A lot of the reviews you will read about this company come from people talking about how the old Kraft or the old Heinz were great and the new company is terrible. This might sound to some like the reviews are coming from bitter former employees who were let go for not being up to par, or maybe people who don't handle change well, etc. That may be true. But don't assume that all the negative reviews come from substandard employees.
The company truly does not have a long term vision for how they will continue to operate at current pace. The 3G model is all about cutting costs and experience - replacing high cost, highly experienced employees with young, inexpensive MBA talent. And there is nothing wrong with that at the surface. The problem occurs when that young, inexperienced talent is brought in to lead projects/department, etc. and they don't have anyone to coach, mentor, or train them. There are serious risks that the company takes and exposes itself to, because the decision makers may only have a couple of years in the workforce and don't know what they don't know.
It is becoming less and less common to find people that have been with the company for more than 2 or 3 years, 5+ years (outside of the manufacturing environment) is extremely rare. This company may be a good place for a young MBA grad to get an iconic company name on their resume, maybe even get promoted quickly, and then get out after two years to go find a "real" job. The problem is that that person will quickly find themself failing in any other management role outside of KHC because they have not learned the fundamental things a manager needs to know to succeed in any normal business.
Finally, no mater who you are, you will not be immune to the constant, unexpected layoffs. of course after the acquisition of Kraft, many Kraft employees were let go. Not a huge surprise, but the number of people laid off, and they type of roles eliminated were somewhat concerning. Then, the field restructuring was announced, and hundreds more manufacturing employees will be let go over time as plants consolidate and close. Then, a few months ago, another round of corporate restructuring meant about 200-300 more salaried employees were let go. And this time, it wasn't just the "low hanging fruit" - underperformers or redundant roles. It was the result of senior management saying, "We need to save $XXXXXX in salaries, so each team needs to cut X number of people. Figure it out." So strong performers were let go. Many of the remaining experienced people were let go. people who were critical to major projects were let go. So now what? Already lean teams need to scramble to fill holes, expensive consultants need to be brought in to pick up the work, and the bare minimum level of work will get done. There won't be opportunities to really produce good, quality work. If you are still there, you won't ever feel proud of your work, because your team is so lean, you all have to work yourselves day and night just to produce the bare minimum, because there are no resources available to you. And you will do that day after day because every day you are afraid of losing your job.