Hazard analysis and critical point identification at Abiss slaughter house in Alexandria.

The purpose of this study is to identify potential hazards associated with animal slaughtering and how could these affect the microbiological count of carcasses, and to describe the use of HACCP to improve the microbiological count of fresh meat. Hazards were detected by observing the different steps of animal slaughter and then filling a prepared red meat slaughterhouse score sheet. The microbiological load was determined through testing 112 swab samples taken from the surface of carcasses in addition to 21 samples from hands, knives, tap water and air. Results showed that most of the parameters of the score sheet observed for evaluating hygienic operations were classified as being of maximum risk C. The aerobic plate count enterobacteriacea, mold and yeast and staphylococci increased insignificantly after cutting to 9.7x10(2), 6.4x10, 2.6x10(2), and 3.7x10 cfu/cm2, respectively. Washing of the carcasses decreased counts insignificantly to 6.4x10(2), 2.0x10, 1.7x10(2), and 2.0x10 cfu/cm2, respectively. The microbiological count of air samples at quiet hours were lower insignificantly than those at busy hours. Subsequently a HACCP system was designed based on these microbial studies, observations of current practices within the slaughterhouse and relevant literature and following the 7 principles of HACCP.

Effect of non-fat dry milk on recovery of staphylococcal thermonuclease from foods.

Modification of the method of Tatini et al. (1976) by addition of non-fat dry milk (NFDM) to food samples and subsequent acid precipitation at pH 3.8 enhanced the recovery of staphylococcal thermonuclease (TNase) from most of 37 foods tested. The modified TNase assay method allowed detection of 10 ng (0.002 units) of the enzyme per gram of each of the following foods: ground beef, boiled egg products, whey powder, fruit-containing yogurt, dressings and spreads, potato and egg salads, and pastas, all of which gave false-negative results without NFDM.

Evaluation of staphylococcal thermonuclease (TNase) assay as a means of screening foods for growth of staphylococci and possible enterotoxin production.

Samples of food, naturally and artificially contaminated with Staphylococcus aureus, were analyzed for enterotoxin and thermonuclease (TNase). With the exception of egg, all naturally contaminated foods with detectable amounts of staphylococcal enterotoxin were positive for TNase. The enzyme was also present in the majority of foods with over 1 million S. aureus cells per gram. In artificially contaminated foods. TNase was detected in all samples except egg, acidic foods in which growth of S. aureus was suppressed, and some samples of raw ground beef. Recovery of TNase was influenced by the type of food.

The effect of compounds which degrade hydrogen peroxide on the enumeration of heat-stressed cells of Salmonella senftenberg.

Greater than 90% of heat-stressed cells of Salmonella senftenberg failed to grow on trypticase soy agar. Adding to this medium compounds which are capable of degrading hydrogen peroxide allowed growth of the heat-injured cells. These compounds did not stimulate growth of heated cells of Streptococcus faecium, an organism which does not possess catalase.