Microbial Quality Control of Raw Ground Beef and Fresh Sausage in Casablanca (Morocco)

Article excerpt

* In this study, samples of raw ground beef (n = 150) and fresh sausage (n = 100) were collected randomly from butcheries, supermarkets, and fast-food shops, in Casablanca, Morocco.

* Two types of meat product samples were considered, one with spices (n = 115) and other without spices (n = 135).

* All the samples were analyzed for the presence of the following bacteria:

-- Escherichia coli,

-- Staphylococcus,

-- Clostridium perfringens,

-- Salmonella, and

-- Listeria monocytogenes.

* E. coli strains were further typed by pulsed-field gel electrophoresis (PFGE), Operon O, and characterized for virulence genes by polymerase chain reaction (PCR).

* Foodstuffs such as ground meat and fresh sausages are a significant portion of the diet of a large active population in Morocco.

* These products are highly perishable, with a pH value not lower than 5.5 and water activity ([a.sub.w]) equal to or higher than 0.97.

* Since no fermentation process takes place during storage at 4[degrees]C, the hygienic quality of the raw materials is the main factor affecting the final value of the product.

* In this paper, the authors describe the hygienic quality of ground beef and fresh sausages produced in Casablanca, with the following objectives:

-- (i) to determine the prevalence and levels of pathogenic and nonpathogenic bacteria present in these products,

-- (ii) to analyze the effect of spices and herbs;

-- seasonality; and

-- location distribution on the prevalence of such microorganisms, and

-- (iii) to screen pathogenic strains of E. coli by molecular microbiology methods.

* From all samples tested, S. aureus was isolated in 25 (16.7%) samples of ground meat and 18 (18%) in fresh sausages.

* Just two strains of all strains isolated (5%) were ADNase (antideoxyribonuclease) positive.

* From all samples tested, C. perfringens was isolated in 47 samples (18.8%), 29 in ground meat (19.3%), and 18 in fresh sausages (18%).

* The majority of these positive samples were associated with added spices in ground beef (26.8%), as opposed to the 12.7% for ground meat without spices.

* For fresh sausage samples, the occurrence of C. perfringens was in 32.1% of samples with spices and in only 2.3% of samples without spices.

* The statistical analysis of the data obtained revealed that the effect of the hot season and the addition of spices were significant (p < .05) on the increasing charge of

--APCs,

--fecal coliforms, and

--E. …