Combined steam and ultrasound treatment of broilers at slaughter: a promising intervention to significantly reduce numbers of naturally occurring campylobacters on carcasses.

Steam or hot water decontamination treatment of broiler carcasses is hampered by process limitations due to prolonged treatment times and adverse changes to the epidermis. In this study, a combination of steam with ultrasound (SonoSteam®) was investigated on naturally contaminated broilers that were processed at conventional slaughter speeds of 8,500 birds per hour in a Danish broiler plant. Industrial-scale SonoSteam equipment was installed in the evisceration room, before the inside/outside carcass washer. The SonoSteam treatment was evaluated in two separate trials performed on two different dates. Numbers of naturally occurring Campylobacter spp. and TVC were determined from paired samples of skin excised from opposite sides of the breast of the same carcass, before and after treatments. Sampling was performed at two different points on the line: i) before and after the SonoSteam treatment and ii) before the SonoSteam treatment and after 80 min of air chilling. A total of 44 carcasses were examined in the two trials. Results from the first trial showed that the mean initial Campylobacter contamination level of 2.35 log10 CFU was significantly reduced (n=12, p<0.001) to 1.40 log10 CFU after treatment. A significant reduction (n=11, p<0.001) was also observed with samples analyzed before SonoSteam treatment (2.64 log10 CFU) and after air chilling (1.44 log10 CFU). In the second trial, significant reductions (n=10, p<0.05) were obtained for carcasses analyzed before (mean level of 2.23 log10 CFU) and after the treatment (mean level of 1.36 log10 CFU). Significant reductions (n=11, p<0.01) were also found for Campylobacter numbers analyzed before the SonoSteam treatment (2.02 log10 CFU) and after the air chilling treatment (1.37 log10 CFU). The effect of air chilling without SonoSteam treatment was determined using 12 carcasses pre- and postchill. Results showed insignificant reductions of 0.09 log10 from a mean initial level of 2.19 log10 CFU. Numbers of TVC before treatments ranged between 3.47 and 4.79 log10 CFU. In all cases, TVC was significantly (p<0.001, n=45 in each trial) reduced by approximately 0.7 log10 CFU. An authorized sensory panel at the Danish Veterinary and Food Administration concluded that broiler carcasses treated with SonoSteam were acceptable for purchase. These conclusions were based on organoleptic differences (smell, skin/meat consistency, texture and color) of treated vs. untreated carcasses. Results obtained from this study suggest that steam-ultrasound treatment of carcasses at broiler processing plants can significantly reduce numbers of Campylobacter on naturally contaminated broilers.

An evaluation of improvements in carcass hygiene through the use of anal plugging of pig carcasses prior to scalding and dehairing.

This study evaluated the effect of plugging the anuses of pork carcasses prior to scalding and dehairing on Enterobacteriaceae contamination on pork carcass surfaces. Results showed that Enterobacteriaceae counts around the anuses of unplugged carcasses increased by 1.15 log CFU/cm(2) after the scalding and dehairing process, while counts in the same sample area from plugged carcasses showed no significant change in Enterobacteriaceae numbers. The percentage of plugged carcasses with Enterobacteriaceae counts (measured around the anuses of carcasses) below the level of detection (<1 log) was 23.5%, whereas only 2.9% of unplugged carcasses were below this level. In the context of a multiple-hurdle approach where incremental reductions in microbiological counts may be seen as positive, anal plugging may have particular benefit.

Decontamination of poultry carcasses using steam or hot water in combination with rapid cooling, chilling or freezing of carcass surfaces.

The effects of the application of steam at atmospheric pressure for times up to 20 s on the numbers of inoculated Campylobacter jejuni and Escherichia coli on whole chicken carcasses were investigated in a pilot steam cabinet. Steam treatments reduced the numbers of C. jejuni AR6 by ca. 1.8, 2.6 and 3.3 log(10) cfu cm(-2) in 10, 12 and 20 s, respectively. Corresponding reductions in numbers of E. coli K12 were 1.7, 2.3 and 2.8 log(10) cfu cm(-2). However, such treatments caused the skin to shrink and change colour. The optimum treatment for maximum reductions of C. jejuni and E. coli, least skin shrinkage and change of colour was concluded to be <12 s. Further work was carried out to determine whether a modified air chilling system in combination with steam or hot water decontamination treatments could be used to reduce numbers of pathogens, particularly campylobacters, on the surface of poultry carcasses. Whole chicken carcasses inoculated with C. jejuni and E. coli were either not treated, treated with steam at atmospheric pressure for up to 10 s or treated with hot water at 80 degrees C for up to 20 s, then either chilled by crust freezing, chilled at 0 degrees C, or chilled at 15 degrees C, in a pilot chilling chamber. The optimum combination was treatment with water at 80 degrees C for 20 s followed by crust freezing, which reduced the numbers of C. jejuni and E. coli by ca. 2.9 and 3.2 log(10) cfu cm(-2), respectively, without extensive degradation of carcass appearance.

The production and microbiological status of skin-on sheep carcasses.

There is a demand by certain ethnic consumer groups in the United Kingdom for skin-on, singed carcasses, primarily from older sheep, but their production is illegal under current EU legislation. The aim of this study was to devise a protocol to produce carcasses having the desired 'smoked' colour and odour and an acceptable microbiology. A successful result could form the basis of a case to revise the legislation. Three key steps in the selected procedure were carcass singeing using specially designed gas burner equipment, pressure washing to clean the carcass and then evisceration. It was shown that a second heat application, termed 'toasting', if applied after evisceration, significantly (P<0.001) reduced Enterobacteriaceae and TVC counts on carcasses before chilling. Microbiological quality was also improved when toasting was the final step, following carcass splitting and inspection. Carcasses produced in this way had significantly (P<0.001) lower Enterobacteriaceae and TVC counts before chilling than conventionally dressed sheep carcasses produced in the same abattoir.