk powder or during packaging which were both carried out as manual operations. The heaviest microbial loads were found in the final packaged products rather than at the preceding production stages. This was not surprising because no preservation measures were applied during processing which would have reduced microbial load. Icekenkey is prepared and sold as a chilled ready-to-drink beverage and producers expect that it will be consumed at the time of purchase or refrigerated if it is to be kept overnight. It is therefore not pasteurized or given any preservation treatment to extend its shelf life by the producers. The population of aerobic mesophiles in the ready-for-sale packaged products were in the range of 106e107 CFU/g, yeast and moulds 104e105 CFU/g, total coliforms 10e1000 CFU/g, E. coli 0e90 CFU/g and S. aureus 30e140 CFU/g. The Ghana Standards for fermented maize products are 100 CFU/g for S. aureus and 10 CFU/g for E. coli (Ghana Standards Authority, 2013). Most of the ice-kenkey samples assessed in the present work, therefore, did not meet the Ghana standards due to the level of E. coli. The standards are usually enforced within the formal food sector whilst street food vending is considered as an informal activity. Feglo and Sakyi (2012) also isolated E. coli and S. aureus as well as Aeromonas hydrophila from street vended ice-kenkey samples in Kumasi another city in Ghana. A test conducted by the present authors in which ice-kenkey was pasteurized at 80
C for 15 min after bottling showed no counts for various types of microorganisms assessed. The microbial load in the ice-kenkey before bottling was aerobic mesophiles, 3.2  105 CFU/g; yeast and moulds, 4.1  104 CFU/g; total coliforms, 190 CFU/g; E. coli, 40 CFU/g and no count for S. aureus. None of these microorganisms was detected in the pasteurized ice-kenkey.

203

Table 3 Aflatoxin content of ice-kenkey samples in mg/kg wet weight obtained from producers in four open markets. Markets

Aflatoxin B1 Aflatoxin B2 Aflatoxin G1 Aflatoxin G2 Total (mg/kg)

Madina 15.79 ± 0.66 1.25 Ashaiman 7.01 ± 0.28 0.51 Mallam-Atta 10.80 ± 0.42 0.73 Agbogbloshie 20.54 ± 0.93 1.63

± ± ± ±

0.35 0.13 0.09 0.53

nd 0.47 ± 0.06 0.46 ± 0.09 nd

nd nd nd nd

17.04 7.99 11.99 22.17

Each value represents mean and standard deviation for three samples of ice kenkey obtained from the market. nd e not detected.

Of the five trace metals, it was Fe which was present in very excessive amounts. Whereas the concentration of Cu and Mn, and to some extent Pb, reduced as the product was diluted during production, the concentration of Fe increased drastically in most samples during milling and reduced only slightly after this. The concentration of Fe increased from between 6.44e39.41 to 33.70e75.39 mg/kg during milling but reduced to 15.97e29.48 mg/ kg in the Constituted ice-Kenkey. This final Fe concentration was far in excess of the maximum recommended iron level of 0.3 mg/kg by WHO (WHO, 1985). Excessive intake of iron is associated with an increase risk in colorectal cancer (Senesse, Meance, Cottet, Faivre & Boutron-Ruault., 2004) though iron deficiency anemia affects one third of the world's population. The increase in Fe concentration during milling could be attributed to release of iron from certain parts of the locally fabricated milling machine into the food. Some fabricators use galvanized iron rather than stainless steel to manufacture the mills. The acidic nature of the kenkey would promote rusting of the machine surfaces in contact with the product leading to release of iron into the food. The presence of Cu was detected in all the samples analysed and reduce slightly in concentration throughout production. The concentration of Cu in the final products were between 0.57 and 1.41 mg/kg, all within the WHO recommended limit of 3.0 mg/kg. Cu is an essential constituent of some metallo enzymes and is required in haemoglobin synthesis and in the catalysis of metabolic growth (Silvestre, Lagarda, Farra, Martineze-Costa, & Brines, 2000). There were no significant differences in concentration of Cu in icekenkey produced in the different markets. The concentration of Mn also reduced during the production of ice-kenkey due to dilution of the product along the processing line. In the kenkey pieces the concentration of Mn in the samples from the four markets were between 2.17 and 4.83 mg/kg, whilst in the

3.3. The presence of heavy metals in ice-kenkey The concentration of five trace metals in ice-kenkey at various stages of production are given in Table 2. Analysis of the broken kenkey pieces revealed the order Fe > Mn > Cu > Zn > Pb, Fe > Zn > Mn > Pb > Cu, Fe > Mn > Zn > Cu > Pb, Fe > Mn > Zn > Cu > Pb for Ashaiman, Madina, Mallam-Atta and Agbogbloshie markets respectively. Iron, copper, manganese and zinc are classified as nutritionally essential metals, but become toxic when accumulated excessively in the body tissues, and are not metabolized (Dobaradaren et al., 2010).

Table 2 Concentration of different heavy metals (mg/kg) in products at various stages of ice-kenkey production in four open markets. Sample

Market

Cu

Kenkey pieces

Ashaiman Madina Mallam-Atta Agbogbloshie

2.06 3.74 1.97 1.46

± ± ± ±

0.33a 0.25b 0.18a 0.16a

Fe 39.41 22.60 6.44 8.27

± ± ± ±

3.06d 3.41c 1.41c 0.26e

Mn 2.19 4.83 2.17 3.50

± ± ± ±

0.02f 0.54g 0.11f 0.61h

Pb ndi 1.43 ± 1.89j ndi ndi

Zn 0.45 19.42 2.03 3.21

± ± ± ±

0.10k 2.73l 0.09k 0.31k

Milled kenkey

Ashaiman Madina Mallam-Atta Agbogbloshie

0.90 1.25 1.57 1.10

± ± ± ±

0.06a 0.24ab 0.09b 0.00a

33.70 29.12 35.48 75.39

± ± ± ±

7.04c 0.54c 0.64c 1.98d

3.38 2.14 1.71 1.87

± ± ± ±

0.23f 0.24e 0.01e 0.28e

ndg 1.94 ± 0.06h ndg 0.57 ± 0.00g

0.27 13.4 6 3.66 5.76

± ± ± ±

0.04j 0.06k 0.38l 1.27m

Constituted ice-kenkey

Ashaiman Madina Mallam-Atta Agbogbloshie

0.73 1.41 1.19 0.57

± ± ± ±

0.03a 0.11a 0.11a 0.72a

23.28 21.44 15.97 29.48

± ± ± ±

0.25b 2.28b 1.61c 1.34d

2.55 ± 0.47e 1.06 ± 0.38f ndj 1.84 ± 0.04ef

ndh 1.25 ± 0.06i ndh 0.34 ± 1.25j

0.47 2.25 1.12 6.17

± ± ± ±

0.14k 0.93k 1.12k 1.08l

Each value represents the mean and standard deviation of samples from four producers in the market. Superscript in the column indicates significant or insignificant differences at P  0.05. nd e not detected.

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Table 4 HACCP Plan for the production of ice-kenkey. Critical control point

Hazard identified

Control measures

Critical limits

Monitoring procedure

Corrective Action

Maize used to make Fanti Kenkey

Chemical: Aflatoxins

Use aflatoxin free maize for kenkey preparation

Physical inspection of maize grains

Reject maizey and change supplier

Fanti kenkey

Chemical: Aflatoxins

Use freshly prepared kenkey

Physical inspection for mouldy kenkey

Reject kenkey and change supplier

Peanuts (raw material)

Chemical: Aflatoxins

Microbiological: Contamination with pathogens Microbiological: Contamination with pathogens from milling machine Physical: Pieces of metal from grinding teeth

Physical inspection for mouldy, discoloured grains Rapid testing e.g. ATP Meter/Strip

Reject peanuts

Breaking of kenkey into pieces; constituting

Use good quality peanuts free from aflatoxins Wear disposable gloves

Maximum limit of 15 mg/kg of aflatoxins for maize Maximum limit of 15 mg/kg of aflatoxins for maize Maximum limit of 2 e4 mg/kg of aflatoxins for peanuts Coliforms and E. coli ¼ 0, Total Plate Count <103 CFU/ml. Coliforms and E. coli ¼ 0, Total Plate Count <103 CFU/ml.

Milling

Packaging

Contamination with pathogens.

Wash and rinse milling machine with warm water (60
C) before use. Use stainless steel machine. Avoid handling of product with bare hands Bagging: Pasteurize the Constituted ice-Kenkey before packaging aseptically in sterile polythene pouches. or Bottling: Sterilize bottles and caps by boiling before filling with Constitute iceKenkey. Then pasteurize the bottled ice-Kenkey.

constituted ice-kenkey the recorded values were in the range of 0e2.55 mg/kg. The concentration of Zn in the ice-kenkey samples were between 0.47 and 6.17 mg/kg which is within the WHO limit of 10e75 mg/kg. Mn and Zn are essential metals and play an important role in biological systems and are important for maintaining health throughout life (Ma & Betts, 2000; Unak, Lambrecht, Biber, & Darcan, 2007). Pb was not detected in ice-kenkey samples from two of the markets and in the other two markets the mean concentrations were 1.25 and 0.34 mg/kg respectively. The levels were below the safe limit recommended by WHO. According to Dobaradaren et al. (2010) lead is toxic even at trace level. 3.4. The presence of aflatoxins in ice-kenkey The presence of aflatoxins has long been recognized as a hazard in kenkey (Amoa-Awua et al. 1998; Kpodo, Sorensen, & Jakobsen, 1996). The results of aflatoxin analysis showed high levels of aflatoxins in the ice-kenkey samples. The mean total aflatoxin concentration in samples from the four markets were 17.04, 7.99, 11.99 and 22.17 mg/kg for Madina, Ashaiman, MallamAtta and Agbogbloshie markets respectively (Table 3). These are high aflatoxn levels though only the mean values of the samples obtained from the Madina and Agbogbloshie markets exceeded the total maximum limit of aflatoxins set for maize in Ghana by the Ghana Standards Authority, i.e. 15 mg/kg (Ghana Standards Authority, 2003). Most of the aflatoxins were made up of aflatoxin B1, which accounted for 93.9%, 89.1%, 90.9% and 94.1% of the total aflatoxins respectively. Though only two samples were analyzed out of the 16 samples from each market, the results indicate that aflatoxin contamination of ice-kenkey sold in Ghana poses a high risk to consumers. It is therefore important that ice-

Pasteurize meal after milling

Rapid testing e.g. ATP Meter/Strip

Reject

No visible traces of any metal pieces in the milled meal

Inspection of grinding plates for rust before milling.

Reject

Coliforms and E. coli ¼ 0, Total Plate Count <102 CFU/ml.

Monitor temperature and time during pasteurization Rapid testing e.g. ATP Meter/Strip

Pasteurize product again if bottled

kenkey producers obtain kenkey from suppliers who have instituted control measures to prevent aflatoxin contamination of their products. 3.5. Poor manufacturing and hygienic practises observed in microscale production of ice-kenkey Several poor manufacturing and hygienic practises were observed which compromised the safety of the street vended icekenkey and needed to be addressed. Several of the producers worked in surroundings which were not conducive to produce safe food. The rooms were close to open drains with flowing sewage. The windows were often not covered with a mesh to keep out files and rodents from the production rooms. The rooms were not kept as clean as was necessary. Several of the operations were carried out manually and involved contact of the food with the hands of producers. The producers did not use disposable gloves and if they did not observe strict hygienic principles ended up contaminating the food. This was especially important during packaging when the producers used cups to fill ice-kenkey into polyethylene bags and plastic bottles. The producers and millers used several utensils and ladles which they washed with soap at the end of the day. These were never rinsed with warm water which would have helped to reduce contamination. Some producers resorted to washing their utensils with only water without any detergent. The millers did not also rinse their machines with warm water. There was no assurance that water used in milling and mixing the milled kenkey was of very good quality. In most instances pipe borne water was used but these were sometimes stored in tanks at the mills.

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Based on the observed unsatisfactory practices, a manual was developed for training ice-kenkey producers (Atter, Ofori, Anyebuno, Annan & Amoa-Awua. 2014). The first section of the manual describes basic elements of good manufacturing practices as a pre-requisite program related to facilities and personal hygiene. The second section describes a HACCP plan which details amongst others the control measures and monitoring procedures that the producers must follow to assure the safety of the product. The manual has been adopted by the Accra Metropolitan Assembly which in collaboration with the Food Research Institute, Accra has conducted training for 40 ice-kenkey producers in three districts in Accra. The HACCP plan is shown in Table 4 and the critical control points include the maize which is used to produce kenkey purchased by the ice-kenkey producers as raw material. Though this is outside the scope of operations of the ice-kenkey producers, its control is key to producing safe ice-kenkey with respect to aflatoxin contamination. Similarly roasted groundnuts used by some icekenkey producers is a critical control point. The control measure for groundnuts in the HACCP plan is based on the procedure for manual sorting of groundnuts developed by Galvez, Francisco, Villarino, Lustre and Resurreccion (2003) and also reported on by Chinnan, Anyebuno, Florkowski, and Resurreccion (2012). It involves slightly roasting shelled groundnuts to remove the skin and obtain blanched nuts. The blanched nuts allow easy identification and removal of those kernels which are infected by aflatoxin producing moulds. The other CCPs are the manual operations in which producers handle the product directly e.g breaking balls of kenkey into pieces as well as appropriate cleaning of the mill, utensils and bottles for packaging. 4. Conclusion The study showed the need to improve the safety of ice-kenkey production and vending in Accra. Manual operations in ice-kenkey production which involved contact of the product with the producers such as breaking up kenkey with hands exposed the product to contamination with pathogens. The use of maize and groundnuts as raw materials exposed ice-kenkey to aflatoxin contamination and required strict control. The work enabled a training manual to be developed which has been used to training ice-kenkey producers in Accra. References Amoa-Awua, W. K., Halm, M., & Jakobsen, M. (1998). HACCP system for African fermented foods: Kenkey. Taastrup: WAITRO, ISBN 87-90737-02-4. AOAC. (2005). Official methods of analysis of AOAC International (18th ed.). Gaithersburg, Maryland, USA: AOAC International. Atopla, R. (2006). Assessment of microbial quality of fanti kenkey in different packages. Higher National Diploma dissertation. Ghana: Accra Polytechnic. Atter, A., Ofori, H., Anyebuno, G. A., Annan, T., & Amoa-Awua, W. K. (2014). Training manual on ice-kenkey production. Accra: CSIR-Food Research Institute. CSIR-FRI/ MA/AA/2014/001. Barro, N., Bello, A. R., Itsiembou, Y., Savadogo, A., Ouattara, C. A. T., Nikiema, A. P., et al. (2007). Street-vended foods improvement: contamination mechanisms and application of food safety objective strategy: critical review. Pakistan Journal of Nutrition, 6(1), 1e10.

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