In this study a comparison was made of recovering bacteria from stainless steel, plastic, wood, agar and meat surfaces. Sampling was performed using the agar contact and swab methods. The results indicated that for a flat, firm surface the contact plate method was more suitable, considering both recovery and repeatability. Swabbing was, by contrast, better for flexible and uneven surfaces and for heavily contaminated surfaces. Bacteriological guidelines are suggested for the hygienic evaluation of surface contamination of meat carcasses and for working surfaces in meat processing plates.

No abstract

A total of 276 Staphylococcus aureus strains isolated from routine sampling, food poisoning outbreaks, and mastitic milk were examined for production of enterotoxins A, B, C, D, and E. Quantitative determination of thermonuclease was carried out from the dialysis sac culture supernatant fluids obtained during the enterotoxin assay. The toxic properties of the strains were compared with other biochemical properties (coagulase, phosphate, production of pigment, and hemotoxin) and with their sensitivity to antibiotics and phages. Fifty one percent of the strains examined produced enterotoxin, and of the toxigenic strains 53% produced enterotoxin A, 4% produced B, 38% C, and 20% D. Production of enterotoxin E was not observed with any of the strains. Production of thermonuclease averaged 19.4 and 25.5 μg/ml for toxigenic and non-toxigenic strains, respectively. All toxigenic strains produced coagulase, 98% produced phosphatase, 92% hemotoxin, and 79% yellow or orange pigment. Of the toxigenic strains isolated from food, 56% belonged to phage group III, and of the toxigenic strains isolated from mastitis cases 31.4% belonged to phage group M and 21% to phage group III. Resistance to antibiotics was slightly more widespread among the toxigenic than the non-toxigenic strains.

Different amounts of enterotoxin A-, Band nd C,-producing staphylococci were added to dry sausage prepared by normal processes, either alone or in conjunction with a starter culture (micrococci and lactobacilli). The sausage was examined after 0, 3, 7, 14, and 30 days for staphylococci, micrococci, and lactobacilli, and measurements were made ofwater activity, pH, enterotoxin, and thermostable nuclease. The results showed that in the absence of starter culture measurable amounts of entertoxin A were formed in a 200-g sample of dry sausage in 3 days, the level of Staphylococcus aureus infection being over 106 cells/g. Enterotoxin B was not found, although the total number of staphylococci was over 108 cells/g. Enterotoxin C1 was observed when the Staphylococcus count was about 8 x 107 cells/g, but was no longer detectable after 7 days. The starter culture

Thin-layer chromatographic methods were used for the determination of patulin in 166 samples of apple products. A new two-dimensional method, utilizing benzene-methanol-acetic acid as the first developing solution and tolueneethyl acetate-formic acid as the second, was developed for quantification of patulin in apple juice concentrates. The patulin concentrations in other samples were assayed using the conventional AOAC method. Of the 64 lots of apple juice concentrate imported (0.9 million kg), 13 lots (0.2 million kg) contained patulin, at concentrations of SO-690 .ng/L. Of 14 apple flavor lots studied (0.2 million kg), patulin was found in 3 (0.1 million kg), at concentrations of 6-1770 pg/L. Of 20 samples of home-made apple juice examined, 8 were found to contain patulin, with concentrations between 30 and 16,400 pgg/L. The frequency of occurence of patulin in commercial and home-made apple juices was 20 and 40% respectively. In home-made apple jam which had become mouldy during storage, patulin was found to diffuse to all levels of the jam. Ten samples of apples spontaneously affected by mould in the laboratory contained patulin, indicating the abundance of patulin-producing fungal strains. On the basis of the results obtained the patulin risk in home-made apple products appears to be greater than in commercial apple products.