Bacterial Inhibitors Formed During the Adventitious Growth of Micro‐organisms in Chicken Liver and Pig Kidney

Abstract

Inhibitory activity (detected by Bacillus cereus var. mycoides), identical with that encountered in survey samples, was induced in homogenized fresh chicken liver or pig kidney samples by incubating at 30°C. relative potency of each of three active components as detected by t.l.c./bio‐autography of extracts of freeze‐dried material was ascertained. Three strains of Streptococcus faecalis and a Lactobacillus sp. were responsible for production of the inhibitory activity, which was not produced by any of these organisms in synthetic liquid media.

Antibiotic residues in meat in the United Kingdom; an assessment of specific tests to detect and identify antibiotic residues

“…False positive results occurred in response to various microbial processes. Firstly, meat discs applied to test plates could already contain natural inhibitors which were presumably derived from earlier bacterial activity within the original sample (Smither, 1978). In support of this theory it was found that these samples were invariably heavily contaminated with bacteria, and that extracts of freezedried sample material were inhibitory to test bacteria.…”

“…The sensitivity of all test plates was monitored by applying 6 mm diameter filter paper discs impregnated with sodium benzylpenicillin (0-01 i.u./disc), streptomycin (0.5 5g/disc) or sulphadimidine (0 5,ug/disc) (Mast Laboratories, Liverpool) which gave annular zones of inhibition of a specified minimum size, that is > 6-8 mm extending from the discs. Electrophoresis and t.l.c./bio-autography Positive FPT samples from both UK-produced and imported meat were examined further at LGC by high voltage electrophoresis (Smither & Vaughan, 1978) to identify antibiotics, and t.l.c./bio-autography (Smither, 1978) to establish the presence of naturally produced inhibitors. The exudates obtained from thawed tissues as well as extracts from freeze-dried material were used for electrophoresis.…”

“…Thirty-four (0.63 %) of the 5442 UK-produced meat samples (Table 2) failed the FPT on initial screening, 27 (79.4 %) of the failures being derived from pig meat. On retesting the FPT failures at LGC, electrophoresis and t.l.c./bioautography revealed that 20 failures were actually negative and that 12 other failures were caused by naturally produced inhibitors similar to or identical to those described by Smither (1978), and could therefore be considered as falsely positive with respect to the test. Only two failures in the FPT were caused by the presence of antibiotics.…”

“…Published information concerning antibiotic residues in meat in the United Kingdom has been limited as far as we are aware to data on certain offals mentioned by Smither (1978). During the period 1977 to 1979 further investigations were conducted, in which meat produced in the United Kingdom was initially tested at the Veterinary Investigation Centre, Reading (VICR), whilst meat and offal imported into the United Kingdom was tested at the Laboratory of the Government Chemist, London (LGC).…”

Antibiotics, Animals, Meat and Milk

“…of bactericidal activity (13). Other inhibitory substances have also been recognised and, in particular, lysozyme and similar substances have been found in pig kidneys (18). Lysozyme is released when tissues are thawed from the deep-frozen state and so this particular inhibitory substance could be avoided if fresh, non-frozen, tissues were used for assay.…”