PSYCHROTROPHIC SPOILAGE MOULDS IN IMPORTED FROZEN BEEF CUTS

Imported frozen meat specially frozen beef cuts are used mainly as raw material in meat products in Egypt. Therefore, microbiological qualification of such frozen meat is very important due to the late usage. Some defects as formation of black, green and white spots are formed on the end products, the causative organisms originate mainly from the raw material. Contamination of imported frozen meat with mould spores can be attributed to the mishandling of meat from time of their arrival until it reached different cold- stores as many authors mentioned that deep freezing (until -18°C) has no significant destructive effect upon mould spores as they can resist cold storage- (Monvoisin, 1918; Shonberg, 1954; Frank, 1966; Frazier and Westhoff, 1979; Gill et al., 1981; Gill and Lowery 1982 and Mansour, 1986). Mycological examination of imported frozen beef and hunted meats affected with black spots revealed that the most predominant moulds were Cladosporium herbarum, besides; Penicillium, Mucor, Phycomyces, Verticillium and Oospora (Berger, 1912 and Silva, 1913). Bidault (1921 & 1923) examined frozen meat and isolated the following genera; Penicillium crustaceum, Chaetostylum fresenii, Thamidium elegans, Hormodenderum cladosporiorides (Cladosporium cladosporioides), Sty- sanus stemonitis and Cladosprium herbarum. Empay and Scott (1939) examined mycologically beef carcase surface and incubated the plates at + 20°C and 1°C. At the first temperature the most predominant moulds were Fusarium, Alternaria and Cladosporium while at the 2nd one (-1°C) were Penicillium followed by Mucor, Cladosporium, Alternaria, Sporotrichum and Thamnidium. Hadlok (1970 & 1972) isolated the following mould genera from frozen meat and frozen foods: Penicillium, Mucor, Thamidium, Cladosporium, Monilia, Geotrichum, Trichothecium and Chaetostylum. Baxter and Illiston (1976) examined slaughter area, Boning room, Freezer, Chiller, carcases of sheep, beef and pig for the presence of psychrotrophic fungi and incubated the inoculated plates at 4 deg * C for 4-5 weeks and isolated the following moulds; Penicillium expan sum, Cladosporium herbarum, Cladosporium cladosporio- ides, Chrysosporium pannorum, Epicoccum purpuroscens, Rhizoctonia sps., Ascomycete, Mucor hiemalin and Alternaria alternata. Beuchat (1978) recorded that some species of Penicill- ium namely P. brvicompactum, P. cyclopium, P. ruber- ulum and P. expansum can grow on cold stored foods at temperatures below - 2 deg˚c. Fahmy (1986) mentioned that the most frequent mould genera isolated from frozen meat were: Aspergillus, Penicillium, Cladosporium, Mucor, Trichoderma, Alter- naria, Rhizopus, Geotrichum, Cephalosporium, Fusarium, Thamidiuim, Botrytis, Syncephalastrum, Pullularia, Spo- rotrichum carnis, Monilia, Helmintho-sporium and other unidentified mould genera. Gracey (1986) reviewed the moulds responsible for spoilage of chilled and frozen meats, species of clado- sporium (black spot), species of Penicillium (blue green spots), Thamnidium, Mucor, Rhizopus (Wiskers) and Chrysosporium (white spot). Refai et al. (1991) isolated the following genera from quarters of chilled meat: Aspergillus, Cladospo- rium, Alternaria, Curvularia, Helminthosporium, Pen- icillium, Paecilomyces, Scopulariopsis, Mucor, Rhizo- pus, Fusarium, Acremonium and Geotrichum. The term "Cold-growing microorganisms" has been vari- ed and interferred. The definition of Ingraham and Stockes (1959), Eddy (1960) as well as Gounot (1976) for differentiation between the "psychrophiles" and "psychrotrophs" is the first one in those microorga- nisms which have an optimum temperature for growth less than 20 deg * C and the second those which have an optimum temperature for growth at 29 deg ˚ c or above. Morita (1975) suggested that the term "psychrophiles" should be used only for those microorganisms which have an optimal temperature for growth at about 15 deg ˚ c or lower and maximal temperature for growth at about 20 deg ˚ C and a minimal temperature for growth at mathfrak 0 deg ˚ C or below. The same author added that any microorganism which is able to grow at low temperature but not meet- ing the aforementioned criteria should be referred to as "psychnotophs". The authors herein followed the definition of Morita (1975) and used the term "psychrotrophic" microorganisms "Moulds" which can grow at low temperature. The aim of the present work was to investigate the imported frozen beef cuts for the presence of the psychrotrophic spoilage moulds.