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The effects of hydrostatic (HHP) and dynamic (HPH) high-pressure treatments on the activity of pectin methylesterase (PME) and polyphenol oxidase (PPO) as well as the physicochemical quality attributes of 'Ataulfo' mango nectar were assessed. HHP reduced PME relative activity by 28% at 100 MPa for 5 min but increased PPO activity almost five-fold. Contrarily, HPH did not affect PME activity, but PPO was effectively reduced to 10% of residual activity at 300 MPa and at three passes. Color parameters (CIEL*a*b*), °hue, and chroma were differently affected by each type of high-pressure processing technology. The viscosity and fluid behavior were not affected by HHP, however, HPH changed the apparent viscosity at low dynamic pressure levels (100 MPa with one and three passes). The viscosity decreased at high shear rates in nectar samples, showing a shear-thinning effect. The results highlight how different effects can be achieved with each high-pressure technology; thus, selecting the most appropriate system for processing and preserving liquid foods like fruit beverages is recommended.

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INTRODUCTION: Aflatoxins are secondary metabolites produced mainly by the molds Aspergillus flavus, A. parasiticus and A. nomius, and they contaminate cereals, dry fruits, oilseeds and spices. Aflatoxins have harmful effects in animals and humans, inducing vomiting, diarrhea, hepatitis, cirrhosis, immunosuppression, miscarriages, mutagenic and teratogenic effects, resulting in different cancers. Popcorn (Zea mays everta) is a cereal susceptible to aflatoxin contamination, and there are no reports about the risk of its consumption. PURPOSE: A study on the incidence and consumption of aflatoxins in popcorn marketed in the city of Veracruz, Mexico was conducted and evaluated to carry out a risk assessment for human health. METHODS: To obtain popcorn, a random sampling in 30 places was done. Frequency of consumption was obtained with informed consent of participants of 253 surveys that considered gender (56% women and 44% men), age (13 less than 18 years, 218 older than 18 years and 22 older than 60 years) and the average body weight, which was 65.5 kg for women and 72.7 kg for men. RESULTS: Aflatoxins were found in 47% of the 30 samples. The estimated daily consumption among women was 21 g of popcorn daily with 2.8 ng kg-1 body weight aflatoxin B1 (AFB1) and 18.29 ng kg-1 body weight total aflatoxins, and for men, the values were 3.0 ng kg-1 body weight AFB1, and 16.0 ng kg-1 body weight of total AF; 1 ng kg-1 body weight is recommended as the tolerance limit by the JECFA (2001). CONCLUSION: The highest liver cancer risk was detected in men population under 18 years of age, with 0.137 cases in 100,000 persons. The results show that 9.5% of the consumers of AFB1-contaminated popcorn are at risk, and 52.2% are at risk for total aflatoxin exposure. Popcorn is accessible to children with lower weight, increasing the risk.

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Aflatoxins (AFs) are toxic secondary metabolites of the fungi Aspergillus flavus, A. parasiticus and A. nomius. The fungi produce these AFs in cereals, oilseeds and spices. AFs have damaging effects on all organisms, including humans, and their symptoms can be classified as acute (vomiting, hemorrhage and death) or chronic (immunodepression, Reye syndrome, Kwashiorkor, teratogenesis, hepatitis, cirrhosis, and various cancers). Basic AFs (AFB1, AFB2, AFG1, and AFG2) are metabolized in the liver or by microbes that produce hydroxylated metabolites (AFM1, AFM2, and AFP1) and aflatoxicol (AFL), soluble in water and easy to dispose. Thus, AFs can be excreted in fluids, such as milk. AFs are not destroyed in the process of making cheese. The purpose of this study was to identify and quantify the AFs present in 30 samples of industrialized Oaxaca-type cheese sold in Mexico City. The average concentrations of AFs detected in the 30 samples of industrialized cheese were as follows: AFB1 (0.1 µg kg-1) in 20% (6/30); a trace amount of AFB2 (0.01 < LOD) in only 3% (1/30); AFG1 (0.14 µg kg-1) in 10% (3/30); AFG2 (0.6 µg kg-1) in 30% (9/30); AFM1 (1.7 µg kg-1) in 57% (17/30); AFP1 (0.03% µg kg-1) in 3% (1/30); and AFL (13.1 µg kg-1) in 97% (29/30). AFB1 and AFL were the most abundant aflatoxins in Oaxaca-type cheese. However, eight aflatoxins were present, contributing an average of 15.7 µg kg-1 AFs distributed among the 30 samples. The risk assessment analysis showed that there was no substantial risk for cancer due to AFs in industrialized Oaxaca cheese from Mexico City.

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The present study evaluated the exposure of Southeast Mexican population to Aflatoxin M1 (AFM1) and M2 (AFM2) through the consumption of Oaxaca cheese. The intake of Oaxaca cheese was assessed via a food 7-day dairy questionnaire (N = 1100, 2014 and 2015). Thirty Oaxaca cheeses were randomly sampled, and the origin of the samples was also investigated. AFM1 and AFM2 were quantified by HPLC-FD. The exposure was assessed through the combination of the Probabilistic Density Functions (probabilistic approach). The percentage of the population at risk was calculated through the population exceeding the toxicological reference values (TDI). The risk assessment revealed that the population at higher risk to AFM1 and AFM2 was the children, followed by the adolescents and adult women. To our knowledge, the present study is the first to assess the exposure risk of different age groups of a population to AFM1 and AFM2 through the consumption of cheese.

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Mexican fruit fly Anastrepha ludens Loew (Diptera: Tephritidae) is one of the most important insects infesting fruits. Although high pressure has been proposed as an alternative quarantine process for this pest, conditions applied to destroy eggs and larvae can also damage the fruits. The objective of this study was to assess the biological viability of A. ludens eggs treated by high-pressure processing at 0°C, establishing whether nondestroyed eggs and larvae preserved their ability to develop and reproduce. One-, 2-, 3-, and 4-day-old eggs were pressurized at 50, 70, or 90 MPa for 0, 3, 6, or 9 min. The hatching ability of pressurized eggs and their capacity to develop larvae, pupae, and reproductive adults were evaluated. The ability of pressurized larvae to pupate was also registered. The results showed that most of the eggs that resisted the treatments were able to produce adults with capability to reproduce a new generation of A. ludens flies. Larvae were less resistant than eggs. All larvae were killed at 90 MPa for 9 min. The pressure induced the expression of heat shock proteins (HSP) in second- and third-instar larvae. The HSP showed a baroprotective effect in A. ludens larvae. These results are relevant to the industry because they show that eggs of insects infesting fruits treated by high-pressure processing were able to pupate after treatments. This indicates that efforts must be addressed to destroy all eggs because most of the surviving organisms could reach an adult stage and reproduce.

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