Isolation of Campylobacter jejuni from poultry carcases.

Campylobacter jejuni was isolated from 94% of chicken carcase rinses collected in a Queensland poultry abattoir. Direct plating resulted in the isolation of the organism from 84% of the rinses. A further 10% were found to contain C. jejuni by a procedure of selective enrichment and membrane filtration. Counts of C. jejuni on the carcases ranged from 0 to 1.1 x 10(5) organisms per carcase.

Salmonellae on posts, hand-rails and hands in a beef abattoir.

Counts of salmonellae were done by the most probable number technique on samples collected from the hands of abattoir workers as well as on samples from hand-rails and posts regularly touched by the workers. Salmonellae were isolated from the hands of 52% of the workers who handled the hide. They had the highest average counts with counts ranging from 0 to greater than 3663 salmonellae. The remaining workers on the slaughter floor and those in the boning room had generally lower counts with contamination rates of 28% and 45% respectively. Only 3 of the 100 samples collected from the hand-rails and posts contained salmonellae. The average count was 0.11 per 100 cm2.

The role of equipment having accidental or indirect contact with the carcase in the spread of Salmonella in an abattoir.

Counts of salmonellae were performed by the most probable number technique on steels, aprons, scabbards and on structures within the abattoir with which carcases made accidental contact. Counts on steels ranged from 0-153 salmonellae per steel; aprons from 0-14 per 100 cm2; scabbards from 0-greater than 3667 per scabbard; and carcase bump points from 0-40 per 100 cm2. Contamination rates were highest for the equipment of workers whose job functions brought them in contact with the hide.

Microbiological quality of Queensland stockfeeds with special reference to salmonella.

One hundred Queensland stockfeeds were examined for their counts of total aerobic bacteria, coliforms, fungi and salmonellas. The total aerobic bacteria, coliform and fungal counts were significantly higher (P < 0.005) for mashes than for crumbles and pellets and salmonellas were isolated from significantly more (P < 0.005) mashes (64%) than pellets and crumbles (8%). Counts of less than 1 salmonella per 100 g were found in 36.4% of the 44 positive feeds. The remainder of the counts ranged from 1.2 per 100 g to greater than 147 salmonellas per 100 g feed.

The role of equipment that has direct contact with the carcase in the spread of Salmonella in a beef abattoir.

Counts of Salmonella were performed by the most probable number technique on 16 articles of abattoir equipment having direct contact with the carcase. Forty samples were collected from each article over 21 months. The contamination rate of these articles with salmonellae varied from nil % for a saw used to quarter the sides to 47.5% for stainless steel tables and hooks. Mesh gloves were also highly contaminated, salmonellae being isolated from 32.5% of gloves on the slaughter floor and 40% of those in the boning room. Salmonella counts ranged from 1.0 to 3,663 organisms per article. Mesh gloves, cutting boards and stainless steel tables were found to have counts that were at times greater than 1,000 salmonellae per article.

Bacteriological aspects of the disposal of manure from beef cattle.

Manure, collected from cattle housed in yards, was spread on experimental plots at the rate of 120 tonnes per hectare per annum. The manure was applied to 2 plots at 6-monthly intervals while a further 2 plots received monthly applications. Samples of manure soil, run-off and ground waters were examined for their counts of total aerobic bacteria, coliforms, faecal coliforms and for the presence of salmonellae. Comparison of the bacterial counts from samples from the test plots to those of the control plots showed that no change occurred in the levels of coliforms or faecal coliforms over the 3 years of manure application. One hundred and fifty-seven isolations of salmonella were made from the soil and water samples, but only 51 could be attributed to the manure. No difference was observed in the effects of different application frequencies.

Examination of stockfeeds for Salmonella.

Of 100 stockfeeds examined for Salmonella 45 were positive by pre-enrichment followed by selective enrichment of 10 x 25 g samples. Forty-three were positive by selective enrichment of pooled aliquots of the pre-enrichment broths from the 10 x 25 g samples. Aliquots of the pre-enrichment broths from the 10 x 25 g samples of 77 of the feeds were stored at 4 degrees C and retested after 6 days. One hundred and ten of these (770) subsamples were found to contain salmonellas initially, and 107 were found to contain salmonellas after storage for 6 days. The testing of feeds by the examination of multiple 25 g samples and pooled pre-enrichment broths is recommended. Aliquots of the pre-enrichment broths may be stored at 4 degrees C for 6 days and retested if an estimation of the numbers in the feed is required. Further pre-enrichment after cold storage is not required.

Bacterial penetration in floor and nest box eggs from meat and layer birds.

A method similar to that used by Board and Board (1967) was used to determine the numbers of eggs penetrated by bacteria on 3 poultry farms in south-east Queensland. Significant differences in the percentages of penetrated eggs between the eggs of layer birds (9.7%) and the eggs of meat birds (16.1%) and between nest eggs (10.5%) and floor eggs (15.3%) were detected. The distribution of the numbers of penetration points was similar for nest and floor eggs for both types of bird and was independent of shell surface area or thickness.

Secondary selective enrichment of salmonellae from naturally contaminated specimens by using a selective motility system.

A selective motility medium was used as a secondary selective enrichment medium to examine specimens naturally contaminated with salmonellae. The medium, incubated at 37 degrees C, was inoculated from either selenite brilliant green sulfa enrichment broth or Müller-Kauffman tetrathionate broth, both of which had been incubated at 42 degrees C. The use of the selective motility medium resulted in an increase in the number of positive specimens from 65 and 74% to 80 and 82%, when inoculated at 24 and 48 h, respectively, from tetrathionate broth. Tetrathionate broth, when used singly, was significantly better than selenite brilliant green sulfa broth, which detected 55% of positive specimens at both 24 and 48 h. The use of the selective motility medium of Harper and Shortridge (J. Hyg. 67: 181--186, 1969) for the further examination of specimens culturally negative on primary selective enrichment is advocated.

THE ROLE OF EQUIPMENT THAT HAS DIRECT CONTACT WITH THE CARCASE IN THE SPREAD OF SALMONELLA IN A BEEF ABATTOIR.

Counts of Salmonella were performed by the most probable number technique on 16 articles of abattoir equipment having direct contact with the carcase. Forty samples were collected from each article over 21 months. The contamination rate of these articles with salmonellae varied from nil % for a saw used to quarter the sides to 47.5% for stainless steel tables and hooks. Mesh gloves were also highly contaminated, salmonellae being isolated from 32.5% of gloves on the slaughter floor and 40% of those in the boning room. Salmonella counts ranged from 1.0 to 3,663 organisms per article. Mesh gloves, cutting boards and stainless steel tables were found to have counts that were at times of greater than 1,000 salmonellae per article.