OCCURRENCE OF CLOSTRIDIUM PERFRINGENS IN GROUND BEEF AND GROUND TURKEY EVALUATED BY THREE METHODS1

A rapid and effective method (Fung's Double-tube method) for estimating low numbers of Clostridium perfringens from ground beef and ground turkey has been investigated and compared to Oxyrase Enzyme and Gas Pak Anaerobic System methods. C. perfringens was detected with one or more of the methods in 64 (54%) of 118 ground beef samples and 40 (73%) of 55 ground turkey samples. Fung's Double-tube showed 94 (54%) out of 173, Oxyrase Enzyme 77 (45%) out of 173, and Gas Pak Anaerobic System 73 (42%) out of 173 ground beef and ground turkey samples to be positive for C. perfringens. Fung's doubletube showed significantly (p <0.05) higher number of samples positive for C. perfringens in these samples than other two methods. The results indicated a much higher occurrence of C. perfringens in ground turkey (73%) than in ground beef (54%). Furthermore in order to compare the efficiency of these methods in enumerating number of C. perfringens cells during storage, some samples were kept at room temperature (23°C) for 7 days. The number of C. perfringens increased from 44/g up to 1.3x10⁹/g as enumerated by Fung's Double-tube.     

VARIATION IN THE SELENIUM CONTENT OF INDIVIDUAL BRAZIL NUTS

Brazil nuts are high in selenium content relative to other human foods. Since the limits between human selenium essentiality and toxicity are narrow, it is important to know the variation in selenium content of individual nuts. Analysis was performed on 72 individual nuts obtained in stores as shelled nuts in bulk and shelled and unshelled nuts in packages. Their average selenium content was 14.66 ppm with a range of 0.2 to 253.0. The agronomic and health aspects of these findings are discussed.     

POST-MORTEM ISOMETRIC TENSION CHANGES AND SHORTENING IN TURKEY MUSCLE STRIPS HELD AT VARIOUS TEMPERATURES

SUMMARY: A study of the physical changes associated with rigor mortis in breast muscle was undertaken to assess the factors that may influence ultimate tenderness. Isometric tension changes and shortening were measured at temperatures 2–37°C. These changes were measured while holding the muscle strips in a phosphate buffer, pH 7.2. Isometric tension was measured by transducers and recorded on a physiograph. A pattern of tension development and gradual relaxation has been demonstrated to occur post-mortem in strips of turkey breast muscle held isometrically. The time to maximum tension development occurs in 3.85 ± 0.19 hr and is not linearly related ( P <.05) to temperature. The amount of maximum tension developed averaged 25 g/cm² and was significantly ( P < .05) related to temperature. Relaxation to about 50% of maximum occurs in 18 hr. The amount of shortening that occurs post-mortem is linearly related ( P < .01) to temperature. No "cold shortening" of turkey breast muscle was evident.     

THE OCCURRENCE, HEMOLYTIC ACTIVITY AND ANTIBIOTIC SUSCEPTIBILITY OF MOTILE AEROMONAS SPP. ISOLATED FROM MEAT AND MILK SAMPLES IN TURKEY

Research was carried out to detect the incidence of motile Aeromonas species (A. hydrophila, A. caviae, A. sobria) in a variety of raw meat products (minced meat and chicken) and milk samples (raw and pasteurized) commonly consumed in Ankara. Motile Aeromonas species were isolated from 51.8% of samples detected; these were 40 (67.7%) of the 59 samples of minced meat, 20 (86.9%) of the 23 samples of chicken, 75 (47.7%) of the 157 samples of raw milk and 5 (16.0%) of the 31 samples of pasteurized milk. The dominant species were A.hydrophila and A.sobria in the meat samples, while A. hydrophila was the only isolated species in the milk samples. The strains identified as A. sobria or A. hydrophila were the stronger producers of hemolysin, whereas the A. caviae strains were nonhemolytic. The resistance of isolates to eight antibiotics was determined using the Kirby Bauer disc diffusion assay (Ciprofloxacin, Ceftazidime, Ampicillin, Cefixime, Cefoperazone, Erythromycin, Trimethoprim/sulfamethoxazole, Ceftriaxone). All aeromonads isolates (100%) were susceptible to ciprofloxacin but resistant to (100%) ampicillin and erythromycin. We found out that motile Aeromonas species are commonly present in milk and meat samples investigated in Turkey, which may pose a health problem to consumer. In addition, ciprofloxacin, cefoperozone, and ceftriaxone are suitable drugs that can be used in the treatment of Aeromonas-associated infections, particularly in the immunocompromised, elderly people and young children.     

OCCURRENCE OF MOLDS IN FRESH CHEESES

The purpose of our work was isolation, enumeration and identification of molds in fresh cheeses. A total of 112 cheese samples were obtained from different retail markets in Santa Cruz de Tenerife. Of the samples, 57.2% were positive for industrially craft produced cheeses. The values for the industrially produced cheeses ranged between 10² and 10⁶ CFU/g, for the craft produced cheeses the corresponding values were 10²-10⁷ CFU/G and 4.4x103. The genera identified most often in both types of cheeses were Geotrichum and Penicillium with 49.4 and 29.1% of isolates, respectively. Species of the Aspergillus genus, the main producer of aflatoxins, was detected in 1.3% of the total samples analyzed. Nonetheless, the presence of such genera as Fusarium, Cephalosporium, Cladosporium, etc. is considered to be undesirable, as they are capable of producing other mycotoxins related to specific pathological processes.     

COMBINED EFFECT OF pH AND HEAT TREATMENT ON DEGRADATION OF AFLATOXINS IN DRIED FIGS

Dried figs are sensitive commodities to aflatoxin contamination. Although preventive methods are the logical solution to aflatoxin problems, once the product is contaminated, decontamination procedures are inevitable. In this study, the effectiveness of a procedure consisted of acidification/alkalization, and heat treatment in degradation of aflatoxins was evaluated. The pH of dried fig extracts was adjusted to 3.1, 3.5, 6, 8 or 10 by adding acid or base. Extracts were heated at 50, 75 or 98C for 1 or 2 h, and then the residual aflatoxin B₁, B₂, G₁ and G₂ were determined. The highest level of degradation for aflatoxin B₁ (97  ±  1%) and B₂ (87  ±  1%) were observed at pH 10 in samples heated at 98 and 50C, respectively. Some treatments resulted in 100% degradation of aflatoxin G₁ and G₂ so that they could not be detected.

PRACTICAL APPLICATIONS

Aflatoxin contamination is a serious problem for a number of processed and non-processed foods, including dried figs. This not only presents severe risks to human and animal health but also causes economic problems for countries such as Turkey, U.S.A., Greece and Spain, which produce and export dried figs. It is clear that detoxifying studies are unavoidable when the amount of crop contaminated by toxins is considered. Therefore, the food industry is in search of applications that are effective in mycotoxin detoxification and adaptable to food processes. This is the first report on degradation of aflatoxins in naturally contaminated dried figs by such a promising method.     

MICROBIOLOGICAL QUALITY OF WHEAT STORED UNDER DIFFERENT CONDITIONS IN TURKEY

Four different types of wheat storage systems are widely used in the Marmara region. The existing storage conditions were studied and changes in the microbiological quality of the stored wheat under these conditions were assessed.
Depending on the external conditions, ambient temperatures and relative humidities in the stores were 17–26°C and 50–65% RH during summer and 3–10°C and 62–83% RH during winter, respectively. The low relative humidity level during harvesting and subsequent storage was adequate for obtaining low levels of moisture content and water activity in the produci for safe storage. The increase in relative humidity of the air during winter months did not affect the moisture content of the product considerably and the low temperature prevented mold growth. Therefore, all of the four different storage facilities were suitable for safe storage of grain for a period of one year without significant losses in quality due to microbiological load.     

ESTIMATION AND OCCURRENCE OF ACETALDEHYDE IN BEER

A sensitive routine quantitative method has been developed which determines acetaldehyde in beer. The method is suitable for the measurement of acetaldehyde, its bisulphite addition compound and acetal, with only limited interference from other aldehydes. The examination of a representative selection of beers shows that large differences of acetaldehyde can occur in beers of a similar type. Beers which have been sweetened by the addition of priming sugar vary widely in their acetaldehyde content, many being above the 25 ppm taste threshold. The acetaldehyde content has been shown to vary with both the quantity and point of addition of sulphur dioxide when this is used as a preservative or antioxidant.