Nutritional Assessment of Plant-Based Meat Alternatives: A Comparison of Nutritional Information of Plant-Based Meat Alternatives in Spanish Supermarkets.

Since the classification of processed meat as carcinogenic by the International Agency for Research on Cancer (IARC) in 2015, an increase in consumption of plant-based meat alternatives (PBMAs) has been observed worldwide. This occurs in a context characterized by concern for health, animal welfare, and sustainability; however, evidence of their nutritional quality is still limited. Therefore, our objective was to evaluate the nutritional profile and processing degree of PBMAs available in Spain. In 2020, products from seven Spanish supermarkets were analyzed for their nutritional content and ingredients. Of the 148 products, the majority were low in sugars but moderate in carbohydrates, total and saturated fat, and high in salt. The main vegetable protein sources were soy (91/148) and wheat gluten (42/148). Comparatively, 43/148 contained animal protein, the most common being egg. Overall, PBMAs had a long list of ingredients and additives, and they were classified as ultra-processed foods (UPFs) according to the NOVA system. This study shows that the PBMAs available in Spanish supermarkets have a variable nutritional composition within and between categories. Further research is needed to determine if replacing meat with these UPFs could be a good alternative towards healthier and more sustainable dietary patterns.

Culture-independent bacterial cell extraction from fluid milk and oat-based beverage for basic qualitative microscopy.

Butterfat and protein complicate attempts to extract bacterial cells from milk by centrifugation for use in basic microscopy. Some types of bacteria preferentially separate into the butterfat layer upon centrifugation and are lost when this layer is discarded, and the action of bacterial protease enzymes can cause milk proteins to precipitate and partition into the centrifugal pellet. Butterfat and precipitated protein remaining in the centrifugal pellet along with the desired bacterial cells can confound the results of differential staining and microscopy. Oat- and other plant-based beverages, which are often manufactured by dairy processors on shared equipment, present similar hurdles to bacterial extraction and microscopic visualization because of the presence of oils, starch granules, and dietary fiber particles in these products. Herein we describe methods for centrifugal separation of bacterial cells for microscopy from unflavored milk, chocolate milk, and oat-based beverage. Cell suspensions prepared through these methods were used for phase-contrast microscopy, Gram staining, and viability staining. These techniques can be used to provide rapid, culture-independent diagnostic information when bacterial cells are expected to be present in high concentrations, as in the event of sporadic product spoilage or mass product spoilage incidents.

Enhanced thermal resistance of Salmonella in marinated whole muscle compared with ground pork.

The internal muscle environment may enhance thermal resistance of bacterial pathogens. Based on the migration of pathogens into whole muscle products during marination, the validity of current thermal inactivation models for whole muscle versus ground products has been questioned. Consequently, the objective of this work was to compare thermal resistance of Salmonella in whole muscle versus ground pork. Irradiated samples of whole and ground pork loin (5.5 to 7.5 g) were exposed to a Salmonella-inoculated (10(8) CFU/ml) marinade (eight serovar cocktail) for 20 min, placed in sterile brass tubes (12.7 mm diameter), sealed, and heated isothermally at 55, 58, 60, 62, or 63 degrees C, and surviving salmonellae were enumerated on Petrifilm aerobic count plates. The thermal lag times and initial bacterial counts were similar for both whole muscle and ground samples (P > 0.05), with all samples having equivalent compositions, inocula, and thermal histories. Heating temperature and physical state of the meat (whole versus ground muscle) affected Salmonella inactivation, with greater thermal resistance observed in whole than in ground muscle (P < 0.05). Assuming log-linear inactivation kinetics, Salmonella was 0.64 to 2.96 times more heat resistant in whole muscle than in ground pork. Therefore, thermal process validations for pork products should also account for the physical state of the product to ensure microbial safety.

Effect of beef product physical structure on Salmonella thermal inactivation.

Numerous studies have assessed thermal inactivation of Salmonella in beef. However, the impact of muscle structure has been considered only recently, with several studies reporting enhanced thermal resistance in whole-muscle as compared to ground meat. The functional relationship between meat product physical structure and Salmonella thermal resistance has not been reported; therefore, it is not known whether thermal resistance is affected by the degree of grinding (that is, size of resulting particles). The objective of this study was to evaluate the relationship between thermal resistance of Salmonella and degree of grinding (whole-muscle, coarsely ground, finely ground, and beef puree). Each of the 4 product types was irradiated to sterility and inoculated with a marinade containing an 8-serovar Salmonella cocktail to achieve approximately 10(7.8) CFU/g. Samples (5 g each) were packed into sterile brass tubes, which were sealed, held at 60 degrees C in a water bath, and removed at 30 s intervals. Samples were then serially diluted and plated on Petrifilm aerobic count plates to enumerate surviving salmonellae. All samples had the same composition, thermal history, and initial Salmonella counts; therefore, differences in thermal resistance were due entirely to the degree of grinding. Overall, thermal resistance of Salmonella was highest (P < 0.0001) in whole-muscle (D = 2.7 min), but there were no differences among the 3 ground products (D(mean)= 1.2 min). Therefore, it would be prudent for Salmonella thermal inactivation models to consider whether a product is whole-muscle or ground, but not necessarily the degree of grinding. Practical Application: The results of this study suggest that thermal process validations for ready-to-eat meat products should also consider the structure of the product (which in this study was changed by the physical act of grinding). Salmonella was more resistant to heat in whole-muscle beef than in ground products; however, the degree of grinding did not affect the resistance.

Thermal inactivation kinetics for Salmonella enteritidis PT30 on almonds subjected to moist-air convection heating.

A traditional thermal inactivation kinetic model (D- and z-value) was modified to account for the effect of process humidity on thermal inactivation of Salmonella Enteritidis PT30 on the surface of almonds subjected to moist-air heating. Raw almonds were surface inoculated to approximately 10(8) CFU/g and subjected to moist-air heating in a computer-controlled laboratory-scale convection oven. Time-temperature data were collected for 125 conditions (five dry bulb temperatures, 121 to 232 degrees C; five process humidity levels, 5 to 90% moisture by volume; and five process durations). Moisture status at the surface of the almond, rather than the humidity of the bulk air, was a primary factor controlling the rate of inactivation; therefore, the D-value could not be a simple function of process temperature. Instead, the traditional D- and z-value model was modified to account for the dynamic water status at the surface of the product under humid heating conditions. The modified model needs only the dew point temperature of the processing air and dynamic surface temperature history of the almonds during moist-air heating. The modified model was more robust and accurate than the traditional model. The accuracy of the modified model was improved by 32 to 44% (in terms of the root mean squared error [RMSE] for the model fit) when compared with the traditional model in all moist-air heating conditions. Also, the prediction error of the modified model (RMSE = 1.33 log reductions) against an independent validation data set was approximately one-half that of the traditional model (RMSE = 2.56 log reduction) in the humidity range of 5 to 90% moisture by volume.

Thermal Inactivation of Escherichia coli O157: H7, Salmonella senftenberg , and Enzymes with Potential as Time-Temperature Indicators in Ground Beef.

The USDA has established processing schedules for beef products based on the destruction of pathogens. Several enzymes have been suggested as potential indicators of heat processing. However, no relationship between the inactivation rates of these enzymes and those of pathogenic microorganisms has been determined. Our objective was to compare the thermal inactivation of Escherichia coli O157:H7 and Salmonella senftenberg to those of endogenous muscle proteins. Inoculated and noninoculated ground beef samples were heated at four temperatures for predetermined intervals of time in thermal-death-time studies. Bacterial counts were determined and enzymes were assayed for residual activity. The D values for E. coli O157:H7 were 46.10, 6.44, 0.43, and 0.12 min at 53, 58, 63, and 68°C, respectively, with a z value of 5.60°C. The D values for S. senftenberg were 53.00, 15.17, 2.08, and 0.22 min at 53, 58, 63, and 68°C, respectively, with a z value of 6.24°C. Apparent D values at 53, 58, 63, and 68°C were 352.93, 26.31, 5.56, and 3.33 min for acid phosphatase; 6968.64, 543.48, 19.61, and 1.40 min for lactate dehydrogenase; and 3870.97, 2678.59, 769.23, and 42.92 min for peroxidase; with z values of 7.41,3.99, and 7.80°C, respectively. Apparent D values at 53, 58, 63, and 66°C were 325.03, 60.07, 3.07, and 1.34 min for phosphoglycerate mutase; 606.72, 89.86, 4.40, and 1.28 min for glyceraldehyde-3-phosphate dehydrogenase; and 153.06, 20.13, 2.25, and 0.74 min for triose phosphate isomerase; with z values of 5.18, 4.71, and 5.56°C, respectively. The temperature dependence of triose phosphate isomerase was similar to those of both E. coli O157 :H7 and S. senftenberg , suggesting that this enzyme could be used as an endogenous time-temperature indicator in beef products.