Effect of gamma irradiation on microbial quality of minimally processed carrot and lettuce: A case study in Greater Accra region of Ghana

The increasing demand for fresh fruits and vegetables and for convenience foods is causing an expansion of the market share for minimally processed vegetables. Among the more common pathogenic microorganisms that can be transmitted to humans by these products are Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella. The aim of this study was to evaluate the microbial quality of a selection of minimally processed vegetables. A total of 181 samples of minimally processed leafy salads were collected from retailers in the city of Sao Paulo, Brazil. Counts of total coliforms, fecal coliforms, Enterobacteriaceae, psychrotrophic microorganisms, and Salmonella were conducted for 133 samples. L. monocytogenes was assessed in 181 samples using the BAX System and by plating the enrichment broth onto Palcam and Oxford agars. Suspected Listeria colonies were submitted to classical biochemical tests. Populations of psychrotrophic microorganisms >106 CFU/g were found in 51% of the 133 samples, and Enterobacteriaceae populations between 105 and 106 CFU/g were found in 42% of the samples. Fecal coliform concentrations higher than 102 CFU/g (Brazilian standard) were found in 97 (73%) of the samples, and Salmonella was detected in 4 (3%) of the samples. Two of the Salmonella-positive samples had <102 CFU/g concentrations of fecal coliforms. L. monocytogenes was detected in only 1 (0.6%) of the 181 samples examined. This positive sample was simultaneously detected by both methods. The other Listeria species identified by plating were L. welshimeri (one sample of curly lettuce) and L. innocua (2 samples of watercress). The results indicate that minimally processed vegetables had poor microbiological quality, and these products could be a vehicle for pathogens such as Salmonella and L. monocytogenes.

Download Full-text

Effect of Gamma Irradiation Treatment and Storage on Physico-chemical, Microbial and Sensory Quality of Minimally Processed Pineapple (Ananas comosus)

British Journal of Applied Science & Technology ◽

10.9734/bjast/2014/10361 ◽

2014 ◽

Vol 4 (19) ◽

pp. 2752-2761 ◽

Cited By ~ 2

Author(s):

Mavis Owureku-Asare

Keyword(s):

Gamma Irradiation ◽

Sensory Quality ◽

Ananas Comosus ◽

Minimally Processed ◽

Physico Chemical ◽

Irradiation Treatment ◽

And Storage

Download Full-text

Effect of low dose gamma irradiation and refrigeration on the chemical and microbial quality of shrimp (Penaeus monodon)

INTERNATIONAL JOURNAL OF PROCESSING AND POST HARVEST TECHNOLOGY ◽

10.15740/has/ijppht/8.2/131-138 ◽

2017 ◽

Vol 8 (2) ◽

pp. 131-138

Author(s):

B. MANJANAIK ◽

VEENA SHETTY

Keyword(s):

Gamma Irradiation ◽

Low Dose ◽

Penaeus Monodon ◽

Microbial Quality

Download Full-text

Sensory and Microbial Quality of Chicken as Affected by Irradiation and Postirradiation Storage at 4.0°C

Journal of Food Protection ◽

10.4315/0362-028x-60.7.761 ◽

1997 ◽

Vol 60 (7) ◽

pp. 761-770 ◽

Cited By ~ 43

Author(s):

HAMZA M. ABU-TARBOUSH ◽

HASSAN A. AL-KAHTANI ◽

M. ATIA ◽

ATEF A. ABOU-ARAB ◽

ADNAN S. BAJABER ◽

...

Keyword(s):

Gamma Irradiation ◽

Shelf Life ◽

Additional Benefit ◽

Chicken Breast ◽

Microbial Quality ◽

Sensory Acceptability ◽

Unirradiated Control ◽

Campylobacter Species ◽

Microbiological Analyses

Chickens were subjected to gamma irradiation doses of 2.5, 5.0,7.5, and 10.0 kGy using a semi-commercial gamma irradiation facility. The irradiated and unirradiated (control) chickens were stored at 4.0°C, and samples were drawn at day 0 and at 3-day intervals up to 21 days for sensory and microbiological analyses. All irradiation doses (2.5 to 10.0 kGy) had little effect on the sensory acceptability (appearance, odor, texture, taste) of both raw and cooked chicken (breast and thigh). Irradiation extended the time during which these characteristics were acceptable. Moreover, juiciness and tenderness of cooked chicken were only slightly affected by irradiation, and chickens were not rejected even after 21 days of storage. A dose of 2.5 kGy seemed adequate to extend the shelf life of chicken by 12 days, and increasing the dose level above 2.5 kGy gave little if any additional benefit as far as total and psychrotrophic bacterial counts are concerned. Moreover, the dose of 2.5 kGy was enough to destroy Salmonella, Yersinia, and Campylobacter species and coliforms. The study also showed that yeasts of the genera Candida, Saccharomyces, and Alternaria started to grow on day 12 in samples treated with ≥5.0 kGy, but not in samples treated with <5.0 kGy.

Download Full-text