Morphological characterization of a bacteriophage isolated from the Lactobacillus plantarum portion of a commercial meat starter culture showed that the isolate, phage fri, belonged to the Bradley group A bacteriophages. It had a regular six‐sided head (90 nm diameter), and a contractile tail (190 nm in length). Short tail fibres were observed at the distal end of the sheath. Fluorescent staining with acridine orange indicated that phage fri contained double‐stranded DNA. The resistance to high concentrations of either chloroform or ether showed that its lipid content was negligible. Heat lability was demonstrated by inactivation of a phage fri population within 10 min at 60°C and within 5 min at 70°C. It tolerated pH levels of 3.0–8.0 and exhibited greater stability in the acid region than did its host strain. The latent and rise periods were both 75 min, and the average burst size 200 pfu/cell. Sensitivity was limited to the Lact. plantarum strain of only one manufacturer of the commercial meat starters investigated.
The shelf life of vacuum-packed luncheon meats during refrigerated storage was not related to "total" counts since the only organisms that multiplied in this environment were lactic acid bacteria, which formed only a small proportion of the initial population.Bacterial growth curves obtained from several Canadian products were remarkably similar, but the spoilage patterns differed. For example, wiener spoilage was a function of bacterial growth while bologna spoiled from the accumulation of bacterial end products. After 15 weeks at 5 °C, the meats contained 0.6 to 0.8% lactic acid and the pH of comminuted meats dropped below 5.0. Cooked ham contained much less carbohydrate than comminuted meats, and the pH remained above 6.0. Under these conditions, ham is susceptible to putrefaction although this was not observed during this study.It was found that cooking can eliminate all lactic acid bacteria present in the raw meats but the products become recontaminated during slicing and packaging. The cleaning and sanitizing procedure used by the Company that cooperated in this study was efficient, but it was recommended that the packaging room be cleaned more often, and that a selective medium for lactic acid bacteria be used in sanitation surveys.
Four unprocessed Indian spices sampled at the point of export were shown to be highly contaminated with bacteria. Bacillus cereus was detected in more samples of these spices than any other spore-forming aerobe.
Black peppercorns supported the growth of Aspergillus parasiticus (flavus) NRRL 3145. Incubation at 28 C and RH of 85% for 30 days resulted in profuse conidial production on the reticulate ridges of the peppercorns. An SEM study of these ridges showed that they were cortical eruptions, and the particulate matter present favored mycelial establishment. Hyphal anastamoses were commonly observed. Following this incubation the inoculated peppercorns were stored in the dark at room temperature and ambient humidity for 15 days. Aflatoxin was detected on minicolumn. Aflatoxin B1 was produced at levels of 60 micrograms/kg with traces of aflatoxin B2, G1 and G2. Quantitative estimation was based on a visual comparison with standards by thin-layer chromatography.
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