Irradiation of ready meals for microbiological safety and shelf-life extension. 1. Microbiological quality of waakye and other ready-to-eat meals

Waakye bought from the open market and 14 meals prepared under the hazard analysis and critical control point (HACCP) plan were microbiologically investigated. The aerobic mesophilic count (AMC) (107 - 108 CFU g-1) and coliform count (106 - 107 CFU g-1) ) for complete waakye meals, including macaroni, fried fish, sauce and vegetable salad, exceeded the microbiological standards for such ready-to-eat meals. The AMC (101 - 104 CFU g-1) ) and coliform count (101- 102 CFU g-1) ) for all the ready meals prepared under HACCP and stored (-5 to 0 oC) for up to 5 days were within the standards. Potential pathogens isolated from waakye and the meals prepared under HACCP plan included Escherichia coli, Klebsiella spp., Serratia spp., and Enterobacter spp. Subsequent studies will exploit the potential of irradiation to eliminate pathogens and ensure the microbiological safety of ready-to-eat mealsWaakye (riz et haricot cuisinés ensemble) acheté de la vente libre ainsi que quatorze repas préparés sous le critique (ARPCC) étaient enquetés par la méthode microbiologique. Le compte d'aerobic mésophilique (107 - 108 CFU g-1) et le compte coliforme (106 - 107 CFU g-1) ) pour le repas de Waakye complet qui comprenait le macaroni, le poisson frit, la sauce et la salade de légumes dépassaient les normes microbiologiqes pour tels repas cuisinés. Le compte d'aerobic mésophilique (101 - 104 CFU g-1) ) et le compte coliforme (101 - 102 CFU g-1) ) pour tous les plats cuisinés préparés sous ARPCC et conservés au froid (-5 à 0 oC) pour 5 jours étaient aux niveaux requis. Les agents pathogènes potentiels isolés de waakye et des repas préparés sous le plan d'ARPCC comprenaient Escherichia coli, Klebsiella spp., Serratia spp., and Enterobacter spp. Les études à venir vont exploiter l'utilisation d'irradiation pour éliminer les agents pathogènes et assurer la sécurité microbiologique des repas cuisinés. Ghana Journal of Agricultural Science Vol. 39 (1) 2006: pp. 19-2

Radiation decontamination and disinfestation of salted dried tilapia fish (koobi)

Salted dried tilapia (Oreochromis niloticus) fish locally called koobi was investigated with the view of establishing the effective radiation dose for controlling microbial and insect activity on the product. Total viable count (TVC) of market samples of koobi ranged between log 10 4.11 - 6.78 cfu/g, whilst mould and yeast count ranged between log 10 1.38-3.38 cfu/g. Staphylococcus aureus counts ranged between log 10 2.85 - 4.15 cfu/g. After 4 weeks' storage under ambient conditions, total viable count increased to log 10 7.5 ± 2.5 cfu/g. Significant reduction in total viable count was observed after treatment with gamma radiation. A least square regression fitted through the data points indicated that 1.3 kGy would be required to reduce the microbial population on the product by one log cycle. Insects and pink colonies of halophilic bacteria were observed on all the nonirradiated samples after 4 weeks' storage. Treatment with 3 kGy gamma radiation eliminated all insect forms, while microbial population was controlled with TVC ranging between log 10 1.9 ± 1.1 and log 10 2.7 ± 1.6 cfu/g throughout the 16 weeks' storage period. The proliferation of halophilic bacteria and subsequent appearance of pink colonies on irradiated koobi was suppressed until the 16th week. Irradiation, therefore, extended the shelf-life of koobi from 4 to 15 weeks. Ghana Journal of Agricultural Science Vol. 37 2004: 85-9

Microbiological Studies Of Macaroni And Vegetable Salads In Waakye, A Local Street Food

The microbiological quality of macaroni and vegetable salads served with waakye, was investigated. Aerobic mesophiles counts (AMC), coliforms counts (CC) and moulds and yeasts counts (MYC) were estimated, and the coliform profiles for different samples of macaroni (raw, local/ imported, laboratory-cooked) served with waakye, and vegetable salads served with waakye were determined. Raw macaroni (local and imported) had AMC of 3.6 and 3.0 log10 CFU/g, MYC of 1.9 and 1.0 log10 CFU/g and no CC, respectively. Laboratorycooked local samples had AMC of 2.4 log10 CFU/g and 3.3 log10 CFU/g (after 4 h storage) and no MYC. Macaroni obtained from vendors had AMC mean of 3.1-8.4, CC mean of 2.5-7.3 and MYC mean of 0- 4.1 log10 CFU/g depending on time of sampling. Vegetable salads sampled at early and late morning had AMC of 6.9 and 7.6, CC of 5.7 and 6.4, MYC of 4.9 and 5.4 log10 CFU/g, respectively. Six coliforms were detected on macaroni and three were detected in addition to Salmonella spp. on vegetable salads. No significant difference was recorded in the microbial load of raw local and imported macaroni. Cooking improved the microbial quality of raw macaroni (AMC of 2.4 log10 CFU/g). Generally, there were increases of 3-5 log cycles in the AMC, CC and MYC in macaroni sampled from waakye vendors in the morning (early and late) compared to those at dawn. Although the nature of raw macaroni and its cooking are adequate, cross-contamination from vegetable salads during the holding and bulk display periods cause deterioration in microbial quality of macaroni in waakye. There is the need to educate vendors on simple preventive steps of keeping food hygienically safe.La qualité microbiologique de macaroni et de macédoine de légumes servis avec waakye était étudiée. Les comptes mésophiles aerobie (CMA), les comptes de coliformes (CC) et les comptes de moisissures et de levures (CML) étaient estimés et les profils de coliforme de différents échantillons de macaroni (cru, local/importé, cuit au laboratoire et waakye) et les macédoines de légumes servis avec waakye étaient déterminés. Le macaroni cru (local et importé) avait les CMA de 3.6 et 3.0 log10 CFU/g CML de 1.9 et 1.0 log10 CFU/g, et aucun CC respectivement. Les échantillons locaux cuits au laboratoire avaient CMA de 2.4 log10 CFU/g et 3.3 log10 CFU/g (après 4-heure de stockage) et nulle CML. Le macaroni obtenu de marchandes avait CMA moyen de 3.1 à 8.4, CC moyen de 2.5 à 7.3 et CML moyen de 0 à 4.1 log10 CFU/g selon le temps d'échantillonage. La macédoine de légumes échantillonée au début et à la fin de la matinée avait respectivement CMA de 6.9 et 7.6, CC moyen de 5.7 et 6.4, CML de 4.9 et 5.4 log10 CFU/g. Six coliformes étaient dépistés sur le macaroni et 3 étaient dépistés en plus de Salmonella spp. sur la macédoine de légumes. Aucune différence considérable n'était enregistrée de la quantité microbienne de macaroni cru, local et importé. La cuisson améliorait la qualité microbienne de macaroni cru (CMA de 2.4 log10 CFU/ g). En général il y avait des augmentations de 3 à 5 cycles log dans le CMA, CC et CML de macaroni échantillonné de marchandes de waakye dans la matinée (au début et à la fin) comparé à ceux de l'aube. Bien que la nature de macaroni cru et ses cuissons soit adéquate, la contamination croisés de macédoine de légumes pendant le stockage et les périodes de l'étalage en gros provoque la détérioration dans la qualité microbienne de macaroni en waakye. Il est nécessaire d'éduquer les marchandes sur les mesures préventives simples de garder la nourriture hygiéniquement favorable à la santé. Ghana Journal of Science Vol. 47 2007: pp. 3-

Determination of DB10B values of single and mixed cultures of bacteria after gamma irradiation

The DB10B value of bacteria represents the absorbed radiation dose required to inactivate 90 % of a viable populati-on or reduce the population by a factor of 10. DB10B values of 3 bacterial isolates (Escherichia coli, Staphylococ-cus aureus and Salmonella parathyphi B) were determined using single and mixed cultures to assess the effect of microbial competition on radiosensitivity. The isolates were inoculated into wakye substrate and exposed to γ-radiation doses of 0, 100, 300, 450, 600, 750, 850 Gy from a P60PCo source at a dose rate of 2.20 kGy/h in air. Enumeration of survivors of the isolates was carried out using serial dilution and pour plate methods. The survi-ving fraction of isolates decreased with increased irradiation doses. DB10B values of E. coli, S. aureus and S. parat-hyphi B were respectively 0.27, 0.33 and 0.44 kGy when inoculated as single cultures, and 0.24, 0.28 and 0.32 kGy respectively when inoculated as mixed cultures. DB10B values were lower for mixed cultures compared to single cultures, which might indicate reduced resistance to γ-radiation as a result of competition among the isolates. Microbiological challenge tests based on the DB10B values may result in delivery of higher irradiation doses, but the extra dose could serve as safety margin to enhance the food preservative capacity of radiation processing

Economic and market analysis of swine rearing and pork production in Ghana

Swine rearing and pork production has recently attracted the growing interest of Ghanaian farmers who seek diversification of enterprises and existing farmers looking for alternatives following a period of low profitability. Piggery was established to combine science and technology to generate innovations for anyone seeking to establish a new pig production enterprise. Results show that since 2008 to 2013, pork prices in Ghana rose rapidly between 115-120%. Also the rate of returns was higher at 43.62% compared to bank interested rate. Feed, as a percentage of total costs, were minimised from 70% to 55% with integrated lactobacillus brewer spent malt as supplement to formulated feed. The piggery project was highly successful and invested capital was recouped within two years of project take-off. Collaborating with other farms, organisations and entrepreneurs, a lot of research innovations in the area of improving feed cost, animal nutrition, waste management practices, and breeding have been generated and shared with both small and large-holder pig farmers. In all aspect of the farm management, results achieved so far especially with pork carcass quality and profit margins are encouraging which have led to the expansion of the piggery project.Kwamina Ewur Banson, Josephine Nketsia-Tabiri, Kweku Anno, and Emmanuel Kofi Dagbu

Effect of irradiation and insect pest control on rots and sensory quality of two varieties of stored ware white yams in Ghana

The coffee bean weevil, Araecerus fasciculatus Degeer (Coleoptera: Curculionidae) is associated with rots in stored yam tubers. The current study was designed to assess the effect of irradiation and other insect pest control strategies on rots and sensory quality of stored yams. 450 tubers each of two varieties of white yam (Dioscorea rotundata Poir) namely ‘Puna’ and ‘Asana’ were divided into two groups with half irradiated and the other half not irradiated. The two groups were then further divided into three sub-groups. The first sub-group was treated with a chemical insecticide ‘Superguard’ (400g/l Pirimiphos-methyl and 75 g/l Permethrin) against A. fasciculatus infestation whilst the second sub-group was placed in insect-proof boxes with no chemical treatment. The third sub-group was neither chemically treated nor placed in insect-proof boxes. They were all then stored in improved yam barns for four months after curing in February. Sprouts that developed on the non-irradiated tubers were broken off weekly. They were examined for rots and weight loss over the storage period. Sensory evaluation was conducted on the tubers at the end of storage to determine whether the treatments affected their sensory quality. It was observed that the irradiation and chemical insecticide treatments did not have significant effect (p>0.05) on percent rots and weight loss while the effect of storage on these parameters was significant (

The use of gamma radiation for the preservation of kola nuts

Kola nuts wrapped with Mitragyna stipulosa (Akan: subaha) leaves and stored in baskets (traditional method) and irradiated with Co-60 gamma rays with absorbed doses ranging from 0.10 to 0.50 kGy at a dose rate of 0.171 kGy/hr to control kola weevils (Balanogastris kolae) during storage. The number of nuts per treatment ranged between 20 and 1353, and the ambient storage temperature fluctuated between 16.5EC and 37.5E C. Gamma radiation suppressed the development and emergence of kola weevils that destroy the nuts in storage. Whilst no live insects were found in the treated samples, up to 48 live weevils were counted per packet in the control treatment at 28 days in storage. Consequently, nut infestation in the control was about 98.4%. Fungal deterioration of both irradiated and unirradiated kola nuts was observed. Weight loss in kola nuts irradiated at 0.25 and 0.50 kGy and stored for 84 days after irradiation was 18.2% and 19.2%, respectively, whilst comparable loss from the control treatment was 39.9%. Weevils fed with treated and untreated nuts did not show any preferences and differences in growth. A panel of tasters did not detect any differences between treated and untreated nuts. JOURNAL OF THE GHANA SCIENCE ASSOCIATION Volume 2 No. 3 (2000) pp. 184-19