Counting, microbial bacteria

Depending on the counts of bacteria and fungi made at increasing incubation times of the test units, the microbial status was assessed as increasing, declining or non-viable,... 

Packaging materials which have a smooth, impervious surface, free fi cm crevices or interstices, such as cellulose acetate, polyethylene, polypropylene, poly vinylchloride, and metal foils and laminates, all have a low surface microbial count. Cardboard and paperboard, unless treated, carry mould spores of Cladosporium spp., Aspergillus spp. md Penicillium spp. and bacteria such 2 Bacillus spp. sn.dMicrococcus spp. 

There are large numbers of gram-positive and gram-negative bacteria and fungi in various materials associated with cotton. Table II lists studies giving an overall picture of the microbial (viable organism counts) content of various cotton dusts. A few pertinent references are summarized. 

Samples were taken three times throughout the year (summer, winter, and spring, 1973-1974), and microbial species present (bacteria, actlnomycetes and fungi) were determined. Bacterial counts were higher for soils with greater moisture content, but the herbicide, in any concentration, had no significant effect on the microflora. 

Bacterial Growth and Histamine Formation. The quantitative relationship between histamine formation and the microbial flora in skipjack tuna at 38 C is shown in Figure 3. At intervals during incubation samples were removed from the second section and assayed for histamine content and bacterial numbers. After 24 h the anaerobic bacterial count was 3.5 x 10 per g, and the histamine content was 297 mg per 100 g. Anaerobic counts were used to measure the microbial population because over 92% of the bacteria found in decomposed skipjack tuna were obligate or facultative anaerobes (Table I). 

Count the number of microbial colonies on each plate. The microbial estimates are reported per contact plate or per swab. Examine the types of colonies and submit the representative colonies for identification. Mold does not carry special status relative to bacteria. Any significant shifts in type or number require action — regardless of mold vs. bacteria. 

Usually, total aerobic bacteria, molds, and yeasts are counted by using a standard plate count in order to test the microbial limits. The microbial limit test may be customized by performing a screening for the occurrence of Staphylococcus aureus, Pseudomonas aeruginosa, Pseudomonas cepacia, Escherichia coli, and Salmonella sp. [56],... 

Microbial limits—sets limits of total bacteria and mold count. 

---