Single Carcass Research Articles

Factors Affecting the Persistence of Salmonella During the Processing of Poultry

Bacteria, including Salmonella, have been shown to attach firmly to poultry skin and meat. Neither fimbriae, flagella, nor electrostatic attraction seem to play a significant role in the mechanism of attachment. Bacterial cells (95%) were shown to be initially entrapped in a water film on the skin, then to migrate to the skin with prolonged immersion in a bacterial cell suspension. Using electron microscopy it was shown that bacteria appear to be entrapped in ridges and crevices which become more pronounced in the skin and muscle following water immersion. This may make bacteria on carcasses inaccessible to bactericides. It was shown that bacteria are firmly attached to poultry skin before broilers arrive at the plant and that high numbers are still recovered after 40 consecutive whole carcass rinses of a single carcass. It was further shown that Salmonella are not always recovered in the first whole carcass rinse and that this method of sampling could result in false negative reports for Salmonella incidence.

Relationships between organochlorine concentrations in liver and muscle of otters

The European otter (Lutra lutra) is now threatened or endangered over much of its European range. The decline, which has taken place mainly during the past three decades, has been attributed to the toxic effects of organochlorine residues, with emphasis being placed on dieldrin or PCBs. Few otters were analyzed for organochlorines during the main period of decline but there is not considerable interest in the species. Experiments with ranch mink (Mustela vison) have shown that reproductive failure occurs when PCB concentrations in thigh muscle approach 50 mg kg{sup {minus}1} lipid. Because otters are closely related and have similar habits this value is becoming widely used to interpret the potential significance of PCB concentrations determined in otters. Furthermore, although the mink data refer to concentrations in muscle, interpretations of concentrations in otters have frequently been based on analyses of livers. Because of the diverse sources of material in Europe, only limited tissues may be made available for analysis, while costs may also prohibit the analysis of several tissues from a single carcass. The relationship between concentrations of organochlorines in muscle and liver tissues in otters has not been determined. This is the purpose of the present communication.

Incidence and Recovery of Salmonellae and Other Bacteria from Commercially Processed Poultry Carcasses at Selected Pre- and Post-Evisceration Steps

This study was undertaken to determine whether bacteria are already attached to poultry skin when birds arrive at the processing plant. Multiple rinses were performed on breast skin and whole carcasses taken from five processing points in a commercial plant: Before scalding, after scalding, after picking, after the final washer, and from the exit end of the chiller. Aerobic bacteria and Enterobacteriaceae were recovered from carcasses in up to 40 consecutive whole carcass rinses with a difference of only about one log for Enterobacteriaceae, and 1 to 2 logs for aerobes from the first to the last rinse of carcasses taken from the beginning and the end of the processing line. Data from rinses prior to scalding indicated that bacteria were firmly attached to poultry carcasses when they first arrived in the plant. Not all bacteria were removed during processing; however, there were fewer aerobes and Enterobacteriaceae at progressive sampling points. Attached salmonellae were not always recovered in the first whole carcass rinse, but were sometimes recovered in 3rd, 5th, and 10th rinses. These data show that a single whole carcass rinse can result in false negative test results for salmonellae. Because of the small number of positive samples in this study, the probability of recovering salmonellae with a single whole carcass rinse could not be estimated accurately.

Current Methods of On-Line Carcass Evaluation

Most on-line systems of evaluation record carcass weight and classify carcasses post-slaughter for species, age, sex and fat cover. Conformation may be included, and more advanced systems estimate yield of salable meat or lean that then can be used as a basis for producer payment. Whereas grading/classification is mainly subjective for beef and sheep carcasses, the pig industry is the most advanced in moving to objective systems with fat cover, and in some cases muscle depth, measured objectively and used to estimate meat yield. Inexpensive, objective methods are needed for measuring the fat and meat content of beef and sheep carcasses at slaughter speed, provided that a method can be found that has an accuracy equal to or better than current subjective methods. Systems are being developed for deer and goat carcass on-line evaluation. Given that meat hygiene and inspection systems cover aspects of meat quality different from those covered in grading systems, but relate to the production of a satisfactory end-product, greater integration of these separate systems into a single on-line carcass evaluation system deserves consideration.

Comparison of Sampling Methods and Implications for Bacterial Decontamination of Poultry Carcasses by Rinsing

This study showed that the whole carcass rinse and the stomaching or blending of excised skin techniques for sampling broilers, as commonly used, result in the isolation of comparable numbers of aerobes and Enterobacteriaceae. However, these data also show that all three methods recover only a very small percentage of the total bacteria present on broiler carcasses. Large numbers of bacteria were still recovered from the fortieth rinse of a single carcass, indicating that increased rinsing after bacteria become firmly attached to the carcass will only result in a slight reduction of the total bacterial load present, and will not result in a meaningful improvement in bacterial quality of the carcass.

OBSERVATIONS ON THE DEVELOPMENT OF COPIDOSOMA GELECHIÆ

1. Copidosoma gelechiae, which is a parasite in the Solidago Gall Moth, Gnorimoschema salinaris, has but one generation a year.2. The egg of this parasite is probably laid during the month of May.3. The type of development in Copidosoma is polyembryonic. The number of individuals average about 191 per brood.4. In the youngest stages secured the process of division of the egg into embryonic primordia is already in progress. The young polygerm consists of two distinct regions: (1) An outer zone, or nucleated membrane, containing the free polar nuclei; (2) a central region, containing the true embryonic nuclei.5. The embryonic nuclei segregate into groups, which become surrounded by a dense layer of granular protoplasm and form the primordia of the multiple embryos.6. During early growth the polygerm elongates into a cylindrical-shaped structure, which becomes broken up into several spherical, primary masses by the formation of constrictions in the nucleated membrane. Each primary mass receives several of the primitive embryos.7. The primary masses become broken up into secondary masses by further constrictions of the nucleated membrane. At the end of these divisions, each embryo is separated from the others and is surrounded by an inner and an outer involucre—the former derived from the granular protoplasm and the latter from a portion of the nucleated membrane.8. The interstices between these masses become filled with an inter-embryonal substance derived from at least three sources: elements from the nucleated membrane, leucocytes, and cells from the adipose tissue, which usually is laid down in the form of a thick layer on the outer surface of the polygerm. The entire structure thus becomes a complex, which may be called the polygermal mass.9. The dissociation of the inter-embryonal substance sets the larvæ free in the body cavity of the host. This occurs during the last week of July.10. Abortive or degenerating embryos are found throughout the entire period covered by the polygerm and free larval stages.11. The free larvæ destroy the entire contents of the caterpillar, except the chitinous parts of the trachae, and leave only the superficial layer of chitin of the body wall intact. The detritus left in the larval chitin hardens to form thin-walled, oval chambers in which the larvæ lie and undergo pupation The superficial layer of chitin also hardens, and the larval skin thus becomes transformed into the typical mummified carcass, filled with the parasitic pupae.13. Pupation takes place during the first ten days of August and lasts about a month.14. The number of adult parasites emerging from the carcasses varies from 25 to 395. There is a preponderance of females, about 55 per cent. of all broods being females. Furthermore, the average number of females emerging from a single carcass is 198 as compared with 175 for the males. Ten mixed broods of males and females have been obtained. Some of these have doubtless arisen from two or more eggs; but it is suggested that such broods may also arise from a single fertilized egg, by a process of disjunction of the sex chromosomes during the early cleavage stages.