Investigation of Staphylococcus aureus Isolation and Thermonuclease Activity and Enterotoxin Formation in Some Dairy Desserts

Authors: MUSTAFA ALİŞARLI, YAKUP CAN SANCAK, LEVENT AKKAYA, CİHANGİR ELİBOL

Abstract: In this study, the isolation of Staphylococcus aureus from dairy desserts, and its thermonuclease activity and enterotoxigenic properties were investigated. A total of 175 samples were analyzed consisting of 100 pudding samples (sütlaç [rice pudding] 25, keşkül [milk pudding containing coconut] 30, supangile [chocolate pudding] 25, kazandibi [milk pudding slightly burned on the bottom] 20) and 75 cream pastries (butter-cream 25, chocolate-cream 25, fruit-cream 25). According to the analysis, S. aureus was found in a total of 30 (17%) samples in one sütlaç (4%), three keşkül (10%), four supangile (16%), and two kazandibi (8%) samples (10% of pudding samples; and six butter-cream (24%), ten chocolate-cream (40%), and four fruit-cream (16%) pastry samples of cream pastry samples). The thermonuclease activity of S. aureus (27%) strains isolated from 27 (90%) cream pastry samples was positive and an enterotoxin-producing capacity was determined in 11 samples (37%). Type A enterotoxin was found in seven samples: one keşkül, one supangile, one butter-cream pastry, three chocolate-cream pastry, and one fruit-cream pastry. Type C enterotoxin was seen in two samples; one supangile, and one chocolate-cream pastry. Type A/B mixed enterotoxins were seen in sütlaç and butter-cream pastries. All enterotoxin producing strains also have thermonuclease activities. In conclusion, if it is considered that foods contaminated with S. aureus after other microflora have been eliminated by heating play an important role in the occurrence of staphylococcal food intoxication, it is suggested that dairy desserts pose a potential health risk in terms of enterotoxigenic staphylococci, necessitating a serious control program concentrating especially on the hygiene of personnel and equipment.

Keywords: Dairy dessert, thermonuclease activity, enterotoxin, Staphylococcus aureus

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