Marina Pasquini

Insight into the proximate composition and microbial diversity of edible insects marketed in the European Union

In recent years, the idea of exploiting edible insects for their industrial production has attracted the attention of media, research institutions and food industry operators, because of the numerous positive factors associated with this food source. Notwithstanding, insects are still underutilized in Western countries. Moreover, edible insects are carriers of natural microorganisms; hence, safety issues may arise from their industrial production. This study was aimed at providing insight into the proximate composition, with a focus in the fatty acid and amino acid composition, and microbial diversity of some processed edible insects marketed in the European Union. A high content of protein and fat was seen, with values ranging from 59.46 to 46.78 and 35.32 to 15.18%, respectively, with nutritionally valuable characteristics in both the lipid fractions and amino acid profiles. Furthermore, a great variation in microbial counts was seen. Both commensal and potential pathogenic microorganisms ascribed to the genera Pediococcus, Weissella, Streptomyces, Acinetobacter, Agrococcus, Arthrobacter, Naxibacter, Planomicrobium, Rufibacter, Bacillus, Clostridium, Vibrio, Desulfovibrio, Loktanella, Escherichia, Tetrapisispora, Aspergillus, Eurotium, Debaryomyces, and Wallemia, were identified by PCR-DGGE. The high diversity in the chemical composition and microbial profile of the marketed edible insects analyzed suggest a role of both the rearing and processing procedures on these variables. The results overall collected encourage the exploitation of edible insects as a valuable large-scale, animal-based commodity.

Getting insight into the prevalence of antibiotic resistance genes in specimens of marketed edible insects.

This study was aimed at investigating the occurrence of 11 transferable antibiotic resistance (AR) genes [erm(A), erm(B), erm(C), vanA, vanB, tet(M), tet(O), tet(S), tet(K), mecA, blaZ] in 11 species of marketed edible insects (small crickets powder, small crickets, locusts, mealworm larvae, giant waterbugs, black ants, winged termite alates, rhino beetles, mole crickets, silkworm pupae, and black scorpions) in order to provide a first baseline for risk assessment. Among the AR genes under study, tet(K) occurred with the highest frequency, followed by erm(B), tet(S) and blaZ. A high variability was seen among the samples, in terms of occurrence of different AR determinants. Cluster Analysis and Principal Coordinates Analysis allowed the 11 samples to be grouped in two main clusters, one including all but one samples produced in Thailand and the other including those produced in the Netherlands.

Trends in the microbial contamination of bovine, ovine and swine carcasses in three small-scale abattoirs in central Italy: A four-year monitoring

The microbial contamination of animal carcasses with respect to the limits established by Regulation (EC) No. 2073/2005 was investigated. Bovine, ovine, and swine carcasses (n=536 samples) from three small-scale abattoirs were sampled using abrasive sponges and tested for aerobic colony counts (ACC) and Enterobacteriaceae in the period 2010-2013. Mean ACC values reached 1.96 log cfu/cm(2) on bovine carcasses and 2.27 log cfu/cm(2) on both swine and ovine carcasses; Enterobacteriaceae counts of 0.01, 0.20 and 0.27 log cfu/cm(2) were found for bovine, swine and ovine carcasses, respectively. Abattoir 1 showed the highest values of ACC; no differences among abattoirs were highlighted for Enterobacteriaceae. Compared with swine and ovine carcasses, bovine carcasses showed significantly lower means for both ACC and Enterobacteriaceae. The data collected indicated that the management of the three abattoirs met high quality standards, thereby proving that it is feasible to achieve good microbiological quality in abattoirs when adequate Good Hygiene Practices are applied.

Evaluation of the digestibility of Lathyrus sativus in growing pigs

Abstract The EU ban on meals of animal origin and the rejection by some States, including Italy, of genetically modified organisms (e.g. soybean), have resulted in the need for novel protein sources. The present study was undertaken to evaluate the digestibility of rations where soybean was partially replaced with Lathyrus sativus L. Twelve hybrid growing pigs were fed three diets formulated to be isoenergetic and isoproteic according to a Latin square design, each for 22 days. In the two experimental diets soybean was replaced by 10% or 20% L. sativus. Subjects were about 78 kg live weight at baseline. After 10 days of adaptation to each diet, faeces samples were collected from the rectum at the same time of day for 3 days. At the end of the administration of each diet, animals were weighed and blood was collected to determine some protein metabolism parameters. Feed and faeces were analysed for nutrients and AIA in order to calculate the coefficients of digestible utilisation of nutrients. Results were analysed by ANOVA using JMP (SAS system). The growth performance data (ADG and FCR) did not demonstrate differences attributable to the substitution of soybean with L. sativus. The coefficients of digestible utilisation indicate that soybean can be replaced with this legume seed. Low plasma urea in animals receiving 20% L. sativus confirmed the good metabolic efficiency of protein.

Transferable Antibiotic Resistances in Marketed Edible Grasshoppers (Locusta migratoria migratorioides)

Grasshoppers are the most commonly eaten insects by humans worldwide, as they are rich in proteins and micronutrients. This study aimed to assess the occurrence of transferable antibiotic resistance genes in commercialized edible grasshoppers. To this end, the prevalence of 12 selected genes [aac(6)-Ie aph(2″)-Ia, blaZ, erm(A), erm(B), erm(C), mecA, tet(M), tet(O), tet(S), tet(K), vanA, vanB] coding for resistance to antibiotics conventionally used in clinical practice was determined. The majority of samples were positive for tet(M) (70.0%), tet(K) (83.3%) and blaZ (83.3%). A low percentage of samples were positive for erm(B) (16.7%), erm(C) (26.7%), and aac(6)-Ie aph(2″)-Ia (13.3%), whereas no samples were positive for erm(A), vanA, vanB, tet(O), and mecA. Cluster analysis identified 4 main clusters, allowing a separation of samples on the basis of their country of origin.

Influence of diet and rearing system on heavy pig performance, carcass and meat quality

Abstract Identifying alternative dietary protein sources and new types of outdoor rearing techniques that enhance animal welfare, thus optimising costs and production performance, are among the main objectives of nutritionists and breeders. The aim of this study was to compare two types of rations where pea and potato concentrate completely substituted soybean in intensively and extensively bred swine. Forty Large White × Duroc piglets weighing about 40 kg were divided into 4 groups of 10 sex- and weight-matched individuals: Indoor rearing + Control diet, Indoor rearing + Experimental diet, Outdoor rearing + Control diet, Outdoor rearing + Experimental diet. Different diets were formulated for the growing phase (40-100 kg) and the fattening period (100-slaughter); pigs, weighed individually every 40 days to estimate the average daily gain and feed conversion rate, were slaughtered when they reached the weight for Italian ham production. The following measurements were obtained: carcass weight, slaughtered yield, weight of lean cuts, pH 45 minutes and 24 hours post mortem. 40 semimembranosus muscle samples were analysed for colour parameters (L*, a* and b*), moisture, fat, protein and ash while the energy values were calculated. Semimembranosus intramuscular fat and ham backfat were analysed for fatty acid profile. Statistical analysis of performances data was conducted using design with repeated measures and the slaughterhouse, meat and fat composition data were subjected to ANOVA. The results show that soybean can be completely substituted with other protein crops. Rearing and slaughterhouse performances were not affected by the diet, whereas significant differences emerged with the rearing system. Diet composition significantly affected lean meat proportion (50.0 vs 48.2) and fat thickness of 3/4 Thoracic Vertebra (25.3 vs 28.3 mm), while the rearing system significantly affected all carcass quality measures. Some parameters were better in outdoorthan indoor-subjects. Meat colour was also significantly influenced by the rearing effect, being less light and yellow in the former subjects (L* 49.9 vs 37.3; b* 3.7 vs 2.3). Chemical analysis demonstrated that the meat of outdoor-reared subjects was leaner (1.96% vs 1.38% fat) and had a lower water content (72.8% vs 71.8%). The complete replacement of soybean is thus compatible with a strong characterization and an enhancement of the value of swine products. In addition, the rearing system can result in distinctive quality features, such as ham colour and fat content, allowing products from outdoor rearing to be clearly recognized from those obtained from intensive rearing.

The bacterial biota of laboratory-reared edible mealworms (Tenebrio molitor L.): From feed to frass

Tenebrio molitor represents one of the most popular species used for the large-scale conversion of plant biomass into protein and is characterized by high nutritional value. In the present laboratory study, the bacterial biota characterizing a pilot production chain of fresh T. molitor larvae was investigated. To this end, different batches of fresh mealworm larvae, their feeding substrate (wheatmeal) and frass were analyzed by viable microbial counts, PCR-DGGE and Illumina sequencing. Moreover, the occurrence of Coxiella burnetii, Pseudomonas aeruginosa and Shiga toxin-producing E. coli (STEC) was assessed through qualitative real-time PCR assays. Microbial viable counts highlighted low microbial contamination of the wheatmeal, whereas larvae and frass were characterized by high loads of Enterobacteriaceae, lactic acid bacteria, and several species of mesophilic aerobes. Spore-forming bacteria were detected to a lesser extent in all the samples. The combined molecular approach used to profile the microbiota confirmed the low microbial contamination of wheatmeal and allowed the detection of Enterobacter spp., Erwinia spp., Enterococcus spp. and Lactococcus spp. as dominant genera in both larvae and frass. Moreover, Klebsiella spp., Pantoea spp., and Xenorhabdus spp. were found to be in the minority. Entomoplasmatales (including Spiroplasma spp.) constituted a major fraction of the microbiota of one batch of larvae. From the real-time PCR assays, no sample was positive for either C. burnetii or STEC, whereas P. aeruginosa was detected in one sample of frass. Based on the overall results, two sources of microbial contamination were hypothesized, namely feeding with wheatmeal and vertical transmission of microorganisms from mother to offspring. Since mealworms are expected to be eaten as a whole, the overall outcomes collected in this laboratory study discourage the consumption of fresh mealworm larvae. Moreover, microbial loads and the absence of potential pathogens known to be associated with this insect species should be carefully assessed in order to reduce the minimum risk for consumers, by identifying the most opportune processing methods (e.g., boiling, frying, drying, etc.).

Prevalence and risk factors for thermotolerant species of Campylobacter in poultry meat at retail in Europe

ABSTRACT The thermotolerant species Campylobacter jejuni, Campylobacter coli, Campylobacter lari and Campylobacter upsaliensis are the causative agents of the human illness called campylobacteriosis. This infection represents a threat for the health of consumers in Europe. It is well known that poultry meat is an important food vehicle of Campylobacter infection. As emerged from the reported scientific literature published between 2006 and 2016, poultry meat sold at retail level in Europe represents an important source of the pathogen. The contamination level of poultry meat sold at retail can vary depending on pre‐ and post‐harvest factors. Among the pre‐harvest measures, strict biosecurity practices must be guaranteed; moreover, among post‐harvest control measures scalding, chilling and removal of faecal residues can reduce the contamination level of Campylobacter. An additional issue is represented by increasing proportion of Campylobacter isolates resistant to tetracyclines, ciprofloxacin, and nalidixic acid, thus feeding a serious concern on the effectiveness of antibiotic treatment for human campylobacteriosis in a near future.

Occurrence of transferable antibiotic resistances in commercialized ready-to-eat mealworms (Tenebrio molitor L.)

The present study aimed to assess the occurrence of transferable determinants conferring resistance to tetracyclines, macrolide-lincosamide-streptogramin B, vancomycin, beta-lactams, and aminoglycosides in 40 samples of commercialized edible mealworms (Tenebrio molitor L.) purchased from European Union (EU) and non-EU producers. A high prevalence of tet(K) was observed in all of the samples assayed, with percentages of PCR-based positivity that ranged from 80% (samples from Thailand) to 100% (samples from the Netherlands, Belgium and France). For macrolides, erm(B) prevailed, being detected in 57.5% of the samples assayed, whereas erm(A) and erm(C) were detected with lower frequencies. Genes for resistance to vancomycin were only detected in samples produced in France and Belgium, with 90% and 10% of the samples being positive for vanA, respectively. Beta-lactamase genes were found with low occurrence, whereas the gene aac-aph, conferring high resistance to aminoglycosides, was found in 40% of the samples produced in the Netherlands and Belgium and 20% of the samples produced in Thailand. The results of Principal Coordinate Analysis and Principal Component Analysis depicted a clean separation of the samples collected from the four producers based on the distribution of the 12 AR determinants considered. Given the growing interest on the use of mealworms as a novel protein source, AR detection frequencies found in the present study suggest further investigation into the use of antibiotics during rearing of this insect species and more extensive studies focused on the factors that can affect the diffusion of transferable ARs in the production chain. Until such studies are completed, prudent use of antibiotics during rearing of edible insects is recommended.

The occurrence of spoilage yeasts in cream‐filled bakery products

BACKGROUNDnFilling creams can provide an adequate substrate for spoilage yeasts because some yeasts can tolerate the high osmotic stress in these products. To discover the source of spoilage of a cream-filled baked product, end products, raw materials, indoor air and work surfaces were subjected to microbiological and molecular analyses. The efficacy of disinfectants against spoilage yeasts was also assessed.nnnRESULTSnThe analyses on end products revealed the presence of the closest relatives to Zygosaccharomyces bailii with counts ranging from 1.40 to 4.72u2009logu2009cfuu2009g-1 . No spoilage yeasts were found in the indoor air and work surfaces. Polymerase chain reaction-denaturing gradient gel electrophoresis analysis, carried out directly on filling creams collected from unopened cans, showed the presence of bands ascribed to the closest relatives to Z.u2009bailii sensu lato, although with countsu2009<u20091u2009logu2009cfuu2009g-1 . Susceptibility testing of yeast isolates to disinfectants showed a significantly lower effect of 10% alkyl dimethyl benzyl ammonium chloride. Different responses of isolates to the tested disinfectants were seen.nnnCONCLUSIONnTo guarantee the quality of end products, reliable and sensitive methods must be used. Moreover, hygiene and the application of good manufacturing practices represent the most efficient way for the prevention and minimization of cross-contamination.