Microbial Risk Assessment of Industrial Ice Cream Marketed in Italy

Psychrotrophic Bacteria Equipped with Virulence and Colonization Traits Populate the Ice Cream Manufacturing Environment

Several microbial taxa have been associated with food processing facilities, and they might resist by attaching on tools and equipment even after sanitation procedures, producing biofilms that adhere to the surfaces and might embed other microorganisms, including spoilers and pathogens. There is increasing evidence that these communities can be transferred to the final product. To explore the microbial contamination routes in a facility producing ice creams, we collected foods and environmental swabs from industrial surfaces of equipment and tools and performed taxonomic and functional analyses of the microbial DNA extracted from the environmental samples. Our results suggest that complex communities dominated by psychrotrophic bacteria (e.g., Pseudomonas and Acinetobacter spp.) inhabit the food processing environment, and we demonstrate that these communities might be transferred from the surfaces to the products. Functional analysis performed on environmental samples highlighted the presence of several genes linked to antimicrobial resistance and adherence on abiotic surfaces; such genes were more abundant on food contact (FC) than on other surfaces. Metagenome-assembled genomes (MAGs) of Pseudomonas stutzeri showed genes linked with biofilm formation and motility, which are surely linked to colonizing capabilities in the processing lines. The study highlights clear potential advantages of applying microbiome mapping in the food industry for source tracking of microbial contamination and for planning appropriate ad hoc sanitization strategies. IMPORTANCE Several microbial species might permanently establish in food processing facilities, thus contributing to food loss. In fact, food contact surfaces might transfer microorganisms to intermediates and products, potentially representing a hazard to human health. In this work, we provide evidence of the existence of complex microbial communities overcoming sanitation in an ice cream-producing facility. These communities harbored several genes that could potentially lead to attachment to surfaces and antimicrobial resistance. Also, prediction of routes of contamination showed that several potential spoilage taxa might end up in the final product. Importantly, in this work, we show that mapping the environmental microbiome is a high-resolution technique that might help food business operators ensure food quality and safety through detection of potentially hazardous microorganisms.

Nutritional, Physicochemical, Microstructural, Rheological, and Organoleptical Characteristics of Ice Cream Incorporating Adansonia digitata Pulp Flour

Ice cream's appeal is unrivaled. Nonmilk and milk ingredients in ice cream formulas affect their nutritional value, structure, and organoleptical qualities. Seeking novel dietary ingredients instead of artificial flavoring compounds is vital for improving ice cream taste preference, adding antioxidants, and increasing nutritional value. The current study examines the feasibility of manufacturing a new flavored ice cream with excellent dietary value using Adansonia digitata L. (Baobab) fruit pulp (ADFP). The prepared ice cream's physicochemical and microbiological quality, and rheological, microstructural, and organoleptic properties were investigated. Using ADFP instead of skim milk powder with a partial or complete replacement, five ice cream samples were produced and marked as IB-0, IB-25, IB-50, IB-75, and IB-100. Chemical characteristics were not noticeably impacted except protein and ash, which considerably decreased with increasing ADFP levels. Increasing ADFP in the samples increased titratable acidity and reduced pH. All ice cream samples were microbiologically acceptable with no pathogenic bacteria. By increasing ADFP in the samples, the daily values (%DV) of sodium, potassium, and magnesium were not considerably affected. Calcium reduced from 14.91% in IB-0 to 7.75% in IB-100. All microelements found in the study rose considerably as ADFP increased. Increasing ADFP levels significantly boosted antioxidant levels. The IB-100 sample had the highest total phenolic content (149.29 mg GAE 100 g^-1), antioxidant activity (98.12 µmol of TE 100 g^-1), total flavonoids (5.96 mg QE 100 g^-1), and total flavanols (4.01 mg QE 100 g^-1). The inclusion of ADFP had a beneficial effect on the color of the samples. It did not negatively affect the ice cream's organoleptic acceptability as determined by organoleptic, rheological, and microstructural examinations. Interestingly, when skim milk powder was replaced with 50% and 75%, the hardness, viscosity, and aqueous phase separation were significantly improved. In conclusion, ADPF improves the nutritional value of ice cream and can be used as a natural coloring ingredient without affecting microstructural and rheological properties.

Assessment of Antimicrobial Efficiency of Pistacia lentiscus and Fortunella margarita Essential Oils against Spoilage and Pathogenic Microbes in Ice Cream and Fruit Juices

Nowadays, the use of antimicrobial natural agents as alternative food preservatives represents an intriguing case. The purpose of this study was to investigate possible antimicrobial activity of Pistacia lentiscus and Fortunella margarita essential oils (EOs) and to evaluate their commercial potential in the food industry. The main constituents identified by GC/MS in Pistacia lentiscus EO were a-pinene (67.7%), myrcene (18.8%), and β-pinene (3.0%), whereas limonene (93.8%) and myrcene (2.7%) were the dominant compounds in Fortunella margarita EO. The antimicrobial properties were initially assayed and the minimum inhibitory, non-inhibitory, and minimum lethal concentration values against the Escherichiacoli, Listeria monocytogenes, Pseudomonas fragi, Aspergillus niger, and Saccharomyces cerevisiae were determined using a previously published model, combining absorbance measurements with the common dilution method and non-linear regression analysis to fit the data. Their efficiency was further validated in ice cream containing 0.2% (w/w) Pistacia lentiscus, 0.006% (w/w) Fortunella margarita EOs and 2% (w/w) aqueous residue of F. margarita EO deliberately inoculated with 4 logcfu/g Escherichiacoli, Listeria monocytogenes or Pseudomonas fragi, separately. Similarly, the activity of the oils was monitored in fruit juice (lemon, apple, and blackcurrant) containing 0.2% (w/w) Pistacia lentiscus, 0.006% (w/w) Fortunella margarita EOs and 2% (w/w) aqueous residue of F. margarita EO deliberately spiked with 100 spores/mL of Aspergillus niger or 4 logcfu/mL of Saccharomyces cerevisiae, separately. The results showed that microbial viable counts in the supplemented products ranged at significantly lower levels compared to the control samples during storage. Overall, the data indicated that both EOs constitute effective antimicrobial sources with many potent applications in the food industry.