Raffaella Branciari

Use of duplex polymerase chain reaction (duplex-PCR) technique to identify bovine and water buffalo milk used in making mozzarella cheese.

Molecular biology techniques have been used for species identification in food of animal origin in relatively recent years. A polymerase chain reaction (PCR) based method, the multiplex PCR, was recently applied to species identification in meat and meat products. It allows co-amplification of separate regions of a single gene or specific fragments, each typical of a different animal species in a single PCR reaction, using different pairs of primers in the same reaction mix. In the present paper, the duplex-PCR technique is proposed to identify bovine and water buffalo DNA in a single PCR assay in milk and mozzarella cheese (a typical Italian cheese, originally made from pure water buffalo milk). Because of its lower cost, undeclared bovine milk is added to water buffalo milk for making different kinds of mozzarella cheese. The results of this experiment indicate the applicability of this method, which showed an absolute specificity for the two species and a high sensitivity even down to low DNA concentrations (1 pg). In bovine and water buffalo mixtures of both milk and mozzarella cheese, the minimum concentration tested was 1% of bovine in water buffalo milk and water buffalo in bovine milk. The importance of the somatic cell content in raw milk is also discussed with special reference to the evaluation of mixtures (milk or cheese) of the two species.

Effect of genotype and rearing system on chicken behavior and muscle fiber characteristics

The effect of the organic production system and genotype on chicken behavior and muscle fiber characteristics was assessed. Three hundred day-old male chicks from slow-growing (Leghorn), medium-growing (Kabir), and fast-growing (Ross 208) genotypes were assigned to 2 different production systems: conventional, housing in an indoor pen (0.12 m(2)/bird); and organic, housing in an indoor pen (0.12 m(2)/bird) with access to a grass paddock (4 m(2)/bird). Behavioral observations were recorded from 73 to 80 d of age in the morning and afternoon. At 81 d of age, blood samples were collected to measure lactate dehydrogenase and creatine kinase, and 20 birds per strain and rearing system were slaughtered. Samples of pectoralis major, ileotibialis lateralis, and semimembranosus muscles were obtained for histological evaluations. Behavioral observations showed that genetic selection of animals for a better growth rate modified their behavior, reducing kinetic activity. Indeed, Leghorn birds were characterized by moving activities, whereas Kabir and Ross strains were discriminated on the basis of their lying, standing, and eating activities, and these activities were strongly associated with energy conservation, growth, and muscle fiber characteristics. Fiber characteristics and muscle enzyme functions were affected by rearing system only in animals adapted to the organic system. Interesting results relative to Leghorn chickens are the presence of alpha-Red fiber in breast muscle and the increased cross-sectional area of the ileotibialis lateralis muscle, which together with behavioral data could affirm that this genotype is the most adapted to the organic rearing system.

Seroprevalence and Risk Factors for Toxoplasma gondii Infection on Finishing Swine Reared in the Umbria Region, Central Italy

Toxoplasma gondii is a worldwide zoonotic protozoan parasite and pork is considered the major meat source of Toxoplasma infection in humans. To determine the prevalence of infection of Toxoplasma gondii in pigs reared in the Umbria Region (Central Italy), blood samples of 960 pigs from 10 different farms (96 for each farm) were randomly collected and tested for antibodies (IgG) against T. gondii using an IFA assay. Sera were screened at 1/16 titrr and the endpoint titre was determined. Farm management questionnaires were completed and used to develop descriptive statistics on the tested farms as well as to determine measures of association for risk factors for the presence of T. gondii‐seropositive pigs. A total of 155 seropositive pigs (16.14%) were identified; within herds prevalence ranged from 8.33 to 25%. The statistical analysis identified all‐in‐all‐out housing and cleaning method as risk factors for Toxoplasma infection.

Seroprevalence of Toxoplasma gondii in wild boars (Sus scrofa) from Central Italy

Wild and farmed game meat consumption has been highlighted as an emerging risk factor for Toxoplasma gondii infection in humans. In Central Italy wild boar is widely distributed and is also one of the most popular game species. The main goal of the present study was to estimate the seroprevalence of T. gondii antibodies through a serological survey conducted on 400 hunted wild boars (250 males and 150 females) during three subsequent hunting seasons (2009–2011), using an Immunofluorescence Antibody Assay. The animals were sorted by age, determined on the evaluation of the dental table; 101 were <1 year old, 175 from 1 to 3 years, and 124 > 3 years. Antibodies against T. gondii were detected in 56 (14%) serum samples with titers ranging from 40 to ≥160; a significant association (p < 0.05) was found between seropositivity and age, but not gender, hunting districts, or year of sampling.

Characterization of muscle fibre type and evaluation of the presence of giant fibres in two meat chicken hybrids

Giant fibres are muscle fibres characterized by peculiar traits when observed under a light microscope. They are usually rounded in shape, larger than normal fibres and stain darker when coloured with haematoxylin-eosin. Giant fibres were first studied by Cassens et al. (1969) and since then various authors have taken them into consideration, especially in swine where there seemed to be a connection between their presence and the PSE condition (Fazarinc et al., 2002; Severini and Loschi, 1997). This topic has recently also been considered in turkeys and chicken (Remignon et al., 2000; Mammoli et al., 2004). The aim of this study is to evaluate the muscle fibre distribution and the possible presence of giant fibres in two meat chicken hybrids characterized by different growth speeds.

Comparison Between Carcass Microbial Load Recovered by Swabbing Surfaces of Different Size and Using the Reference Excision Method

The Commission Decision of 8 June 2001 (Commission Decision 2001/471/EC), points out that the non-destructive carcass sampling method only removes a limited amount (often 20% or less) of the total flora present on carcass surfaces and suggests covering at least 100 cm2 per sampling site. Nevertheless, some authors have found similar results on sampling areas smaller than those suggested and when using the excision method (Gill and Jones, 2000). The aim of this study is to evaluate whether a reduction in the area sampled using the non-destructive method could influence the number of bacteria recovered from carcass surfaces in comparison with the excision method. This also takes into consideration the recommendation of the Italian Ministry of Health (Note of the Italian Ministry of Health, 2002) of a reduction in the sampling surface to 25 cm2 when sampling carcasses of 65 kg of live weight or less using the non-destructive method.

Prevalence of Campylobacter jejuni and Campylobacter coli in Chicken Hybrids with Different Growth Rates, Reared According to Conventional and “Free-Range” Production Methods

Miraglia D., Ranucci D., Branciari R., Cioffi A., Mammoli R., Cenci Goga B.T. and Avellini P., 2007. Prevalence of Campylobacter jejuni and Campylobacter coli in chicken hybrids with different growth rates, reared according to conventional and “Free-Range” production methods. Veterinary Research Communications, 31(Suppl. 1), 381–384

Effect of dietary treatment with olive oil by-product (olive cake) on physico-chemical, sensory and microbial characteristics of beef during storage

Several studies have demonstrated that the use of natural preservatives through animal diets could increase the shelf life of meat and meat products since many plant-derived substances show antioxidant and antimicrobial properties. The aim of this work was to study the effect of olive cake dietary supplementation on beef oxidative stability and antimicrobial activity during storage. Beef cattle were randomly divided into three homogeneous groups that were assigned to one of the three diets: a commercial unified based diet administered for 90 days until slaughter (CTR), CTR diet supplemented with 0.5% olive cake administered for 90 days until slaughter (OC1), and CTR diet supplemented with 0.5% olive cake and administered for 60 days followed by the administration of the CTR diet for 30 days until slaughter (OC2). Beefsteaks were overwrapped with oxygen-permeable packaging and analysed at four different storage times (zero, three, six and nine days). At the four sampling times considered from all of the samples, total viable count (TVC), Enterobacteriaceae counts, colour coordinates (CIE L*a*b* colour system), peroxide value (PV), thiobarbituric reactive substances (TBARs) determinations and descriptive sensory analyses were performed. No differences in TVC and Enterobacteriaceae count were detected among the groups over all of the sampling times considered. Differences were recorder among groups for PV, TBARS, colour and sensory analysis. The addition of olive cake in the animal diet had an effect on lipid oxidation reducing the level of PV, TBARS and retarding colour deterioration and the development of off odour in OC meat during storage.

Dietary integration with oregano (Origanum vulgare L.) essential oil improves growth rate and oxidative status in outdoor‐reared, but not indoor‐reared, pigs

The effects of a diet supplemented with oregano essential oil on performance, oxidative status, pork quality traits and sensorial properties were evaluated. In two studies, 72 pigs in indoor or outdoor conditions were assigned to either a control diet or an identical diet supplemented with 0.2% oregano essential oil. Pigs reared outdoor showed lower live weight, average daily gain and average gain:feed ratio compared to indoor pigs. The oregano supplementation improved the growth performance of the outdoor- but not the indoor-reared animals. The serum oxidative status was influenced by the diet. A higher oxidative stability was observed in the oregano-supplemented groups. As for the rearing conditions, the data suggest that after an initial adapting period, the free-range farming systems could be better tolerated by pigs. Meat derived from pigs reared outdoor showed higher pH and a* values. Lightness was influenced by both the diet and the rearing conditions. The control group reared indoor showed shear force values higher than both supplemented groups, while no differences were detected with the control group reared outdoor. In the consumer test performed under blind conditions, the oregano groups achieved higher consistency scores compared with the control. Under informed conditions, the meat derived from the oregano-supplemented pigs reared outdoor received the highest scores for consistency and overall liking regardless of the rearing system. The same result for the overall liking score was obtained in the expectation test. The data obtained showed that dietary oregano essential oil can be effective in reducing performance losses due to the outdoor-rearing system, increasing the oxidative status of the animal and oxidative stability of the meat, without modifying the meat quality traits and improving consumer perceptions of the meat quality.

Role of verocytotoxigenic Escherichia coli in the swine production chain

Shiga toxin-producing Escherichia coli (STEC) can cause severe clinical diseases in humans, such as haemorrhagic colitis (HC) and haemolytic-uremic syndrome (HUS). Although ruminants, primarily cattle, have been suggested as typical reservoirs of STEC, many food products of other origins, including pork products, have been confirmed as vehicles for STEC transmission. Only in rare cases, pork consumption is associated with severe clinical symptoms caused by high pathogenic STEC strains. However, in these outbreaks, it is unknown whether the contamination of food products occurs during swine processing or via cross-contamination from foodstuffs of different sources. In swine, STEC plays an important role in the pathogenesis of oedema disease. In particular a Shiga toxin subtype, named stx2e, it is considered as a key factor involved in the damage of swine endothelial cells. On the contrary, stx2e-producing Escherichia coli has rarely been isolated in humans, and usually only from asymptomatic carriers or from patients with mild symptoms, such as uncomplicated diarrhoea. In fact, the presence of gene stx2e, encoding for stx2e, has rarely been reported in STEC strains that cause HUS. Moreover, stx2e-producing STEC isolated from humans and pigs were found to differ in serogroup, their virulence profile and interaction with intestinal epithelial cells. Because of the limited epidemiologic data of STEC in swine and the increasing role of non-O157 STEC in human illnesses, the relationship between swine STEC and human disease needs to be further investigated.